JPH0387388A - Electrode for plasma etching - Google Patents
Electrode for plasma etchingInfo
- Publication number
- JPH0387388A JPH0387388A JP22229089A JP22229089A JPH0387388A JP H0387388 A JPH0387388 A JP H0387388A JP 22229089 A JP22229089 A JP 22229089A JP 22229089 A JP22229089 A JP 22229089A JP H0387388 A JPH0387388 A JP H0387388A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- plasma etching
- holes
- carbon material
- small
- 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.)
- Pending
Links
- 238000001020 plasma etching Methods 0.000 title claims abstract description 17
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 19
- 239000002931 mesocarbon microbead Substances 0.000 claims abstract description 10
- 238000005530 etching Methods 0.000 abstract description 9
- 239000011230 binding agent Substances 0.000 abstract description 3
- 229910052736 halogen Inorganic materials 0.000 abstract description 3
- 150000002367 halogens Chemical class 0.000 abstract description 3
- 238000000746 purification Methods 0.000 abstract description 3
- 239000002994 raw material Substances 0.000 abstract description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 239000007789 gas Substances 0.000 description 6
- 229910002804 graphite Inorganic materials 0.000 description 5
- 239000010439 graphite Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- KYKAJFCTULSVSH-UHFFFAOYSA-N chloro(fluoro)methane Chemical compound F[C]Cl KYKAJFCTULSVSH-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011294 coal tar pitch Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 239000011285 coke tar Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 239000011271 tar pitch Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は半導体集積回路を製造するに際し、ウェハのプ
ラズマエツチング加工に用いる電極に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrode used in plasma etching of a wafer in manufacturing semiconductor integrated circuits.
従来技術及びその課題
半導体集積回路の微細化と高密度化技術の発展とともに
、高精度で微細パターンを形成できる平行平板形電極を
使用するプラズマエツチング技術の重要性が高まってい
る。BACKGROUND OF THE INVENTION With the development of miniaturization and high-density technology for semiconductor integrated circuits, the importance of plasma etching technology using parallel plate electrodes that can form fine patterns with high accuracy is increasing.
平行平板形の電極を使用するプラズマエツチングは、上
下に対向する一組の平滑板状の電極間に高周波電力を印
加して発生させたガスプラズマによってウェハをエツチ
ングする方法であり、該プラズマ中に存在するハロゲン
系反応ガスのフリーラジカルとイオンが電極内の電界に
引かれて下部電極上に置かれたウェハに垂直に入射し、
フォトレジストのない部分を食刻していくプロセス機構
からなっている。Plasma etching using parallel plate-shaped electrodes is a method of etching a wafer with gas plasma generated by applying high-frequency power between a pair of vertically facing smooth plate-shaped electrodes. Free radicals and ions of the halogen-based reaction gas present are drawn by the electric field within the electrode and are incident perpendicularly onto the wafer placed on the lower electrode.
It consists of a process mechanism that etches the areas where there is no photoresist.
このプラズマエツチングに用いられる電極には、導電性
、化学的安定性等の特性が必要とされ、しかも高純度の
ものが要求されている。従来、プラズマエツチング用電
極としては、主に金属質の円板が用いられていたが、金
属質の電極は、化学的安定性が不十分であるうえに高純
度にすることが困難であるという問題点があった。The electrodes used in this plasma etching are required to have properties such as conductivity and chemical stability, and are also required to be highly pure. Conventionally, metallic disks have been mainly used as electrodes for plasma etching, but metallic electrodes have insufficient chemical stability and are difficult to obtain with high purity. There was a problem.
そこで、これに代わる電極材として黒鉛が試みられてい
る。黒鉛は優れた導電性と化学的安定性を備え、高純度
化も容易であることから特性的には極めて好適な電極材
料である。しかしながら、この材料は、コークスあるい
はカーボンの粉砕物をタールピッチ等のバインダー成分
と共に混合再粉砕した後に底形、焼成、黒鉛化すること
により製造されており、２戊分系であるため、密度が高
め難く、緻密かつ均質な組織を得ることが困難である。Therefore, attempts have been made to use graphite as an electrode material to replace this. Graphite has excellent conductivity and chemical stability, and can be easily purified, making it an extremely suitable electrode material. However, this material is manufactured by mixing crushed coke or carbon with a binder component such as tar pitch, re-pulverizing it, sintering it, and graphitizing it, and since it is a two-part system, its density is low. It is difficult to increase the thickness and obtain a dense and homogeneous structure.
このため、ガスの透過性が不均質となったり、組織を構
成する粒体が脱落して、消耗を早めたり、更にウェハの
上面を汚損して所定パターンの形成を阻害する等の欠点
を招く恐れがある。This results in disadvantages such as non-uniform gas permeability, particles that make up the structure falling off, accelerating wear, and further contaminating the top surface of the wafer and inhibiting the formation of a predetermined pattern. There is a fear.
課題を解決するための手段
本発明は、エツチング加工を高精度かつ高速度で行い得
、しかも耐久性に優れたプラズマエツチング用電極を提
供することを目的とする。Means for Solving the Problems It is an object of the present invention to provide a plasma etching electrode that can perform etching with high precision and high speed and has excellent durability.
すなわち、本発明は、メソカーボンマイクロビーズを原
料とする高純度化等方性高密度炭素材からなり、該炭素
材に多数の貫通小孔を設けてなることを特徴とするプラ
ズマエツチング用電極に係るものである。That is, the present invention provides an electrode for plasma etching, which is made of a highly purified isotropic high-density carbon material made from mesocarbon microbeads, and is characterized in that the carbon material is provided with a large number of through holes. This is related.
本発明者の研究によれば、メソカーボンマイクロビーズ
を原料として得られる高純度の炭素材は均質な組織を有
しており、該炭素材を電極に用いたとき、プラズマエツ
チング用電極としての要求特性ならびに実用性能を十分
に満足し得ることが見出された。また、この炭素材に多
数の貫通小孔を設けることにより、−層エッチング速度
が上がることを見出した。本発明は、これら知見に基づ
いて完成されたものである。According to the research of the present inventor, a high-purity carbon material obtained using mesocarbon microbeads as a raw material has a homogeneous structure, and when this carbon material is used for an electrode, it meets the requirements for an electrode for plasma etching. It has been found that the properties and practical performance can be fully satisfied. It has also been found that by providing a large number of small through holes in this carbon material, the -layer etching rate can be increased. The present invention was completed based on these findings.
本発明にいうメソカーボンマイクロビーズは、黒鉛類似
の構造を有する球形の炭素材であリラメラ構造を持つ物
質である。この球形粒子をランダムに配列させることに
よって、均質で、かつ異方比の極めて小さい組織構造を
有する炭素材になる。The mesocarbon microbeads referred to in the present invention are spherical carbon materials having a structure similar to graphite, and are substances having a relamellar structure. By randomly arranging these spherical particles, a carbon material having a homogeneous structure with an extremely small anisotropy ratio can be obtained.
またメソカーボンマイクロビーズは、粒径も非常に良く
そろっているため、得られる炭素材は緻密であるととも
に、微細気孔を有し、その気孔径分布も非常にシャープ
なものとなる。Furthermore, since the mesocarbon microbeads have very uniform particle sizes, the obtained carbon material is dense and has fine pores, and the pore size distribution is also very sharp.
本発明電極の製造は、電極を製造するに際し用いられる
公知方法に比べて簡素化することができる。例えばメソ
カーボンマイクロビーズを、バインダーレスで底形、焼
成し、さらに必要であれば黒鉛化する。上記のようにし
て、かき密度１．９０ｇ／ｃｍ３程度以上、曲げ強度９
００ｋｇｆ／ｃｍ２程度以上の高密度且つ高強度の等方
性炭素材を得る。この炭素材に反応ガスをプラズマ中に
、より円滑に流入させるための貫通小孔を設ける。貫通
小孔の孔径は、広い範囲から適宜選択されるが、通常直
径０． １〜１．０ｍｍ程度、好ましくは０．４〜０．
６ｍｍとするのがよい。また、貫通小孔の開孔率（開
孔前の炭素材表面積に対する開孔後の空洞面積を百分率
で表したもの）も広範囲から適宜選択されるが、通常０
．５〜２０％、好ましくは１〜３％とするのがよい。貫
通小孔を炭素材に設ける方法としては、上記孔径及び開
孔率範囲の孔を開ける精度のあるものであれば特に制限
されず、例えば超硬のドリル、レーザー等を用いて行え
ばよい。次に、この多数の貫通小孔が設けられた炭素材
をハロゲン、フロン等の精製ガスによって高温下で高純
度化処理し、さらに洗浄を行なえばよい。上記高純度化
により、炭素材は、灰分（不純物）の量が約１００ ｐ
ｐｍから５ ｐｐｍ程度以下までとなり、プラズマエツ
チング用電極に適したものとなる。The production of electrodes according to the invention can be simplified compared to known methods used to produce electrodes. For example, mesocarbon microbeads are shaped without a binder, fired, and further graphitized if necessary. As above, the scraping density is about 1.90 g/cm3 or more, and the bending strength is 9.
A high-density and high-strength isotropic carbon material of approximately 00 kgf/cm2 or more is obtained. A small through hole is provided in this carbon material to allow the reactive gas to flow more smoothly into the plasma. The diameter of the through hole is appropriately selected from a wide range, but is usually 0. Approximately 1 to 1.0 mm, preferably 0.4 to 0.0 mm.
It is better to set it to 6 mm. In addition, the porosity of the through-holes (expressed as a percentage of the cavity area after opening to the surface area of the carbon material before opening) is appropriately selected from a wide range, but is usually 0.
．． The content is preferably 5 to 20%, preferably 1 to 3%. The method for providing small through-holes in the carbon material is not particularly limited as long as it has the accuracy to drill holes within the above-mentioned hole diameter and porosity range, and may be performed using, for example, a carbide drill, a laser, or the like. Next, the carbon material provided with the large number of through holes is purified at high temperature using a purified gas such as halogen or chlorofluorocarbon, and then washed. Due to the above-mentioned high purification, the amount of ash (impurity) in the carbon material is approximately 100 p.
pm to about 5 ppm or less, making it suitable for plasma etching electrodes.
上記のようにして製造されるプラズマエツチング用電極
は、均質な組織を有しており、高純度、高精度、高化学
的安定性等の適合物性を具備しているものである。The plasma etching electrode manufactured as described above has a homogeneous structure and has suitable physical properties such as high purity, high precision, and high chemical stability.
発明の効果
本発明のプラズマエツチング用電極は、均質な組織構造
並びに物性が総合的に作用して、使用時の組織崩壊およ
び過度の消耗を極めて効果的に抑制する。Effects of the Invention In the plasma etching electrode of the present invention, the homogeneous structure and physical properties work together to extremely effectively suppress tissue collapse and excessive wear during use.
また、本発明電極は、−元系原料よりなる緻密且つ均質
な組織構造であるため、プラズマ中への反応ガスの流入
が円滑かつ均一となり、エツチング速度をより一層速め
るとともに、エツチングパターンを高精度に形成するた
めに有効に機能する。In addition, since the electrode of the present invention has a dense and homogeneous structure made of - elemental raw materials, the inflow of the reactive gas into the plasma is smooth and uniform, which further increases the etching rate and allows the etching pattern to be formed with high precision. It functions effectively to form.
実施例
以下、実施例により本発明の特徴とするところを一層明
確にする。EXAMPLES The features of the present invention will be further clarified through examples below.
実施例１
平均粒径１５μｍのメソカーボンマイクロビーズをゴム
モールド内に充填し、１０００ ｋｇｆ／ｃｍ２の圧力
で静水圧成形機にて成形した後、不活性雰囲気中１００
０℃で焼成し、さらに２５００°Ｃで黒鉛化して等方性
炭素ブロックを作製した。このブロックを所定の電極形
状に加工し、マシニングセンターにより直径０．５■の
貫通小孔を開孔率２％で設けた後に、高純度化処理及び
洗浄を行った。得られた電極の特性を第１表に示す。Example 1 Mesocarbon microbeads with an average particle size of 15 μm were filled into a rubber mold, molded using an isostatic press at a pressure of 1000 kgf/cm2, and then molded at 100 kgf/cm2 in an inert atmosphere.
It was fired at 0°C and further graphitized at 2500°C to produce an isotropic carbon block. This block was processed into a predetermined electrode shape, small through holes with a diameter of 0.5 square meters were formed using a machining center at an opening rate of 2%, and then high purification treatment and cleaning were performed. The properties of the obtained electrode are shown in Table 1.
この電極をプラズマエツチング装置にセットし、従来か
ら使用されているコークスとコールタールピッチの２戊
分系からなる黒鉛電極との性能の比較テストを行った。This electrode was set in a plasma etching device, and a performance comparison test was conducted with a conventionally used graphite electrode made of a two-part system of coke and coal tar pitch.
結果を従来品を１００とした場合の相対値として第２表
に示す。その結果、電極板は長時間の使用によっても組
織の崩落現象は全く認められず、放電異物の数も極端に
減少している。また、消耗の度合も、従来黒鉛電極の１
／２程度であり、ガスの流入も円滑で非常に均一である
ため得られたエツチングパターンも高精度のものであっ
た。The results are shown in Table 2 as relative values when the conventional product is set as 100. As a result, no tissue collapse phenomenon was observed in the electrode plate even after long-term use, and the number of discharge foreign particles was extremely reduced. In addition, the degree of wear and tear is about 10% lower than that of conventional graphite electrodes.
/2, and the gas flow was smooth and very uniform, so the etching pattern obtained was also highly accurate.
以上のように、本発明の電極は、一般カーボン材の電極
の使用時に起こる粒体脱落などの組織崩壊および過度の
消耗現象を効果的に抑制することが出来るために、長期
間にわたり安定した高精度の加工が保証され、またエツ
チング速度を一段と速め得るプラズマエツチング用電極
として優れていることは明らかである。As described above, the electrode of the present invention can effectively suppress structural collapse such as particle shedding and excessive wear phenomena that occur when electrodes made of general carbon materials are used. It is clear that this electrode is excellent as a plasma etching electrode that guarantees precision processing and can further increase the etching speed.
（以 上）(that's all)
Claims (1)
度化等方性高密度炭素材からなり、該炭素材に多数の貫
通小孔を設けてなることを特徴とするプラズマエッチン
グ用電極。(1) An electrode for plasma etching, characterized in that it is made of a highly purified isotropic high-density carbon material made from mesocarbon microbeads, and the carbon material is provided with a large number of small through holes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22229089A JPH0387388A (en) | 1989-08-29 | 1989-08-29 | Electrode for plasma etching |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22229089A JPH0387388A (en) | 1989-08-29 | 1989-08-29 | Electrode for plasma etching |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0387388A true JPH0387388A (en) | 1991-04-12 |
Family
ID=16780051
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22229089A Pending JPH0387388A (en) | 1989-08-29 | 1989-08-29 | Electrode for plasma etching |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0387388A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07278851A (en) * | 1994-09-19 | 1995-10-24 | Tokai Carbon Co Ltd | Electrode plate for plasma etching and its production |
-
1989
- 1989-08-29 JP JP22229089A patent/JPH0387388A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07278851A (en) * | 1994-09-19 | 1995-10-24 | Tokai Carbon Co Ltd | Electrode plate for plasma etching and its production |
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