JP6299757B2 - Manufacturing method of solar cell - Google Patents

Manufacturing method of solar cell Download PDF

Info

Publication number
JP6299757B2
JP6299757B2 JP2015518131A JP2015518131A JP6299757B2 JP 6299757 B2 JP6299757 B2 JP 6299757B2 JP 2015518131 A JP2015518131 A JP 2015518131A JP 2015518131 A JP2015518131 A JP 2015518131A JP 6299757 B2 JP6299757 B2 JP 6299757B2
Authority
JP
Japan
Prior art keywords
diffusion layer
type
substrate
outer peripheral
semiconductor substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2015518131A
Other languages
Japanese (ja)
Other versions
JPWO2014188773A1 (en
Inventor
信太郎 月形
信太郎 月形
渡部　武紀
武紀 渡部
大塚　寛之
寛之 大塚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shin Etsu Chemical Co Ltd
Original Assignee
Shin Etsu Chemical Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shin Etsu Chemical Co Ltd filed Critical Shin Etsu Chemical Co Ltd
Publication of JPWO2014188773A1 publication Critical patent/JPWO2014188773A1/en
Application granted granted Critical
Publication of JP6299757B2 publication Critical patent/JP6299757B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
    • H01L31/068—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • H01L31/0684—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells double emitter cells, e.g. bifacial solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • Sustainable Development (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Photovoltaic Devices (AREA)

Description

本発明は、逆バイアス時のリーク電流を抑制する両面受光型の高効率の太陽電池の製造方法に関する。 The present invention relates to the production how high efficiency solar cells suppress bifacial the leakage current when reverse biased.

現在、民生用の太陽電池を製造するにあたって、高効率化及び製造コストの低減が重要課題となっており、太陽電池の研究が広く行われている。その中で変換効率を高めるため、両面にそれぞれリン・ボロンの拡散層を形成する太陽電池がある。その詳細は例えば次の通りである。   At present, in manufacturing consumer-use solar cells, high efficiency and reduction in manufacturing costs are important issues, and research on solar cells is widely conducted. Among them, there is a solar cell in which phosphorus and boron diffusion layers are formed on both sides in order to increase the conversion efficiency. The details are as follows, for example.

まず、チョクラルスキー（ＣＺ）法により作製した単結晶シリコンインゴットやキャスト法により作製した多結晶シリコンインゴットをマルチワイヤー法でスライスすることにより得られたｎ型シリコン基板を用意する。次に、アルカリ溶液で基板表面のスライスによるダメージを取り除いた後、最大高さ１０μｍ程度の微細凹凸（テクスチャ）を表面と裏面との両面に形成する。続いて、基板の両面に異なる導電型のドーパントを熱拡散させる。例えば、表面となる第一主面に基板とは逆導電型となるドーパントガスを用いて気相拡散させて拡散層（エミッタ層）を形成する。他方、裏面となる第二主面には基板と同導電型であるドーパントガスを用いた気相拡散法で拡散させ、拡散層（ＢＳＦ層）を形成する。次に、表面及び裏面にはＴｉＯ2又はＳｉＮｘを、例えば、７０ｎｍ程度の膜厚で堆積させて、反射防止膜を形成する。次に銀を主成分とする裏面電極用ペーストを裏面と表面に櫛型状に印刷し、乾燥させ、焼成することにより電極とオーミックコンタクトを形成し太陽電池が完成する。First, an n-type silicon substrate obtained by slicing a single crystal silicon ingot produced by a Czochralski (CZ) method or a polycrystalline silicon ingot produced by a cast method by a multi-wire method is prepared. Next, after removing damage caused by slicing of the substrate surface with an alkaline solution, fine irregularities (texture) having a maximum height of about 10 μm are formed on both the front surface and the back surface. Subsequently, different conductivity type dopants are thermally diffused on both surfaces of the substrate. For example, a diffusion layer (emitter layer) is formed on the first main surface as a surface by vapor phase diffusion using a dopant gas having a conductivity type opposite to that of the substrate. On the other hand, a diffusion layer (BSF layer) is formed on the second main surface serving as the back surface by diffusing by a vapor phase diffusion method using a dopant gas having the same conductivity type as the substrate. Next, TiO 2 or SiNx is deposited on the front and back surfaces to a thickness of, for example, about 70 nm to form an antireflection film. Next, a back electrode paste containing silver as a main component is printed in a comb shape on the back surface and the surface, dried and fired to form an ohmic contact with the electrode, thereby completing the solar cell.

このようにして作られた太陽電池は、ｐ型半導体基板を用いた一般的な裏面のアルミニウム電極（以下、アルミ電極）を有する太陽電池に比べて、基板裏面側のアルミ電極領域の表面再結合を抑制することができ、高い光電変換特性を有する。また、前記の両面から拡散させた太陽電池は、ｐ型半導体基板を用いた一般的な裏面アルミ電極を有する太陽電池に比べて、基板の反りが小さく、モジュール化の際の割れが少ない。   The solar cell thus fabricated has a surface recombination of the aluminum electrode region on the back side of the substrate, compared to a solar cell having a general back side aluminum electrode (hereinafter referred to as an aluminum electrode) using a p-type semiconductor substrate. And has high photoelectric conversion characteristics. Moreover, the solar cell diffused from both sides has less warpage of the substrate and fewer cracks when modularized, compared to a solar cell having a general back surface aluminum electrode using a p-type semiconductor substrate.

一般的に、太陽電池は正極側の電極と負極側の電極が同じ導電型の拡散層によって接続された場合、シャント抵抗が低下し、発電時にキャリアのリークが増大して太陽電池の変換効率が減少する。   In general, when a positive electrode and a negative electrode are connected by a diffusion layer of the same conductivity type in a solar cell, the shunt resistance decreases, the leakage of carriers increases during power generation, and the conversion efficiency of the solar cell increases. Decrease.

例えば、ｐ型半導体基板を用いた一般的な裏面アルミ電極を有する太陽電池では、ｐｎ接合を形成するために、リン拡散を受光面（表面）又は基板全面に行う。このとき、基板側端部や裏面側に亘って形成されたリン拡散層を介して、受光面電極と裏面電極とが接続されると、シャント抵抗が低下し、発電する際にキャリアのリークが生じて太陽電池特性が低下する。   For example, in a solar cell having a general back surface aluminum electrode using a p-type semiconductor substrate, phosphorus diffusion is performed on the light receiving surface (front surface) or the entire surface of the substrate in order to form a pn junction. At this time, if the light-receiving surface electrode and the back surface electrode are connected via the phosphorous diffusion layer formed over the substrate side end and the back surface side, the shunt resistance decreases, and carrier leakage occurs during power generation. As a result, the solar cell characteristics deteriorate.

このシャント抵抗の低下を防止するために、通常ｐｎ接合を分離する工程が含まれる。その方法としては、受光面外周エッジ部（外周縁）、基板側端部、裏面外周縁領域を除去する方法がある。例えば、ＣＦ4などのエッチングガスを用いて基板側端部をエッチングするプラズマエッチング技術や、機械研磨による基板エッジ除去技術（特開昭５５−００３６３３号公報（特許文献１））、サンドブラストを用いた裏面外周のエッチング（特開２００３−２９８０８０号公報（特許文献２））、更にアルカリ系の溶剤を用いて基板の裏面外周縁を溶融させて拡散層を除去するエッチバック技術やレーザー照射によって接合分離溝を基板裏面外周縁領域に形成する技術（国際公開第２００６／０８７７８６号（特許文献３））がある。これらは、いずれにおいても連続したエミッタ層を不連続とすることが可能であり、シャント抵抗の低下を防止して、ｐｎ接合分離を達成することが可能である。In order to prevent this decrease in shunt resistance, a step of normally separating the pn junction is included. As a method thereof, there is a method of removing the outer peripheral edge portion (outer peripheral edge) of the light receiving surface, the substrate side end portion, and the rear outer peripheral edge region. For example, plasma etching technology that etches the substrate side edge using an etching gas such as CF 4 , substrate edge removal technology by mechanical polishing (Japanese Patent Laid-Open No. 55-003633 (Patent Document 1)), and sandblasting are used. Etching of the outer periphery of the back surface (Japanese Patent Application Laid-Open No. 2003-298080 (Patent Document 2)), joining and separating by laser irradiation or etch back technology that melts the outer periphery of the back surface of the substrate using an alkaline solvent to remove the diffusion layer There is a technique (International Publication No. 2006/087786 (Patent Document 3)) for forming a groove in the outer peripheral edge region of the back surface of the substrate. In any of these, it is possible to make a continuous emitter layer discontinuous, and it is possible to prevent a decrease in shunt resistance and achieve pn junction isolation.

また、太陽電池特性の一つに逆バイアス時のリーク電流がある。これは、太陽電池を直列接続したモジュールにおいて、太陽電池の一部が影になった場合に、直列接続した他の太陽電池から逆バイアスがかかる。その際、リーク電流の多い、即ち耐圧が低い太陽電池はリーク電流によって局所的に過熱し、太陽電池やモジュールが破損する場合がある。一般的に、逆バイアスのリーク電流は、異なる導電型の拡散層が接する場合、それぞれのドーパント濃度の積に比例し、印加される逆バイアス電圧に比例して増大し、太陽電池の信頼性において重要なパラメーターである。   In addition, one of the solar cell characteristics is leakage current at the time of reverse bias. This is because, in a module in which solar cells are connected in series, a reverse bias is applied from another solar cell connected in series when a part of the solar cell is shaded. At that time, a solar cell with a large leakage current, that is, a low withstand voltage, may locally overheat due to the leakage current, and the solar cell or the module may be damaged. In general, the reverse bias leakage current is proportional to the product of the respective dopant concentrations and increases in proportion to the applied reverse bias voltage when diffusion layers of different conductivity types are in contact with each other. It is an important parameter.

ｐ型半導体基板を用いた一般的な裏面アルミ電極を有する太陽電池では、上記接合分離工程を行うことによって、逆バイアスが印加された場合のリーク電流が小さくなる。これは、アルミ電極を焼成した時に形成されるＢＳＦ層（ｐ+層）がアルミ電極直下のみに局所的に形成され、リン拡散層（ｎ+層）が基板裏面側に回りこんで形成された場合でも、ｎ+層とｐ+層が接する領域が裏面アルミ電極近傍に限定されるからである。従って、受光面エッジ部から裏面外周縁領域のリン拡散層を連続的に除去することが可能な上記接合分離方法によって、ｎ+層が不連続になることによってｎ+ｐ+領域への逆バイアス印加を防ぐことが可能となる。In a solar cell having a general backside aluminum electrode using a p-type semiconductor substrate, the leakage current when a reverse bias is applied is reduced by performing the junction separation step. This is because the BSF layer (p + layer) formed when the aluminum electrode is baked is locally formed only directly under the aluminum electrode, and the phosphorus diffusion layer (n + layer) is formed around the back side of the substrate. Even in this case, the region where the n + layer and the p + layer are in contact is limited to the vicinity of the back surface aluminum electrode. Therefore, by the above-described junction separation method capable of continuously removing the phosphorous diffusion layer in the outer peripheral edge region from the light receiving surface edge portion, the reverse bias to the n + p + region due to the discontinuity of the n + layer. Application can be prevented.

一方、上記基板両面から拡散させた太陽電池は、ｐ型及びｎ型の異なる拡散層を形成することが必要であり、ボロンドーパントよりも拡散しやすいリンドーパントがリン拡散面だけでなく、基板側端部やボロン拡散面の外周縁領域に拡散し、高濃度リン拡散層が形成されてしまう。   On the other hand, the solar cell diffused from both sides of the substrate requires the formation of different p-type and n-type diffusion layers, and the phosphorus dopant that diffuses more easily than the boron dopant is not only the phosphorus diffusion surface, but also on the substrate side. It diffuses to the outer peripheral edge region of the end portion or boron diffusion surface, and a high concentration phosphorus diffusion layer is formed.

また、一般的に逆バイアス時のリーク電流はエミッタ層に接するＢＳＦ層のドーパント濃度に比例して増大する。   In general, the leakage current during reverse bias increases in proportion to the dopant concentration of the BSF layer in contact with the emitter layer.

そのため、ｐ型半導体基板を用いた一般的な裏面アルミ電極を有する太陽電池では効果のあった上記接合分離方法では、基板両面から拡散させた太陽電池を完全にｐｎ接合分離することができず、逆バイアス時のリーク電流が少ない高効率の太陽電池を歩留まり良く作製することが困難であった。   Therefore, in the solar cell having a general back surface aluminum electrode using a p-type semiconductor substrate, the above-described junction separation method, which is effective, cannot completely separate the solar cell diffused from both sides of the substrate. It has been difficult to produce a high-efficiency solar cell with low leakage current during reverse bias with good yield.

また、基板両面に拡散層を形成した太陽電池は、逆バイアス印加時のリーク電流が多くなり、リーク電流発生部において基板温度が上昇することでセル及びモジュールを損傷する可能性が高くなるため、モジュール信頼性を低下させる要因となっていた。   In addition, the solar cell in which the diffusion layers are formed on both surfaces of the substrate increases the leakage current at the time of reverse bias application, and increases the possibility of damaging the cell and the module by increasing the substrate temperature in the leakage current generation part. This was a factor that reduced module reliability.

特開昭５５−００３６３３号公報JP-A-55-003633 特開２００３−２９８０８０号公報JP 2003-298080 A 国際公開第２００６／０８７７８６号International Publication No. 2006/087786

本発明は、上記事情に鑑みなされたもので、基板両面から拡散させた太陽電池の表面と裏面とを電気的に分離し、逆バイアス時のリーク電流の少ない高効率の両面受光型の太陽電池の製造方法を提供することを目的とする。 The present invention has been made in view of the above circumstances, and is a high-efficiency double-sided light-receiving solar cell that electrically separates the front and back surfaces of a solar cell diffused from both sides of the substrate and has little leakage current during reverse biasing. an object of the present invention is to provide a manufacturing how.

本発明者らは、鋭意研究の結果、基板両面から拡散させた太陽電池の接合分離方法として、表面外周縁領域のエミッタ層内に接合分離溝を形成することが高セル特性及び逆バイアス時の低リーク電流に対して最も効果的であるという結論に至り、更に鋭意検討して本発明を成すに至った。   As a result of diligent research, the present inventors have found that, as a method for separating the solar cell diffused from both sides of the substrate, it is possible to form a junction separation groove in the emitter layer in the outer peripheral region of the surface. It came to the conclusion that it is the most effective for low leakage current, and further intensive investigations led to the present invention.

即ち、本発明は、下記の太陽電池の製造方法を提供する。
〔１〕 ｎ型半導体基板の裏面を露出させ表面をシリコン酸化膜でマスクした状態で該裏面にｎ型ドーパントを含む拡散剤を塗布した後に熱処理してｎ型拡散層を形成する処理と、上記ｎ型半導体基板の表面を露出させそれ以外はシリコン酸化膜でマスクした状態で該表面にｐ型ドーパントを含む拡散剤を塗布した後に熱処理してｐ型拡散層を形成する処理とをこの順番で行って、又はｎ型半導体基板の表面にｐ型ドーパントを含む拡散剤を塗布し、この状態の２枚の基板の拡散剤を塗布した表面同士を向き合わせて重ね合わせた状態で拡散熱処理を行うと共にこの時にｎ型ドーパントを含むガスを導入して基板の裏面にｎ型拡散層を形成する処理と表面にｐ型拡散層を形成する処理とを同時に行って、基板の裏面、基板側端部及び表面の外周縁領域にｎ型拡散層が連続して形成され、表面の外周縁領域のｎ型拡散層よりも内側で該ｎ型拡散層に接するｐ型拡散層が形成されたｎ型半導体基板を得る工程と、上記ｎ型半導体基板の表面のｐ型拡散層の外周縁部に沿ってレーザー照射して該ｐ型拡散層の外周縁部より内側の部分の拡散層を除去し、基板表面のｐ型拡散層の領域においてｎ型半導体基板が露出した状態であって、ｎ型半導体基板の表面と裏面とを電気的に分離する接合分離部を形成する工程とを有することを特徴とする両面受光型の太陽電池の製造方法。
〔２〕 ｐ型半導体基板の表面を露出させ裏面をシリコン酸化膜でマスクした状態で該表面にｎ型ドーパントを含む拡散剤を塗布した後に熱処理してｎ型拡散層を形成する処理と、上記ｐ型半導体基板の裏面を露出させそれ以外はシリコン酸化膜でマスクした状態で該裏面にｐ型ドーパントを含む拡散剤を塗布した後に熱処理してｐ型拡散層を形成する処理とをこの順番で行って、又はｐ型半導体基板の裏面にｐ型ドーパントを含む拡散剤を塗布し、この状態の２枚の基板の拡散剤を塗布した裏面同士を向き合わせて重ね合わせた状態で拡散熱処理を行うと共にこの時にｎ型ドーパントを含むガスを導入して基板の表面にｎ型拡散層を形成する処理と裏面にｐ型拡散層を形成する処理とを同時に行って、基板の表面、基板側端部及び裏面の外周縁領域にｎ型拡散層が連続して形成され、裏面の外周縁領域のｎ型拡散層よりも内側で該ｎ型拡散層に接するｐ型拡散層が形成されたｐ型半導体基板を得る工程と、上記ｐ型半導体基板の表面のｎ型拡散層の外周縁部に沿ってレーザー照射して該ｎ型拡散層の外周縁部より内側の部分の拡散層を除去し、基板表面のｎ型拡散層の領域においてｐ型半導体基板が露出した状態であって、ｐ型半導体基板の表面と裏面とを電気的に分離する接合分離部を形成する工程とを有することを特徴とする両面受光型の太陽電池の製造方法。
〔３〕 接合分離部は、幅の中心が表面外周縁から０．１５ｍｍ以上０．６０ｍｍ以下の距離だけ内側に入った領域内で基板外周縁に沿って表面電極よりも外側に連続的に形成された溝であることを特徴とする〔１〕又は〔２〕記載の太陽電池の製造方法。
〔４〕 接合分離部は、溝幅が５μｍ以上３０μｍ以下であり、溝深さが５μｍ以上３０μｍ以下の溝であることを特徴とする〔１〕〜〔３〕のいずれかに記載の太陽電池の製造方法。
That is, the present invention provides a manufacturing how a solar cell below.
[1] A process of forming an n-type diffusion layer by applying a diffusing agent containing an n-type dopant to the back surface while exposing the back surface of the n-type semiconductor substrate and masking the surface with a silicon oxide film, In this order, the surface of the n-type semiconductor substrate is exposed and the surface is otherwise masked with a silicon oxide film, and a diffusion agent containing a p-type dopant is applied to the surface, followed by heat treatment to form a p-type diffusion layer. Or by applying a diffusion agent containing a p-type dopant to the surface of the n-type semiconductor substrate, and performing diffusion heat treatment in a state in which the surfaces of the two substrates applied in this state face each other and overlap each other. At the same time, the process of forming a n-type diffusion layer on the back surface of the substrate by introducing a gas containing an n-type dopant and the process of forming a p-type diffusion layer on the front surface are performed simultaneously. And the outer circumference of the surface A step of obtaining an n-type semiconductor substrate in which an n-type diffusion layer is continuously formed in an edge region, and a p-type diffusion layer in contact with the n-type diffusion layer is formed on the inner side of the n-type diffusion layer in the outer peripheral region of the surface And laser irradiation along the outer peripheral edge of the p-type diffusion layer on the surface of the n-type semiconductor substrate to remove the diffusion layer inside the outer peripheral edge of the p-type diffusion layer, and A double-sided light receiving type comprising: a step of forming a junction separation portion for electrically separating the front surface and the back surface of the n-type semiconductor substrate, wherein the n-type semiconductor substrate is exposed in the region of the diffusion layer; Solar cell manufacturing method.
[2] A process of forming an n-type diffusion layer by applying a diffusing agent containing an n-type dopant to the surface in a state where the surface of the p-type semiconductor substrate is exposed and the back surface is masked with a silicon oxide film, A process of forming a p-type diffusion layer in this order by applying a diffusing agent containing a p-type dopant to the back surface in a state where the back surface of the p-type semiconductor substrate is exposed and otherwise masked with a silicon oxide film. Or a diffusion heat treatment is performed in a state in which the back surface of the p-type semiconductor substrate is coated with a diffusing agent containing a p-type dopant and the back surfaces of the two substrates coated with the diffusing agent face each other and overlap each other. At the same time, a process for forming an n-type diffusion layer on the surface of the substrate by introducing a gas containing an n-type dopant and a process for forming a p-type diffusion layer on the back surface are performed simultaneously. And the outer periphery of the back A step of obtaining a p-type semiconductor substrate in which an n-type diffusion layer is continuously formed in an edge region and a p-type diffusion layer in contact with the n-type diffusion layer is formed on the inner side of the n-type diffusion layer in the outer peripheral region on the back surface. And laser irradiation along the outer peripheral edge of the n-type diffusion layer on the surface of the p-type semiconductor substrate to remove the diffusion layer inside the outer peripheral edge of the n-type diffusion layer, A double-sided light receiving type comprising: a step of forming a junction separation portion for electrically separating a front surface and a back surface of the p-type semiconductor substrate in a state where the p-type semiconductor substrate is exposed in the region of the diffusion layer Solar cell manufacturing method.
[ 3 ] The junction separation portion is continuously formed outside the surface electrode along the outer peripheral edge of the substrate in a region where the center of the width enters the inner side by a distance of 0.15 mm to 0.60 mm from the outer peripheral edge of the surface. The method for producing a solar cell according to [1] or [2], wherein the method is a groove formed.
[ 4 ] The solar cell according to any one of [1] to [ 3 ], wherein the junction separation portion is a groove having a groove width of 5 μm to 30 μm and a groove depth of 5 μm to 30 μm. Manufacturing method.

本発明によれば、半導体基板の表面の外周縁領域でレーザー接合分離を行うことで、逆バイアス時のリーク電流の少ない高効率の太陽電池を歩留まり良く作製することができる。   According to the present invention, by performing laser junction separation in the outer peripheral region of the surface of a semiconductor substrate, a highly efficient solar cell with little leakage current at the time of reverse bias can be manufactured with high yield.

本発明に係る太陽電池の基本構成を示す正面図であり、（ａ）は表面の正面図、（ｂ）は裏面の正面図である。It is a front view which shows the basic composition of the solar cell which concerns on this invention, (a) is a front view of the surface, (b) is a front view of a back surface. 本発明に係る太陽電池の基本構成を示す断面図である。It is sectional drawing which shows the basic composition of the solar cell which concerns on this invention. 本発明に係る太陽電池の製造方法の実施形態としての製造工程を示す断面図であり、（ａ）はテクスチャ形成工程、（ｂ）は拡散層形成工程、（ｃ）は反射防止膜兼パッシベーション膜形成工程、（ｄ）はレーザー接合分離工程、（ｅ）は電極形成工程である。It is sectional drawing which shows the manufacturing process as embodiment of the manufacturing method of the solar cell concerning this invention, (a) is a texture formation process, (b) is a diffused layer formation process, (c) is an antireflection film and passivation film. A forming process, (d) is a laser bonding separation process, and (e) is an electrode forming process. 本発明に係る太陽電池においてｎ型半導体基板を用いた第１の実施形態を示す断面図である。It is sectional drawing which shows 1st Embodiment using the n-type semiconductor substrate in the solar cell which concerns on this invention. 図４の太陽電池における接合分離溝の形成例を示す正面図である。It is a front view which shows the example of formation of the junction isolation groove in the solar cell of FIG. 図４の太陽電池における接合分離溝の別の形成例を示す正面図である。It is a front view which shows another example of formation of the junction isolation groove in the solar cell of FIG. 本発明に係る太陽電池においてｐ型半導体基板を用いた第２の実施形態を示す断面図である。It is sectional drawing which shows 2nd Embodiment using the p-type semiconductor substrate in the solar cell which concerns on this invention. 図７の太陽電池における接合分離溝の形成例を示す正面図である。It is a front view which shows the example of formation of the junction isolation groove in the solar cell of FIG. 図７の太陽電池における接合分離溝の別の形成例を示す正面図である。It is a front view which shows another example of formation of the junction isolation groove in the solar cell of FIG. 比較例１の太陽電池の概略構成を示す断面図である。4 is a cross-sectional view showing a schematic configuration of a solar cell of Comparative Example 1. FIG. 比較例２の太陽電池の概略構成を示す断面図である。6 is a cross-sectional view showing a schematic configuration of a solar cell of Comparative Example 2. FIG. 比較例３の太陽電池の概略構成を示す断面図である。10 is a cross-sectional view showing a schematic configuration of a solar cell of Comparative Example 3. FIG. 比較例４の太陽電池の概略構成を示す断面図である。10 is a cross-sectional view showing a schematic configuration of a solar cell of Comparative Example 4. FIG.

以下、本発明に係る太陽電池の製造方法及び太陽電池について説明する。
図１及び図２に、本発明に係る太陽電池の基本構成を示す。
本発明の太陽電池は、半導体基板の両面に拡散層が形成された両面受光型の太陽電池であり、図１（ａ）に示すように、半導体基板の表面において集電電極としてフィンガー電極１６ｆと呼ばれる数百〜数十μｍ幅の電極を多数有し、また太陽電池を連結するための集電電極としてのバスバー電極１６ｂを２本有する。また、図１（ｂ）に示すように、半導体基板の裏面においても集電電極としてのフィンガー電極１７ｆと、太陽電池を連結するための集電電極としてのバスバー電極１７ｂを２本有する。Hereinafter, a method for manufacturing a solar cell and a solar cell according to the present invention will be described.
1 and 2 show a basic configuration of a solar cell according to the present invention.
The solar cell of the present invention is a double-sided light-receiving solar cell in which diffusion layers are formed on both sides of a semiconductor substrate. As shown in FIG. 1A, the surface of the semiconductor substrate has finger electrodes 16f as current collecting electrodes. It has a large number of electrodes having a width of several hundreds to several tens of μm, and two bus bar electrodes 16b as current collecting electrodes for connecting solar cells. As shown in FIG. 1B, the back surface of the semiconductor substrate also has two finger electrodes 17f as current collecting electrodes and two bus bar electrodes 17b as current collecting electrodes for connecting solar cells.

また、この太陽電池の断面構造として、図２に示すように、ｎ型の半導体基板１０ｎの表面側には基板の導電型と逆の導電型（ｐ型）の拡散層１２ｐが設けられ、この上にフィンガー電極１６ｆ及びバスバー電極１６ｂが設けられる（バスバー電極１６ｂは不図示）。なお、拡散層１２ｐのそれ以外の領域には反射防止膜兼パッシベーション膜１３が設けられている。また、半導体基板１０ｎの裏面側には基板の導電型と同一の導電型（ｎ型）の拡散層１２ｎが設けられ、この上にフィンガー電極１７ｆ及びバスバー電極１７ｂが設けられ（バスバー電極１７ｂは不図示）、それ以外の領域には反射防止膜兼パッシベーション膜１４が設けられる。   As a cross-sectional structure of this solar cell, as shown in FIG. 2, a diffusion layer 12p having a conductivity type (p-type) opposite to the conductivity type of the substrate is provided on the surface side of the n-type semiconductor substrate 10n. The finger electrode 16f and the bus bar electrode 16b are provided on the top (the bus bar electrode 16b is not shown). An antireflection film / passivation film 13 is provided in the other region of the diffusion layer 12p. Further, a diffusion layer 12n having the same conductivity type (n-type) as that of the substrate is provided on the back surface side of the semiconductor substrate 10n, and a finger electrode 17f and a bus bar electrode 17b are provided thereon (the bus bar electrode 17b is not formed). In the other region, an antireflection film / passivation film 14 is provided.

なお、図２において、ｐ型の半導体基板１０ｐの場合には、基板の表面側には基板の導電型と逆の導電型（ｎ型）の拡散層１２ｎが設けられ、裏面側には基板の導電型と同一の導電型（ｐ型）の拡散層１２ｐが設けられる。それ以外の構成は上記と同じである。   2, in the case of a p-type semiconductor substrate 10p, a diffusion layer 12n having a conductivity type (n-type) opposite to the conductivity type of the substrate is provided on the front surface side of the substrate, and on the back surface side of the substrate. A diffusion layer 12p of the same conductivity type (p-type) as the conductivity type is provided. Other configurations are the same as above.

本発明に係る太陽電池の製造方法は、半導体基板の表面に該半導体基板とは逆の導電型となる拡散層を形成する工程と、上記半導体基板の裏面に該半導体基板と同一の導電型となる拡散層を形成する工程と、上記半導体基板の表面の該半導体基板とは逆の導電型の拡散層（エミッタ層となる領域）の外周縁部に沿ってレーザー照射して該拡散層の外周縁部を除去し、半導体基板の表面と裏面とを電気的に分離する接合分離溝を形成する工程とを有することを特徴とする。   The method for manufacturing a solar cell according to the present invention includes a step of forming a diffusion layer having a conductivity type opposite to the semiconductor substrate on the surface of the semiconductor substrate, and a conductivity type identical to that of the semiconductor substrate on the back surface of the semiconductor substrate. Forming a diffusion layer, and irradiating a laser along the outer peripheral edge of a diffusion layer (a region serving as an emitter layer) of the conductivity type opposite to the semiconductor substrate on the surface of the semiconductor substrate. And a step of forming a junction separation groove for electrically separating the front surface and the back surface of the semiconductor substrate by removing the peripheral portion.

以下、図３に基づき、本発明の太陽電池の製造方法を具体的に説明する。
［シリコン基板の準備］
高純度シリコンにリンあるいは砒素、アンチモンのようなＶ族元素をドープし、比抵抗０．１〜５Ω・ｃｍとしたアズカット単結晶｛１００｝ｎ型シリコン基板表面のスライスダメージを、濃度５〜６０質量％の水酸化ナトリウムや水酸化カリウムのような高濃度のアルカリもしくはふっ酸と硝酸の混酸などを用いてエッチングする。単結晶シリコン基板は、ＣＺ法、ＦＺ法のいずれの方法によって作製されてもよい。基板は必ずしも単結晶シリコンである必要はなく、多結晶シリコンや化合物半導体でも構わない。また、シリコン基板の形状も特に限定されず、矩形、円形のいずれでもよい。ここでは、ｎ型単結晶シリコン基板であるｎ型半導体基板１０ｎ（以下、基板１０ｎ）を用いる場合を説明する。Hereinafter, based on FIG. 3, the manufacturing method of the solar cell of this invention is demonstrated concretely.
[Preparation of silicon substrate]
High purity silicon is doped with a group V element such as phosphorus, arsenic, or antimony, and has a specific resistance of 0.1-5 Ω · cm. Etching is performed using a high concentration alkali such as sodium hydroxide or potassium hydroxide of a mass% or a mixed acid of hydrofluoric acid and nitric acid. The single crystal silicon substrate may be manufactured by either the CZ method or the FZ method. The substrate is not necessarily made of single crystal silicon, but may be polycrystalline silicon or a compound semiconductor. Further, the shape of the silicon substrate is not particularly limited, and may be rectangular or circular. Here, a case where an n-type semiconductor substrate 10n (hereinafter referred to as a substrate 10n) which is an n-type single crystal silicon substrate is used will be described.

［テクスチャ形成工程］
引き続き、基板１０ｎの両面にテクスチャと呼ばれる微小な凹凸形成を行う（図３では凹凸表示省略）。テクスチャは太陽電池の反射率を低下させるための有効な方法である。テクスチャは、基板１０ｎを加熱した水酸化ナトリウム、水酸化カリウム、炭酸カリウム、炭酸ナトリウム、炭酸水素ナトリウムなどのアルカリ溶液（濃度１〜１０質量％、温度６０〜１００℃）中に１０〜３０分間程度浸漬することで形成される。上記溶液中に、所定量の２−プロパノールを溶解させ、反応を促進させることが多い。テクスチャ形成は、表面のエッチングを行っていることになるため、前記ダメージエッチングの代用とすることも可能である。
以上の工程の後、塩酸、硫酸、硝酸、ふっ酸等もしくはこれらの混合液の酸性水溶液中で基板１０ｎを洗浄する（ここまで図３（ａ））。[Texture formation process]
Subsequently, fine unevenness called texture is formed on both surfaces of the substrate 10n (not shown in FIG. 3). Texture is an effective way to reduce solar cell reflectivity. The texture is about 10 to 30 minutes in an alkaline solution (concentration: 1 to 10% by mass, temperature: 60 to 100 ° C.) such as sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium hydrogen carbonate, etc., in which the substrate 10n is heated. It is formed by dipping. In many cases, a predetermined amount of 2-propanol is dissolved in the solution to promote the reaction. Since the texture is formed by etching the surface, it can be used instead of the damage etching.
After the above steps, the substrate 10n is washed in an acidic aqueous solution of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, or the like or a mixture thereof (up to this point, FIG. 3A).

［拡散層形成工程］
次いで、基板１０ｎの両面に拡散層１２ｐ、１２ｎを形成する（図３（ｂ））。
詳しくは、まず基板１０ｎの裏面（第二主面、図３において下向きの面）に基板１０ｎの導電型と同一の導電型（第一の導電型）となる拡散源（Ｐ、Ａｓ、Ｓｂ等のドーパント）を含む拡散剤、例えばリンやアンチモン等を含有する材料を塗布し乾燥させることで拡散剤塗布層を形成し、８００〜１，０００℃で３０分〜１時間程度の熱処理を施すことで、第二主面上にｎ型の拡散層１２ｎを形成する。なお、このとき、基板１０ｎの表面に拡散層の形成を防止するマスクとしてシリコン酸化膜を形成しておくとよい。
次に、基板１０ｎの表面（第一主面、図３において上向きの面）に基板１０ｎの導電型と逆の導電型（第二の導電型）となる拡散源（Ｂ、Ａｌ、Ｇａ、Ｉｎ等のドーパント）を含む拡散剤、例えば予めホウ酸を純水に溶解しておいた拡散剤を塗布し乾燥させることで、拡散剤塗布層を形成し、９５０〜１，０５０℃で１０分〜１時間程度の熱処理を施すことで、第一主面上にｐ型の拡散層１２ｐを形成する。[Diffusion layer forming step]
Next, diffusion layers 12p and 12n are formed on both surfaces of the substrate 10n (FIG. 3B).
Specifically, first, a diffusion source (P, As, Sb, etc.) having the same conductivity type (first conductivity type) as that of the substrate 10n on the back surface (second main surface, the downward surface in FIG. 3) of the substrate 10n. A diffusing agent containing a dopant), for example, a material containing phosphorus, antimony, or the like is applied and dried to form a diffusing agent coating layer and subjected to heat treatment at 800 to 1,000 ° C. for about 30 minutes to 1 hour. Thus, the n-type diffusion layer 12n is formed on the second main surface. At this time, a silicon oxide film may be formed on the surface of the substrate 10n as a mask for preventing the formation of a diffusion layer.
Next, a diffusion source (B, Al, Ga, In) having a conductivity type (second conductivity type) opposite to that of the substrate 10n is formed on the surface (first main surface, the upward surface in FIG. 3) of the substrate 10n. A diffusing agent containing a dopant such as boric acid previously dissolved in pure water and drying to form a diffusing agent coating layer, and 950 to 1,050 ° C. for 10 minutes to By performing heat treatment for about one hour, the p-type diffusion layer 12p is formed on the first main surface.

なお、基板１０ｎの表面（第一主面）に第二の導電型の拡散剤を塗布して拡散剤塗布層を形成した後、拡散熱処理時に雰囲気ガスとして第一の導電型の拡散源を供給するガス、例えばオキシ塩化リンを導入することで、基板１０ｎの第二主面にｎ型の拡散層１２ｎを同時に形成するようにしてもよい（気相拡散法）。この場合、２枚の基板１０ｎの拡散剤塗布層を形成した第一主面同士を向き合わせて重ね合わせた状態で上記拡散熱処理を施すとよい。
拡散熱処理が終わったら、基板１０ｎ表面に形成されたガラスをふっ酸などで除去する。After the second conductive type diffusing agent is applied to the surface (first main surface) of the substrate 10n to form the diffusing agent coating layer, the first conductive type diffusion source is supplied as an atmospheric gas during the diffusion heat treatment. An n-type diffusion layer 12n may be simultaneously formed on the second main surface of the substrate 10n by introducing a gas such as phosphorus oxychloride (vapor phase diffusion method). In this case, the diffusion heat treatment may be performed in a state where the first principal surfaces on which the diffusing agent coating layers of the two substrates 10n are formed face each other and overlap each other.
After the diffusion heat treatment, the glass formed on the surface of the substrate 10n is removed with hydrofluoric acid or the like.

［反射防止膜兼パッシベーション膜形成工程］
次いで、基板１０ｎの表裏面に反射防止膜兼パッシベーション膜１３、１４を形成する（図３（ｃ））。反射防止膜兼パッシベーション膜１３、１４の形成にはプラズマＣＶＤ装置を用いＳｉＮｘ膜を厚さ約１００ｎｍで製膜する。なお、反応ガスとして、モノシラン（ＳｉＨ4）及びアンモニア（ＮＨ3）を混合して用いることが多いが、ＮＨ3の代わりに窒素を用いることも可能であり、また、プロセス圧カの調整、反応ガスの希釈、更には基板に多結晶シリコンを用いた場合には基板のバルクパッシベーション効果を促進するため、反応ガスに水素を混合することもある。[Antireflection film / passivation film forming process]
Next, antireflection films and passivation films 13 and 14 are formed on the front and back surfaces of the substrate 10n (FIG. 3C). The antireflection film and passivation films 13 and 14 are formed by using a plasma CVD apparatus to form a SiNx film with a thickness of about 100 nm. As the reaction gas, monosilane (SiH 4 ) and ammonia (NH 3 ) are often mixed and used, but nitrogen can be used instead of NH 3 , and the process pressure can be adjusted and reacted. In the case of diluting the gas, and further using polycrystalline silicon for the substrate, hydrogen may be mixed into the reaction gas in order to promote the bulk passivation effect of the substrate.

ところで、基板１０ｎの両面それぞれに形成される拡散層１２ｐ、１２ｎは、拡散熱処理において、所望の面だけに形成されるものではない。例えば、表面側にボロン拡散を行っている際には、裏面側にもボロンオートドープによりボロン拡散層が形成される。また、裏面側にリン拡散を行っている際にも表面側にリンオートドープが起こり、リン拡散層が形成される。その結果、基板側端部及び表面外周縁領域において、ボロンドーパントよりも拡散係数が大きいリンドーパントによってリンドーパントの拡散濃度が高くなってしまい、図３（ｂ）に示すようにこれらの領域のボロン濃度が補償され、基板側端部及び表面（ボロン拡散面）外周縁領域に高濃度リン拡散層（ｎ+層）１２ｎが連続して形成されることになる。これは基板の表面（ボロン拡散面）にマスク用のシリコン酸化膜を形成しておいても発生する。なお、表面（ボロン拡散面）外周縁領域における高濃度リン拡散層１２ｎの幅は、ｐ型基板を用いた抵抗測定により、外周縁から少なくとも０．０８ｍｍまで、最大０．１２ｍｍまでの領域に亘って形成されていることを確認した。また、表面（ボロン拡散面）外周縁領域における高濃度リン拡散層１２ｎの幅は、上記マスク用のシリコン酸化膜を形成した後に拡散熱処理を施した場合と、２枚の基板１０ｎの拡散剤塗布層を形成した第一主面同士を向き合わせて重ね合わせた状態で上記拡散熱処理を施した場合とで同程度であった。
この高濃度リン拡散層（ｎ+層）１２ｎが高濃度ボロン拡散層（ｐ+層）１２ｐに接している状態（ｐ+ｎ+接合）で、この領域に逆バイアスが印加されると、ｐ+ｎ+接合領域に電界がかかり、トンネル効果によってリーク電流が増大してしまう。一般的な太陽電池におけるｐｎ接合分離が発電時（順バイアス時）における正極電極及び負極電極の拡散層を介した導通を阻止するために行われるのに対し、本発明における後述するレーザー接合分離は更に逆バイアス時のリーク電流も低減する効果も併せ持っている。例えば、ｎ型基板を用いて、表面側にボロン拡散層（拡散層１２ｐ）、裏面側にリン拡散層（拡散層１２ｎ）を形成した太陽電池において、ｎ+層内でｎ型基板の露出（接合分離）が行われた場合、具体的には、表面最外周のエッジ領域（外周縁）や基板側端部、又は基板裏面外周縁でｎ型基板を露出させたとしても、表面の拡散層１２ｐ側にｐ+ｎ+接合領域が存在しており、受光面外周縁領域のｐ+層に接したｎ+層にはｎ型基板を介して電圧がかかるため、ｐ+ｎ+接合領域に逆バイアスが印加されてリーク電流を発生させてしまう。
ここで、本発明者らはこの問題を解決すべく種々検討したところ、両面に拡散層を有する太陽電池においてｐ+ｎ+接合領域に逆バイアスが印加されないようにする方法として、表面拡散層（エミッタ層）の領域内に接合分離の溝を形成し、該拡散層とは逆の導電型の基板を露出させることで電極に接続したエミッタ層からの逆バイアスの電圧印加を防止することが重要であることを見出し、鋭意検討を行い、本発明を成すに至った。
即ち、本発明では下記のレーザー接合分離工程の処理を行う。By the way, the diffusion layers 12p and 12n formed on both surfaces of the substrate 10n are not formed only on desired surfaces in the diffusion heat treatment. For example, when boron diffusion is performed on the front surface side, a boron diffusion layer is also formed on the back surface side by boron autodoping. Further, even when phosphorus diffusion is performed on the back surface side, phosphorus auto-doping occurs on the front surface side, and a phosphorus diffusion layer is formed. As a result, the diffusion concentration of the phosphorus dopant is increased by the phosphorus dopant having a diffusion coefficient larger than that of the boron dopant in the substrate side end portion and the outer surface peripheral edge region. As shown in FIG. The concentration is compensated, and a high-concentration phosphorus diffusion layer (n + layer) 12n is continuously formed at the substrate side edge and the outer peripheral region of the surface (boron diffusion surface). This occurs even if a silicon oxide film for a mask is formed on the surface (boron diffusion surface) of the substrate. The width of the high-concentration phosphorous diffusion layer 12n in the outer peripheral region of the surface (boron diffusion surface) ranges from at least 0.08 mm to a maximum of 0.12 mm from the outer periphery by resistance measurement using a p-type substrate. It was confirmed that it was formed. Further, the width of the high concentration phosphorus diffusion layer 12n in the outer peripheral region of the surface (boron diffusion surface) is the same as that when the diffusion heat treatment is performed after the silicon oxide film for the mask is formed, and when the diffusing agent is applied to the two substrates 10n. It was almost the same as the case where the diffusion heat treatment was performed in a state where the first principal surfaces on which the layers were formed face each other and overlapped.
When a reverse bias is applied to this region in a state where the high-concentration phosphorus diffusion layer (n + layer) 12n is in contact with the high-concentration boron diffusion layer (p + layer) 12p (p + n + junction), p An electric field is applied to the + n + junction region, and the leakage current increases due to the tunnel effect. While pn junction separation in a general solar cell is performed to prevent conduction through the diffusion layer of the positive electrode and the negative electrode during power generation (forward bias), laser junction separation described later in the present invention is performed. In addition, it has the effect of reducing the leakage current during reverse bias. For example, in a solar cell in which a boron diffusion layer (diffusion layer 12p) is formed on the front side and a phosphorus diffusion layer (diffusion layer 12n) is formed on the back side using an n-type substrate, the n-type substrate is exposed in the n + layer ( Specifically, when the n-type substrate is exposed at the edge region (outer peripheral edge) on the outermost surface of the surface, the substrate side edge, or the outer peripheral edge of the back surface of the substrate, Since a p + n + junction region exists on the 12p side and a voltage is applied to the n + layer in contact with the p + layer in the outer peripheral edge region of the light receiving surface through the n-type substrate, the p + n + junction region A reverse bias is applied and a leak current is generated.
Here, the present inventors have made various studies to solve this problem. As a method for preventing a reverse bias from being applied to the p + n + junction region in a solar cell having diffusion layers on both sides, the surface diffusion layer ( It is important to prevent reverse bias voltage application from the emitter layer connected to the electrode by forming a junction isolation groove in the emitter layer region and exposing the substrate of the opposite conductivity type to the diffusion layer As a result, they have intensively studied to arrive at the present invention.
That is, in the present invention, the following laser bonding separation process is performed.

［レーザー接合分離工程］
本工程では、基板１０ｎの表面の該基板１０ｎとは逆の導電型の拡散層（拡散層１２ｐ）の外周縁部に沿ってレーザー照射して該拡散層１２ｐの外周縁部より内側の部分（及びその部分の反射防止膜兼パッシベーション膜１３を含む）を除去し、基板１０ｎの表面と裏面とを電気的に分離する接合分離溝１５を形成する（図３（ｄ））。[Laser bonding separation process]
In this step, laser irradiation is performed along the outer peripheral edge portion of the diffusion layer (diffusion layer 12p) having a conductivity type opposite to that of the substrate 10n on the surface of the substrate 10n, and a portion inside the outer peripheral edge portion of the diffusion layer 12p ( And the portion including the antireflection film / passivation film 13) are removed, and a junction separation groove 15 for electrically separating the front surface and the back surface of the substrate 10n is formed (FIG. 3D).

接合分離溝１５の形成は処理タクトが非常に短いレーザー加工技術を用いることで、安定した加工精度が得られ、低コスト化することが可能となる。
即ち、本工程で利用するレーザー加工に関し、レーザー媒体が固体であるものを固体レーザーといい、高ピーク強度パルスが得られることにより、広く工業用加工レーザーとして利用されている。その中で、クロムイオンをサファイア結晶に混入させたルビーレーザーやネオジウムイオンをＹＡＧ（イットリウム・アルミニウム・ガーネット結晶）に入れたＹＡＧレーザー（正確にはＮｄ：ＹＡＧレーザーと記述する）が代表的であり、ＹＡＧレーザーは波長が１０６４ｎｍの光（赤外線）を発するが、非線形光学結晶を用いて高調波を発生させることによって、波長５３２ｎｍの緑色の光や波長３５５ｎｍの紫外線なども出すことができるようになっている。波長５３２ｎｍのグリーンレーザーの光エネルギーはｅＶ＝１２３８．９／λの式より、ｅＶ＝２．３３であるので、シリコンのバンドギャップ１．１ｅＶの２倍以上のエネルギーを持っており、シリコン基板の加工を行うには十分な光エネルギーである。The formation of the junction separation groove 15 uses a laser processing technique with a very short processing tact, so that stable processing accuracy can be obtained and the cost can be reduced.
That is, regarding laser processing used in this step, a solid laser medium is called a solid laser, and is widely used as an industrial processing laser because a high peak intensity pulse can be obtained. Typical examples include ruby lasers in which chromium ions are mixed into sapphire crystals and YAG lasers in which neodymium ions are put into YAG (yttrium, aluminum, garnet crystals) (exactly described as Nd: YAG laser). The YAG laser emits light (infrared light) having a wavelength of 1064 nm. By generating harmonics using a nonlinear optical crystal, green light having a wavelength of 532 nm and ultraviolet light having a wavelength of 355 nm can be emitted. ing. Since the light energy of the green laser with a wavelength of 532 nm is eV = 2.33 from the equation of eV = 1238.9 / λ, it has energy more than twice the silicon band gap of 1.1 eV. The light energy is sufficient for processing.

シリコンはＹＡＧレーザーの基本波（１０６４ｎｍ）ではいくらか光が透過するのに対し、ＳＨＧ（Ｓｅｃｏｎｄ Ｈａｒｍｏｎｉｃ Ｇｅｎｅｒａｔｉｏｎ：第２高調波発生）−ＹＡＧレーザー（波長５３２ｎｍ）の光はほぼ完全に表面で吸収するという特性を持つことから、シリコン基板（基板１０ｎ）の表面加工を行うにあたり、ＳＨＧ−ＹＡＧレーザーを用いれば溶融表面での光吸収と蒸発が同時に起こり，内部デバイスに損傷を与えることなく表面スクライビングが可能となる。   Silicon transmits some light at the fundamental wave of a YAG laser (1064 nm), whereas light from a SHG (Second Harmonic Generation) -YAG laser (wavelength of 532 nm) is almost completely absorbed by the surface. Because of its characteristics, when using a SHG-YAG laser for surface processing of a silicon substrate (substrate 10n), light absorption and evaporation occur simultaneously on the molten surface, enabling surface scribing without damaging internal devices. It becomes.

また、代表的なＮｄ：ＹＡＧ固体レーザーは高出力が得られるものの、最大繰り返し周波数が５０ｋＨｚ程度と低く、高速な加工用途には限界がある。これに対してＮｄ：ＹＶＯ4レーザーは高い繰り返し周波数５０〜２００ｋＨｚが可能で、薄膜のスクライビング、切断、基板の穴あけ等の高速加工用に期待されている。高出力・高ピーク強度でのレーザー加工が幅広い繰り返し周波数で可能になり、高速走査でのレーザー加工が実現できる。Moreover, although a typical Nd: YAG solid-state laser can obtain a high output, the maximum repetition frequency is as low as about 50 kHz, and there is a limit to high-speed processing applications. On the other hand, the Nd: YVO 4 laser is capable of a high repetition frequency of 50 to 200 kHz, and is expected for high-speed processing such as scribing a thin film, cutting, and drilling a substrate. Laser processing with high output and high peak intensity is possible with a wide range of repetition frequencies, and laser processing with high-speed scanning can be realized.

上述のようにレーザーには他にも様々な種類があるが、シリコン表面のスクライビング現象に必要なエネルギーと時間幅に対応するレーザー光をシリコン基板に照射することによって目的とする形状の接合分離溝１５を形成することができる。   As described above, there are various other types of lasers. By irradiating the silicon substrate with laser light corresponding to the energy and time width required for the silicon surface scribing phenomenon, the junction separation groove having the desired shape is obtained. 15 can be formed.

ここで、図４に示すように、接合分離溝１５を基板１０ｎの表面において、溝幅の中心が表面外周縁から好ましくは０．１５ｍｍ以上０．６０ｍｍ以下、より好ましくは０．２ｍｍ以上０．４ｍｍ以下の距離Ｄだけ内側に入った領域内で基板外周縁に沿って表面電極（即ち、フィンガー電極１６ｆ及びバスバー電極１６ｂ）よりも外側に連続的に形成するとよい。   Here, as shown in FIG. 4, the center of the groove width is preferably 0.15 mm or more and 0.60 mm or less, more preferably 0.2 mm or more and 0.0. It may be formed continuously outside the surface electrodes (that is, the finger electrodes 16f and the bus bar electrodes 16b) along the outer peripheral edge of the substrate in a region that enters inside by a distance D of 4 mm or less.

また、基板１０ｎの表面における接合分離溝１５形成用に照射するレーザー光の走査パターンとしては、図５に示すように、基板１０ｎの表面外周縁から一定距離Ｄだけ内側に入った位置を一筆書きのようにその外周縁に沿ってレーザーを走査してもよい。あるいは、レーザー光の他の走査パターンとしては、図６に示すように、矩形の基板１０ｎの一辺ごとにその一辺の表面外周縁から一定距離Ｄだけ内側に入った位置をその辺の端から端まで該外周縁に沿ってレーザーを走査するようにし、これを４辺すべてにおいて行うようにしてもよい。   In addition, as shown in FIG. 5, the scanning pattern of the laser beam irradiated for forming the junction separation groove 15 on the surface of the substrate 10n is drawn with a single stroke from the outer peripheral edge of the surface of the substrate 10n by a certain distance D. The laser may be scanned along the outer peripheral edge as shown in FIG. Alternatively, as another scanning pattern of laser light, as shown in FIG. 6, a position that is located inward by a certain distance D from the outer peripheral edge of one side of each side of the rectangular substrate 10 n is end-to-end. Alternatively, the laser may be scanned along the outer peripheral edge, and this may be performed on all four sides.

また、接合分離溝１５の溝幅が好ましくは５〜３０μｍ、より好ましくは１０〜２０μｍであり、溝深さが好ましくは５〜３０μｍ、より好ましくは１０〜２０μｍであることが好ましい。接合分離溝１５の幅及び深さが上記下限を下回ると電気的な分離が不十分となるおそれがあり、上限を上回ると基板のチッピングが増えたり、基板が割れ易くなる場合がある。   Further, the groove width of the bonding separation groove 15 is preferably 5 to 30 μm, more preferably 10 to 20 μm, and the groove depth is preferably 5 to 30 μm, more preferably 10 to 20 μm. If the width and depth of the junction separation groove 15 are below the lower limit, electrical separation may be insufficient. If the width and depth are higher than the upper limit, chipping of the substrate may increase or the substrate may be easily broken.

このレーザー接合分離工程は、上記シリコン基板の表面及び裏面に拡散層１２ｐ、１２ｎを形成する工程の後、例えば拡散層１２ｐ、１２ｎ形成工程直後、反射防止膜兼パッシベーション膜１３、１４形成工程後、電極形成工程後に実施することが好ましい。   This laser junction separation step is performed after the step of forming the diffusion layers 12p and 12n on the front and back surfaces of the silicon substrate, for example, immediately after the step of forming the diffusion layers 12p and 12n, after the step of forming the antireflection film and passivation films 13 and 14, It is preferable to carry out after the electrode forming step.

［電極形成工程］
次いで、基板１０ｎの表裏面の反射防止膜兼パッシベーション膜１３、１４上にバスバー電極１６ｂ及びフィンガー電極１６ｆからなる表面電極１６とバスバー電極１７ｂ及びフィンガー電極１７ｆからなる裏面電極１７とを（図３ではフィンガー電極１６ｆ、１７ｆ）は不図示）スクリーン印刷法で形成する（図３（ｅ））。即ち、上記基板１０ｎの表裏面に、Ａｇ粉末とガラスフリットを有機物バインダと混合したＡｇペーストを印刷して乾燥し、電極印刷の後、熱処理によりＳｉＮｘ膜の反射防止膜兼パッシベーション膜１３、１４にＡｇ粉末を貫通させ（ファイヤースルー）、電極１６、１７とシリコン基板（拡散層１２ｐ、１２ｎ）とを導通させる。焼成は、通常７００〜８００℃の温度で５〜３０分間処理することで行われる。電極１６、１７の焼成は一度に行ってもよいし、各面の印刷後それぞれに焼成することも可能である。[Electrode formation process]
Next, the surface electrode 16 composed of the bus bar electrode 16b and the finger electrode 16f and the back surface electrode 17 composed of the bus bar electrode 17b and the finger electrode 17f on the antireflection film and passivation films 13 and 14 on the front and back surfaces of the substrate 10n (in FIG. 3). The finger electrodes 16f and 17f) are formed by screen printing (not shown) (FIG. 3E). That is, an Ag paste obtained by mixing Ag powder and glass frit with an organic binder is printed on the front and back surfaces of the substrate 10n and dried. After electrode printing, the SiNx film is formed into an antireflection film and a passivation film 13 and 14 by heat treatment. Ag powder is penetrated (fire through), and the electrodes 16 and 17 are electrically connected to the silicon substrate (diffusion layers 12p and 12n). Firing is usually performed by treating at a temperature of 700 to 800 ° C. for 5 to 30 minutes. The electrodes 16 and 17 may be fired at once, or may be fired after printing each surface.

以上、導電型がｎ型のシリコン基板（半導体基板１０ｎ）の場合を例にとって説明したが、基板の導電型がｐ型の場合でも、上記の拡散層に関するｐ型とｎ型の条件を入れ替えるようにすれば、本発明の製造方法が適用可能である。即ち、この場合には拡散層形成工程において、半導体基板１０ｐの表面にｎ型の拡散層１２ｎを形成し、裏面にｐ型の拡散層１２ｐを形成する。次いで、この工程以降に行われるレーザー接合分離工程において、半導体基板１０ｐの表面の該基板１０ｐとは逆の導電型の拡散層（拡散層１２ｎ）の外周縁部に沿ってレーザー照射して該拡散層１２ｎの外周縁部より内側の部分（及びその部分の反射防止膜兼パッシベーション膜１３を含む）を除去し、基板１０ｐの表面と裏面とを電気的に分離する接合分離溝１５を形成する。この場合のレーザー接合分離の条件は上述したものと同じでよい。   The case where the conductivity type is a silicon substrate (semiconductor substrate 10n) has been described above as an example. However, even when the conductivity type of the substrate is p-type, the p-type and n-type conditions regarding the diffusion layer are switched. If so, the manufacturing method of the present invention is applicable. That is, in this case, in the diffusion layer forming step, the n-type diffusion layer 12n is formed on the front surface of the semiconductor substrate 10p, and the p-type diffusion layer 12p is formed on the back surface. Next, in a laser junction separation process performed after this process, the diffusion is performed by irradiating a laser along the outer peripheral edge of a diffusion layer (diffusion layer 12n) having a conductivity type opposite to that of the substrate 10p on the surface of the semiconductor substrate 10p. A portion inside the outer peripheral edge portion of the layer 12n (and the antireflection film / passivation film 13 in that portion) is removed, and a junction separation groove 15 for electrically separating the front surface and the back surface of the substrate 10p is formed. The laser bonding / separation conditions in this case may be the same as those described above.

具体的には、図７に示すように、接合分離溝１５を基板１０ｐの表面において溝幅の中心が表面外周縁から好ましくは０．１５ｍｍ以上０．６０ｍｍ以下、より好ましくは０．２ｍｍ以上０．４ｍｍ以下の距離Ｄだけ内側に入った領域内で基板外周縁に沿って表面電極（即ち、フィンガー電極１６ｆ及びバスバー電極１６ｂ）よりも外側に連続的に形成するとよい。   Specifically, as shown in FIG. 7, the center of the groove width of the junction separation groove 15 on the surface of the substrate 10p is preferably from 0.15 mm to 0.60 mm, more preferably from 0.2 mm to 0. It may be formed continuously outside the surface electrodes (that is, the finger electrodes 16f and the bus bar electrodes 16b) along the outer peripheral edge of the substrate within a region that is inside by a distance D of 4 mm or less.

また、基板１０ｐの表面における接合分離溝１５形成用に照射するレーザー光の走査パターンとしては、図８に示すように、基板１０ｐの表面外周縁から一定距離Ｄだけ内側に入った位置を一筆書きのようにその外周縁に沿ってレーザーを走査してもよい。あるいは、レーザー光の他の走査パターンとしては、図９に示すように、矩形の基板１０ｐの一辺ごとにその一辺の表面外周縁から一定距離Ｄだけ内側に入った位置をその辺の端から端まで該外周縁に沿ってレーザーを走査するようにし、これを４辺すべてにおいて行うようにしてもよい。   In addition, as shown in FIG. 8, the scanning pattern of the laser beam irradiated for forming the junction separation groove 15 on the surface of the substrate 10p is drawn with a single stroke from the outer periphery of the surface of the substrate 10p by a certain distance D. The laser may be scanned along the outer peripheral edge as shown in FIG. Alternatively, as another scanning pattern of laser light, as shown in FIG. 9, a position that is located at a certain distance D from the outer periphery of the surface of one side of each side of the rectangular substrate 10 p is end-to-end. Alternatively, the laser may be scanned along the outer peripheral edge, and this may be performed on all four sides.

以上のように、レーザー接合分離を行うことにより、逆バイアス時のリーク電流の少ない高効率の両面受光型の太陽電池を歩留まりよく作製することができる。   As described above, by performing laser junction separation, a high-efficiency double-sided light-receiving solar cell with little leakage current at the time of reverse bias can be manufactured with high yield.

以下に本発明の実施例を挙げて具体的に説明するが、本発明はこれらに限定されるものではない。   Examples of the present invention will be specifically described below, but the present invention is not limited thereto.

［実施例１］
＜太陽電池の製造＞
上記レーザー接合分離を含む本発明の太陽電池の製造方法で、以下のようにｎ型基板を用いて太陽電池を製造した。
結晶面方位（１００）、１５．６ｃｍ角２００μｍ厚、アズスライス比抵抗２Ω・ｃｍ（ドーパント濃度７．２×１０15ｃｍ-3）リンドープｎ型単結晶シリコン基板を、水酸化ナトリウム水溶液に浸してダメージ層をエッチングで取り除き、水酸化カリウム水溶液にイソプロピルアルコールを加えた水溶液に浸してアルカリエッチングすることでテクスチャ形成を行った。得られたシリコン基板全体を１，０００℃、１時間熱処理してシリコン酸化膜を形成した。次に、裏面のシリコン酸化膜をふっ酸等の薬液を用いて除去し、裏面にリンドーパントを含む塗布剤を塗布した後に、９５０℃、１時間熱処理を行い、ｎ型拡散層を裏面に形成した。熱処理後、基板に付いたガラス成分はふっ酸溶液等により除去後、洗浄した。
再度、シリコン基板全体にシリコン酸化膜を形成し、表面のシリコン酸化膜をふっ酸等の薬液を用いて除去し、表面にボロンドーパントを含む塗布剤を塗布した後に、９５０℃、１時間熱処理を行い、ｐ型拡散層を表面全体に形成した。
次に、基板に付いたガラス成分を高濃度ふっ酸溶液等により除去後、洗浄した。
引き続き、ダイレクトプラズマＣＶＤ装置を用い、シリコン基板の表面及び裏面に反射防止膜兼パッシベーション膜であるシリコン窒化膜を積層した。この膜厚は７０ｎｍであった。
ここで、波長５３２ｎｍのＹＶＯ4レーザーを用いて、表面外周縁から内側に０．１５ｍｍ入った領域の反射防止膜兼パッシベーション膜及びｐ型拡散層の外周縁部近傍を除去して幅２０μｍ、深さ１０μｍの接合分離溝を表面外周縁に沿って連続的に形成した。レーザー照射の条件は、繰り返し周波数１００ｋＨｚ、出力１０．６Ｗ、スキャンスピード１，０００ｍｍ／ｓｅｃで行った。
表面側及び裏面側にそれぞれ銀ペーストをスクリーン印刷法により電極印刷し、乾燥後８００℃で２０分間焼成を行い、表面電極及び裏面電極を形成した。この場合、焼成中に銀ペースト中のガラスフリットが反射防止膜兼パッシベーション膜をファイヤースルーすることにより、電極と拡散層との電気的な導通が達成される。[Example 1]
<Manufacture of solar cells>
In the solar cell manufacturing method of the present invention including the laser junction separation, a solar cell was manufactured using an n-type substrate as follows.
Crystal plane orientation (100), 15.6 cm square 200 μm thickness, as-slice specific resistance 2 Ω · cm (dopant concentration 7.2 × 10 15 cm −3 ) Phosphorus-doped n-type single crystal silicon substrate is immersed in an aqueous sodium hydroxide solution The damaged layer was removed by etching, and texture formation was performed by soaking in an aqueous solution obtained by adding isopropyl alcohol to an aqueous potassium hydroxide solution and performing alkali etching. The entire obtained silicon substrate was heat-treated at 1,000 ° C. for 1 hour to form a silicon oxide film. Next, the silicon oxide film on the back surface is removed using a chemical solution such as hydrofluoric acid, and a coating agent containing a phosphorus dopant is applied to the back surface, followed by heat treatment at 950 ° C. for 1 hour to form an n-type diffusion layer on the back surface. did. After the heat treatment, glass components attached to the substrate were removed with a hydrofluoric acid solution and then washed.
Again, a silicon oxide film is formed on the entire silicon substrate, the surface silicon oxide film is removed using a chemical solution such as hydrofluoric acid, and a coating agent containing boron dopant is applied to the surface, followed by heat treatment at 950 ° C. for 1 hour. A p-type diffusion layer was formed on the entire surface.
Next, the glass component attached to the substrate was removed with a high-concentration hydrofluoric acid solution and then washed.
Subsequently, a silicon nitride film, which is an antireflection film and a passivation film, was stacked on the front and back surfaces of the silicon substrate using a direct plasma CVD apparatus. This film thickness was 70 nm.
Here, by using a YVO 4 laser having a wavelength of 532 nm, the antireflection film / passivation film in the region 0.15 mm inward from the outer periphery of the surface and the vicinity of the outer periphery of the p-type diffusion layer are removed to obtain a width of 20 μm and a depth of A bonding separation groove having a thickness of 10 μm was continuously formed along the outer peripheral edge of the surface. The laser irradiation was performed at a repetition frequency of 100 kHz, an output of 10.6 W, and a scan speed of 1,000 mm / sec.
A silver paste was electrode-printed on each of the front side and the rear side by screen printing, dried, and baked at 800 ° C. for 20 minutes to form a front electrode and a back electrode. In this case, the glass frit in the silver paste fires through the antireflection film / passivation film during firing to achieve electrical conduction between the electrode and the diffusion layer.

［実施例２］
接合分離溝を表面外周縁から内側に０．３０ｍｍ入った領域に形成したこと以外は実施例１と同様の工程で太陽電池を作製した。[Example 2]
A solar cell was fabricated in the same manner as in Example 1 except that the junction separation groove was formed in a region 0.30 mm inward from the outer peripheral edge of the surface.

［実施例３］
接合分離溝を表面外周縁から内側に０．６０ｍｍ入った領域に形成したこと以外は実施例１と同様の工程で太陽電池を作製した。[Example 3]
A solar cell was fabricated in the same process as in Example 1 except that the junction separation groove was formed in an area of 0.60 mm inside from the outer peripheral edge of the surface.

［参考例］
参考のため、接合分離溝を表面外周縁から内側に０．８０ｍｍ入った領域に形成したこと以外は実施例１と同様の工程で太陽電池を作製した。[Reference example]
For reference, a solar cell was produced in the same process as in Example 1 except that the junction separation groove was formed in a region 0.80 mm inside from the outer peripheral edge of the surface.

［比較例１］
比較のため、図１０に示すように、接合分離溝を表面外周縁から内側に０．１０ｍｍ入った領域に形成したこと以外は実施例１と同様の工程で太陽電池を作製した。[Comparative Example 1]
For comparison, as shown in FIG. 10, a solar cell was manufactured in the same process as in Example 1 except that the junction separation groove was formed in a region having a depth of 0.10 mm inside from the outer peripheral edge of the surface.

［比較例２］
比較のため、図１１に示すように、接合分離溝を裏面外周縁から内側に０．２０ｍｍ入った領域に形成したこと以外は実施例１と同様の工程で太陽電池を作製した。[Comparative Example 2]
For comparison, as shown in FIG. 11, a solar cell was manufactured in the same process as in Example 1 except that the junction separation groove was formed in a region 0.20 mm inward from the outer peripheral edge of the back surface.

［比較例３］
比較のため、図１２に示すように、表面側及び裏面側のどちらにも接合分離溝を形成しなかった場合の太陽電池を作製した。接合分離以外の他の工程は実施例１と同様の処理を行った。[Comparative Example 3]
For comparison, as shown in FIG. 12, a solar cell was produced in the case where no junction separation groove was formed on either the front surface side or the back surface side. The same processes as in Example 1 were performed in the other processes other than the junction separation.

［比較例４］
更に比較のため、図１３に示すように、プラズマエッチングによって基板側端部を接合分離した場合の太陽電池を作製した。具体的には、拡散熱処理により両面に拡散層を形成した基板をプラズマやラジカルが表面や裏面に侵入しないようにスタックし、ＣＦ4ガスを用いたプラズマエッチング処理を行って基板の側端部を数μｍ削った。接合分離以外の他の工程は実施例１と同様の処理を行った。[Comparative Example 4]
Further, for comparison, as shown in FIG. 13, a solar cell was manufactured in the case where the substrate side end portion was separated by plasma etching. Specifically, a substrate having a diffusion layer formed on both sides by diffusion heat treatment is stacked so that plasma and radicals do not enter the front and back surfaces, and a plasma etching process using CF 4 gas is performed to remove the side edges of the substrate. A few μm was shaved. The same processes as in Example 1 were performed in the other processes other than the junction separation.

［実施例４］
＜太陽電池の製造＞
上記レーザー接合分離を含む本発明の太陽電池の製造方法で、以下のようにｐ型基板を用いて太陽電池を製造した。
結晶面方位（１００）、１５．６ｃｍ角２００μｍ厚、アズスライス比抵抗２Ω・ｃｍ（ドーパント濃度７．２×１０15ｃｍ-3）ボロンドープｐ型単結晶シリコン基板を、水酸化ナトリウム水溶液に浸してダメージ層をエッチングで取り除き、水酸化カリウム水溶液にイソプロピルアルコールを加えた水溶液に浸してアルカリエッチングすることでテクスチャ形成を行った。得られたシリコン基板全体を１，０００℃、１時間熱処理してシリコン酸化膜を形成した。次に、表面のシリコン酸化膜をふっ酸等の薬液を用いて除去し、表面側にリンドーパントを含む塗布剤を塗布した後に、９５０℃、１時間熱処理を行い、ｎ型拡散層を表面側に形成した。熱処理後、基板に付いたガラス成分はふっ酸溶液等により除去後、洗浄した。
再度、シリコン基板全体にシリコン酸化膜を形成し、裏面側のシリコン酸化膜をふっ酸等の薬液を用いて除去し、裏面側にボロンドーパントを含む塗布剤を塗布した後に、９５０℃、１時間熱処理を行い、ｐ型拡散層を裏面側に形成した。
次に、基板に付いたガラス成分を高濃度ふっ酸溶液等により除去後、洗浄した。
引き続き、ダイレクトプラズマＣＶＤ装置を用い、シリコン基板の表面及び裏面に反射防止膜兼パッシベーション膜であるシリコン窒化膜を積層した。この膜厚は７０ｎｍであった。
ここで、波長５３２ｎｍのＹＶＯ4レーザーを用いて、表面外周縁から０．１０ｍｍ内側に入った領域の反射防止膜兼パッシベーション膜及びｎ型拡散層の外周縁部近傍を除去して幅２０μｍ、深さ１０μｍの接合分離溝を基板の外周縁に沿って連続的に形成した。レーザー照射の条件は、繰り返し周波数５０ｋＨｚ、出力１２．５Ｗ、スキャンスピード１，０００ｍｍ／ｓｅｃで行った。
表面側及び裏面側にそれぞれ銀ペーストをスクリーン印刷法により電極印刷し、乾燥後８００℃で２０分間焼成を行い、表面電極及び裏面電極を形成した。この場合、焼成中に銀ペースト中のガラスフリットが反射防止膜兼パッシベーション膜をファイヤースルーすることにより、電極と拡散層との電気的な導通が達成される。[Example 4]
<Manufacture of solar cells>
In the solar cell manufacturing method of the present invention including the laser junction separation, a solar cell was manufactured using a p-type substrate as follows.
Crystal plane orientation (100), 15.6 cm square 200 μm thickness, as-slice specific resistance 2 Ω · cm (dopant concentration 7.2 × 10 15 cm −3 ) Boron-doped p-type single crystal silicon substrate is immersed in an aqueous sodium hydroxide solution The damaged layer was removed by etching, and texture formation was performed by soaking in an aqueous solution obtained by adding isopropyl alcohol to an aqueous potassium hydroxide solution and performing alkali etching. The entire obtained silicon substrate was heat-treated at 1,000 ° C. for 1 hour to form a silicon oxide film. Next, after removing the silicon oxide film on the surface using a chemical solution such as hydrofluoric acid and applying a coating agent containing a phosphorus dopant on the surface side, heat treatment is performed at 950 ° C. for 1 hour, and the n-type diffusion layer is formed on the surface side. Formed. After the heat treatment, glass components attached to the substrate were removed with a hydrofluoric acid solution and then washed.
Again, a silicon oxide film is formed on the entire silicon substrate, the silicon oxide film on the back side is removed using a chemical solution such as hydrofluoric acid, and a coating agent containing boron dopant is applied on the back side, and then at 950 ° C. for 1 hour. Heat treatment was performed to form a p-type diffusion layer on the back side.
Next, the glass component attached to the substrate was removed with a high-concentration hydrofluoric acid solution and then washed.
Subsequently, a silicon nitride film, which is an antireflection film and a passivation film, was stacked on the front and back surfaces of the silicon substrate using a direct plasma CVD apparatus. This film thickness was 70 nm.
Here, by using a YVO 4 laser having a wavelength of 532 nm, the antireflection film / passivation film and the vicinity of the outer peripheral edge of the n-type diffusion layer in the region 0.10 mm inside from the outer peripheral edge of the surface are removed to obtain a width of 20 μm and a depth of 20 μm. A 10 μm thick junction separation groove was continuously formed along the outer peripheral edge of the substrate. The laser irradiation was performed at a repetition frequency of 50 kHz, an output of 12.5 W, and a scan speed of 1,000 mm / sec.
A silver paste was electrode-printed on each of the front side and the rear side by screen printing, dried, and baked at 800 ° C. for 20 minutes to form a front electrode and a back electrode. In this case, the glass frit in the silver paste fires through the antireflection film / passivation film during firing to achieve electrical conduction between the electrode and the diffusion layer.

［実施例５］
接合分離溝を表面外周縁から内側に０．２０ｍｍ入った領域に形成したこと以外は実施例４と同様の工程で太陽電池を作製した。[Example 5]
A solar cell was produced in the same process as in Example 4 except that the junction separation groove was formed in a region 0.20 mm inward from the outer peripheral edge of the surface.

［実施例６］
接合分離溝を表面外周縁から内側に０．３０ｍｍ入った領域に形成したこと以外は実施例４と同様の工程で太陽電池を作製した。[Example 6]
A solar cell was produced in the same process as in Example 4 except that the junction separation groove was formed in a region 0.30 mm inward from the outer peripheral edge of the surface.

［比較例５］
比較のため、接合分離溝を裏面外周縁から内側に０．１０ｍｍ入った領域に形成したこと以外は実施例４と同様の工程で太陽電池を作製した。[Comparative Example 5]
For comparison, a solar cell was fabricated in the same process as in Example 4 except that the junction separation groove was formed in a region having an inner diameter of 0.10 mm from the outer peripheral edge of the back surface.

［比較例６］
比較のため、接合分離溝を裏面外周縁から内側に０．２０ｍｍ入った領域に形成したこと以外は実施例４と同様の工程で太陽電池を作製した。[Comparative Example 6]
For comparison, a solar cell was fabricated in the same process as in Example 4 except that the junction separation groove was formed in a region 0.20 mm inward from the outer peripheral edge of the back surface.

［比較例７］
比較のため、接合分離溝を裏面外周縁から内側に０．３０ｍｍ入った領域に形成したこと以外は実施例４と同様の工程で太陽電池を作製した。[Comparative Example 7]
For comparison, a solar cell was fabricated in the same process as in Example 4 except that the junction separation groove was formed in a region 0.30 mm inward from the outer peripheral edge of the back surface.

［比較例８］
比較のため、表面側及び裏面側のどちらにも接合分離溝を形成しなかった場合の太陽電池を作製した。接合分離以外の他の工程は実施例４と同様の処理を行った。[Comparative Example 8]
For comparison, a solar cell was produced when no junction separation groove was formed on either the front surface side or the back surface side. The same processes as in Example 4 were performed in the steps other than the junction separation.

［比較例９］
更に比較のため、プラズマエッチングによって基板側端部を接合分離した場合の太陽電池を作製した。具体的には、拡散熱処理により両面に拡散層を形成した基板をプラズマやラジカルが表面や裏面に侵入しないようにスタックし、ＣＦ4ガスを用いたプラズマエッチング処理を行って基板の側端部を数μｍ削った。接合分離以外の他の工程は実施例４と同様の処理を行った。
以上の実施例、参考例及び比較例の接合分離条件を表１に示す。[Comparative Example 9]
Further, for comparison, a solar cell was manufactured in the case where the substrate side end portion was separated by plasma etching. Specifically, a substrate having a diffusion layer formed on both sides by diffusion heat treatment is stacked so that plasma and radicals do not enter the front and back surfaces, and a plasma etching process using CF 4 gas is performed to remove the side edges of the substrate. A few μm was shaved. The same processes as in Example 4 were performed in the steps other than the junction separation.
Table 1 shows the junction separation conditions of the above Examples, Reference Examples and Comparative Examples.

Figure 0006299757
Figure 0006299757

また、実施例、参考例及び比較例で得られた太陽電池を、２５℃の雰囲気の中、ソーラーシミュレータ（光強度：１ｋＷ／ｍ2，スペクトル：ＡＭ１．５グローバル）の下で電流電圧特性を測定した。更に、１２Ｖの逆バイアスを印加した際のリーク電流も測定した。接合分離に要する処理タクトを含めた結果を表２に示す。なお、表中の数字は実施例、参考例及び比較例で試作したセル１００枚の平均値である。In addition, the solar cells obtained in Examples, Reference Examples and Comparative Examples were subjected to current-voltage characteristics under a solar simulator (light intensity: 1 kW / m 2 , spectrum: AM1.5 global) in an atmosphere at 25 ° C. It was measured. Furthermore, the leakage current when a reverse bias of 12 V was applied was also measured. Table 2 shows the results including the processing tact required for joining and separation. In addition, the number in a table | surface is an average value of 100 cell made as an experiment by an Example, a reference example, and a comparative example.

Figure 0006299757
Figure 0006299757

上記表２の結果より、ｎ型基板に両面拡散層を有する太陽電池において、実施例１〜３で行われたレーザー接合分離は、比較例４のプラズマエッチング接合分離に対して、変換効率を維持しながらリーク電流を低減させることができた。比較例１及び２で行われたレーザー接合分離では、リーク電流が高かった。特に、比較例２は、接合分離溝を形成していない比較例３と同等の高いリーク電流値であった。ｎ型基板に両面拡散層を有する太陽電池では、裏面に接合分離溝を形成しても、逆バイアス時のリーク電流を低減させる効果はない。
更に、参考例の表面外周から０．８０ｍｍでレーザー接合分離した条件では、逆バイアス時のリーク電流は低かったが、変換効率が低下した。主に、有効な受光面積が減少したことによって、短絡電流が減少したことによる。ｎ型基板に両面拡散層を有する太陽電池における表面外周縁の接合分離溝は外周縁から内側に０．１５ｍｍ以上０．６０ｍｍ以下の距離だけ入った領域に形成することが好適であることを示唆している。
また、ｐ型基板に両面拡散層を有する太陽電池において、実施例４〜６で行われたレーザー接合分離は、比較例９のプラズマエッチング接合分離に対して、変換効率を維持しながらリーク電流を低減させることができた。表面側には均一なエミッタ層（ｎ+層）が形成されているため、任意の加工位置で接合分離溝を形成することができる。比較例５〜７で行われたレーザー接合分離では、リーク電流が高かった。特に、比較例６及び７は、接合分離溝を形成していない比較例８と同等の高いリーク電流値であった。ｐ型基板に両面拡散層を有する太陽電池では、裏面に接合分離溝を形成しても、逆バイアス時のリーク電流を低減させる効果はないか、又は小さい。
これらの結果から、半導体基板を用いて両面に拡散層を形成した太陽電池の作製に対して、表面外周縁領域のエミッタ層内におけるレーザーを用いた接合分離溝の形成が高変換効率維持とリーク電流低減に有効であり、高いスループットと共に低コスト化を実現することが可能となることを示唆している。From the results in Table 2 above, in the solar cell having the double-sided diffusion layer on the n-type substrate, the laser junction separation performed in Examples 1 to 3 maintains the conversion efficiency with respect to the plasma etching junction separation in Comparative Example 4. However, the leakage current could be reduced. In the laser junction separation performed in Comparative Examples 1 and 2, the leakage current was high. In particular, Comparative Example 2 had a high leakage current value equivalent to that of Comparative Example 3 in which no junction separation groove was formed. In a solar cell having a double-sided diffusion layer on an n-type substrate, even if a junction separation groove is formed on the back surface, there is no effect of reducing leakage current during reverse bias.
Furthermore, under the condition where the laser bonding was separated at 0.80 mm from the outer periphery of the surface of the reference example, the leakage current at the time of reverse bias was low, but the conversion efficiency was lowered. This is mainly due to a decrease in the short-circuit current due to a decrease in the effective light receiving area. In the solar cell having a double-sided diffusion layer on the n-type substrate, it is suggested that the junction separation groove on the outer periphery of the surface is preferably formed in a region having a distance of 0.15 mm or more and 0.60 mm or less inward from the outer periphery. doing.
Further, in the solar cell having the double-sided diffusion layer on the p-type substrate, the laser junction separation performed in Examples 4 to 6 has a leakage current while maintaining the conversion efficiency with respect to the plasma etching junction separation in Comparative Example 9. It was possible to reduce. Since a uniform emitter layer (n + layer) is formed on the surface side, a junction separation groove can be formed at an arbitrary processing position. In the laser junction separation performed in Comparative Examples 5 to 7, the leakage current was high. In particular, Comparative Examples 6 and 7 had a high leakage current value equivalent to that of Comparative Example 8 in which no junction separation groove was formed. In a solar cell having a double-sided diffusion layer on a p-type substrate, even if a junction separation groove is formed on the back surface, there is no or little effect of reducing the leakage current during reverse bias.
From these results, it can be seen that the formation of a junction separation groove using a laser in the emitter layer in the outer peripheral region of the surface is capable of maintaining high conversion efficiency and leaking in the manufacture of a solar cell in which a diffusion layer is formed on both sides using a semiconductor substrate. It is effective in reducing current and suggests that it is possible to realize low cost with high throughput.

更に、本発明は上記実施形態に限定されるものではない。上記実施形態は例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、如何なるものであっても本発明の技術範囲に包含される。   Furthermore, the present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration substantially the same as the technical idea described in the claims of the present invention and exhibits the same function and effect. It is included in the technical scope.

１０ｎ ｎ型半導体基板
１０ｐ ｐ型半導体基板
１２ｎ ｎ型拡散層（ｎ+拡散層）
１２ｐ ｐ型拡散層（ｐ+拡散層）
１３、１４ 反射防止膜兼パッシベーション膜
１５ 接合分離溝
１６ 表面電極
１６ｂ 表面バスバー電極（バスバー電極）
１６ｆ 表面フィンガー電極（フィンガー電極）
１７ 裏面電極
１７ｂ 裏面バスバー電極（バスバー電極）
１７ｆ 裏面フィンガー電極（フィンガー電極）10n n-type semiconductor substrate 10pp p-type semiconductor substrate 12n n-type diffusion layer (n + diffusion layer)
12p p-type diffusion layer (p + diffusion layer)
13, 14 Antireflection film / passivation film 15 Junction separation groove 16 Surface electrode 16b Surface bus bar electrode (bus bar electrode)
16f Surface finger electrode (finger electrode)
17 Back electrode 17b Back bus bar electrode (bus bar electrode)
17f Back finger electrode (finger electrode)

Claims (4)

ｎ型半導体基板の裏面を露出させ表面をシリコン酸化膜でマスクした状態で該裏面にｎ型ドーパントを含む拡散剤を塗布した後に熱処理してｎ型拡散層を形成する処理と、上記ｎ型半導体基板の表面を露出させそれ以外はシリコン酸化膜でマスクした状態で該表面にｐ型ドーパントを含む拡散剤を塗布した後に熱処理してｐ型拡散層を形成する処理とをこの順番で行って、又はｎ型半導体基板の表面にｐ型ドーパントを含む拡散剤を塗布し、この状態の２枚の基板の拡散剤を塗布した表面同士を向き合わせて重ね合わせた状態で拡散熱処理を行うと共にこの時にｎ型ドーパントを含むガスを導入して基板の裏面にｎ型拡散層を形成する処理と表面にｐ型拡散層を形成する処理とを同時に行って、基板の裏面、基板側端部及び表面の外周縁領域にｎ型拡散層が連続して形成され、表面の外周縁領域のｎ型拡散層よりも内側で該ｎ型拡散層に接するｐ型拡散層が形成されたｎ型半導体基板を得る工程と、上記ｎ型半導体基板の表面のｐ型拡散層の外周縁部に沿ってレーザー照射して該ｐ型拡散層の外周縁部より内側の部分の拡散層を除去し、基板表面のｐ型拡散層の領域においてｎ型半導体基板が露出した状態であって、ｎ型半導体基板の表面と裏面とを電気的に分離する接合分離部を形成する工程とを有することを特徴とする両面受光型の太陽電池の製造方法。 a process of forming an n-type diffusion layer by applying a diffusing agent containing an n-type dopant to the back surface in a state where the back surface of the n-type semiconductor substrate is exposed and the surface is masked with a silicon oxide film, and the n-type semiconductor In this order, the surface of the substrate is exposed and the p-type diffusion layer is formed by heat treatment after applying a diffusing agent containing a p-type dopant to the surface while masking with a silicon oxide film. Alternatively, a diffusion agent containing a p-type dopant is applied to the surface of the n-type semiconductor substrate, and diffusion heat treatment is performed in a state where the surfaces of the two substrates in this state applied with each other facing each other are overlapped. A process of forming an n-type diffusion layer on the back surface of the substrate by introducing a gas containing an n-type dopant and a process of forming a p-type diffusion layer on the front surface are performed at the same time. Outer peripheral area a step of obtaining an n-type semiconductor substrate in which an n-type diffusion layer is continuously formed and a p-type diffusion layer in contact with the n-type diffusion layer is formed on the inner side of the n-type diffusion layer in the outer peripheral region of the surface; Laser irradiation is performed along the outer peripheral edge of the p-type diffusion layer on the surface of the n-type semiconductor substrate to remove the diffusion layer inside the outer peripheral edge of the p-type diffusion layer, and the p-type diffusion layer on the substrate surface is removed. And a step of forming a junction separation portion that electrically separates the front surface and the back surface of the n-type semiconductor substrate in a state where the n-type semiconductor substrate is exposed in the region. Manufacturing method. ｐ型半導体基板の表面を露出させ裏面をシリコン酸化膜でマスクした状態で該表面にｎ型ドーパントを含む拡散剤を塗布した後に熱処理してｎ型拡散層を形成する処理と、上記ｐ型半導体基板の裏面を露出させそれ以外はシリコン酸化膜でマスクした状態で該裏面にｐ型ドーパントを含む拡散剤を塗布した後に熱処理してｐ型拡散層を形成する処理とをこの順番で行って、又はｐ型半導体基板の裏面にｐ型ドーパントを含む拡散剤を塗布し、この状態の２枚の基板の拡散剤を塗布した裏面同士を向き合わせて重ね合わせた状態で拡散熱処理を行うと共にこの時にｎ型ドーパントを含むガスを導入して基板の表面にｎ型拡散層を形成する処理と裏面にｐ型拡散層を形成する処理とを同時に行って、基板の表面、基板側端部及び裏面の外周縁領域にｎ型拡散層が連続して形成され、裏面の外周縁領域のｎ型拡散層よりも内側で該ｎ型拡散層に接するｐ型拡散層が形成されたｐ型半導体基板を得る工程と、上記ｐ型半導体基板の表面のｎ型拡散層の外周縁部に沿ってレーザー照射して該ｎ型拡散層の外周縁部より内側の部分の拡散層を除去し、基板表面のｎ型拡散層の領域においてｐ型半導体基板が露出した状態であって、ｐ型半導体基板の表面と裏面とを電気的に分離する接合分離部を形成する工程とを有することを特徴とする両面受光型の太陽電池の製造方法。 a process of forming an n-type diffusion layer by applying a diffusing agent containing an n-type dopant to the surface of the p-type semiconductor substrate with the front surface exposed and the back surface masked with a silicon oxide film; and the p-type semiconductor A process of forming a p-type diffusion layer in this order by applying a diffusing agent containing a p-type dopant to the back surface in a state where the back surface of the substrate is exposed and otherwise masked with a silicon oxide film, Alternatively, a diffusion agent containing a p-type dopant is applied to the back surface of the p-type semiconductor substrate, and diffusion heat treatment is performed while the back surfaces of the two substrates coated with the diffusing agent facing each other are overlapped with each other. A process of introducing a gas containing an n-type dopant to form an n-type diffusion layer on the surface of the substrate and a process of forming a p-type diffusion layer on the back surface are performed at the same time. Outer peripheral area a step of obtaining a p-type semiconductor substrate in which an n-type diffusion layer is continuously formed and a p-type diffusion layer in contact with the n-type diffusion layer is formed on the inner side of the n-type diffusion layer in the outer peripheral region of the back surface; Laser irradiation is performed along the outer peripheral edge of the n-type diffusion layer on the surface of the p-type semiconductor substrate to remove the diffusion layer inside the outer peripheral edge of the n-type diffusion layer, and the n-type diffusion layer on the surface of the substrate is removed. And a step of forming a junction separation part for electrically separating the front surface and the back surface of the p-type semiconductor substrate in a state where the p-type semiconductor substrate is exposed in the region. Manufacturing method. 接合分離部は、幅の中心が表面外周縁から０．１５ｍｍ以上０．６０ｍｍ以下の距離だけ内側に入った領域内で基板外周縁に沿って表面電極よりも外側に連続的に形成された溝であることを特徴とする請求項１又は２記載の太陽電池の製造方法。 The junction separation part is a groove formed continuously outside the surface electrode along the outer peripheral edge of the substrate in a region where the center of the width enters the inner side by a distance of 0.15 mm or more and 0.60 mm or less from the outer peripheral edge of the surface. method of manufacturing a solar cell according to claim 1 or 2, wherein the at. 接合分離部は、溝幅が５μｍ以上３０μｍ以下であり、溝深さが５μｍ以上３０μｍ以下の溝であることを特徴とする請求項１〜３のいずれか１項記載の太陽電池の製造方法。 Junction isolation portion is a groove width of 5 [mu] m or more 30μm or less, for producing a solar cell according to any one of claims 1-3, wherein the groove depth is 30μm or less grooves than 5 [mu] m.
JP2015518131A 2013-05-21 2014-03-24 Manufacturing method of solar cell Active JP6299757B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2013107203 2013-05-21
JP2013107203 2013-05-21
PCT/JP2014/058064 WO2014188773A1 (en) 2013-05-21 2014-03-24 Method for manufacturing solar cell, and solar cell

Publications (2)

Publication Number Publication Date
JPWO2014188773A1 JPWO2014188773A1 (en) 2017-02-23
JP6299757B2 true JP6299757B2 (en) 2018-03-28

Family

ID=51933339

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2015518131A Active JP6299757B2 (en) 2013-05-21 2014-03-24 Manufacturing method of solar cell

Country Status (3)

Country Link
JP (1) JP6299757B2 (en)
TW (1) TWI624078B (en)
WO (1) WO2014188773A1 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109463019B (en) 2016-06-13 2022-06-24 信越化学工业株式会社 Solar cell and manufacturing method thereof
US11282815B2 (en) 2020-01-14 2022-03-22 Micron Technology, Inc. Methods of forming microelectronic devices, and related microelectronic devices and electronic systems
US11380669B2 (en) * 2020-06-18 2022-07-05 Micron Technology, Inc. Methods of forming microelectronic devices
US11699652B2 (en) 2020-06-18 2023-07-11 Micron Technology, Inc. Microelectronic devices and electronic systems
US11563018B2 (en) 2020-06-18 2023-01-24 Micron Technology, Inc. Microelectronic devices, and related methods, memory devices, and electronic systems
US11557569B2 (en) 2020-06-18 2023-01-17 Micron Technology, Inc. Microelectronic devices including source structures overlying stack structures, and related electronic systems
US11705367B2 (en) 2020-06-18 2023-07-18 Micron Technology, Inc. Methods of forming microelectronic devices, and related microelectronic devices, memory devices, electronic systems, and additional methods
US11417676B2 (en) 2020-08-24 2022-08-16 Micron Technology, Inc. Methods of forming microelectronic devices and memory devices, and related microelectronic devices, memory devices, and electronic systems
US11825658B2 (en) 2020-08-24 2023-11-21 Micron Technology, Inc. Methods of forming microelectronic devices and memory devices
US11751408B2 (en) 2021-02-02 2023-09-05 Micron Technology, Inc. Methods of forming microelectronic devices, and related microelectronic devices, memory devices, and electronic systems

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4989059A (en) * 1988-05-13 1991-01-29 Mobil Solar Energy Corporation Solar cell with trench through pn junction
JPWO2006087786A1 (en) * 2005-02-17 2008-07-03 三菱電機株式会社 Manufacturing method of solar cell
KR20090091562A (en) * 2008-02-25 2009-08-28 엘지전자 주식회사 Colar cell and mehtod for manufacturing the same
TWI398958B (en) * 2010-01-08 2013-06-11 Tainergy Tech Co Ltd Solar cell and method for manufacturing the same
JP2011151192A (en) * 2010-01-21 2011-08-04 Sharp Corp Solar cell, solar cell with interconnector, and manufacturing method thereof
JP5436276B2 (en) * 2010-03-11 2014-03-05 三菱電機株式会社 Manufacturing method of solar cell
US8071418B2 (en) * 2010-06-03 2011-12-06 Suniva, Inc. Selective emitter solar cells formed by a hybrid diffusion and ion implantation process
WO2012008061A1 (en) * 2010-07-16 2012-01-19 シラクセル株式会社 Silicon solar cell having boron diffusion layer and method for manufacturing same
CN102332488A (en) * 2011-05-25 2012-01-25 湖南红太阳光电科技有限公司 Method and apparatus for laser edge isolation of crystalline silicon solar cells

Also Published As

Publication number Publication date
WO2014188773A1 (en) 2014-11-27
TW201511319A (en) 2015-03-16
TWI624078B (en) 2018-05-11
JPWO2014188773A1 (en) 2017-02-23

Similar Documents

Publication Publication Date Title
JP6299757B2 (en) Manufacturing method of solar cell
US20110000532A1 (en) Solar Cell Device and Method of Manufacturing Solar Cell Device
KR102120147B1 (en) Solar cell and method of manufacturing the same
JP6410951B2 (en) Solar cell and method for manufacturing solar cell
US20170236964A1 (en) Solar cell module
JP2011155041A (en) Solar cell element and solar cell module
JP2010010493A (en) Solar cell and method of manufacturing the same
JP6021392B2 (en) Method for manufacturing photoelectric conversion device
JP2016139762A (en) Method of manufacturing solar cell element
JP2014239085A (en) Solar battery element and method of manufacturing the same
JP2011146678A (en) Method of manufacturing solar cell device
JP2010177444A (en) Solar cell element and method for manufacturing solar cell element
TWI415272B (en) Method of fabricating rear surface point contact of solar cells
JP2012209316A (en) Solar cell element and solar cell module
US11222991B2 (en) Solar cell and method for manufacturing the same
WO2017018300A1 (en) Solar cell and method for manufacturing solar cell
US11038078B2 (en) Method for manufacturing high efficiency solar cell
US10700223B2 (en) High photoelectric conversion efficiency solar battery cell and method for manufacturing high photoelectric conversion solar battery cell
JP2014086587A (en) Method for manufacturing solar cell and solar cell
TWI668880B (en) Solar battery unit and solar battery module
TW201817021A (en) Solar cell with high photoelectric conversion efficiency and method for manufacturing solar cell with high photoelectric conversion efficiency
TWI713230B (en) Solar cell and its manufacturing method
KR20050098473A (en) Solar cell and fabrication method thereof
JP2012138553A (en) Solar cell element and manufacturing method of the same
JP6313086B2 (en) Crystalline silicon solar cell and method for manufacturing the same, method for manufacturing solar cell module, method for manufacturing concentrating solar cell module

Legal Events

Date Code Title Description
A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20170207

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20170316

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20170905

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20171122

A911 Transfer of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20171129

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20180130

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20180212

R150 Certificate of patent or registration of utility model

Ref document number: 6299757

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150