JPH0441490B2 - - Google Patents
Info
- Publication number
- JPH0441490B2 JPH0441490B2 JP11380383A JP11380383A JPH0441490B2 JP H0441490 B2 JPH0441490 B2 JP H0441490B2 JP 11380383 A JP11380383 A JP 11380383A JP 11380383 A JP11380383 A JP 11380383A JP H0441490 B2 JPH0441490 B2 JP H0441490B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- film
- semiconductor
- reflectance
- thickness
- 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.)
- Expired
Links
- 238000010438 heat treatment Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 10
- 230000001678 irradiating effect Effects 0.000 claims description 2
- 239000010408 film Substances 0.000 description 41
- 239000004065 semiconductor Substances 0.000 description 21
- 230000001681 protective effect Effects 0.000 description 14
- 229910004298 SiO 2 Inorganic materials 0.000 description 9
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 229910052786 argon Inorganic materials 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- High Energy & Nuclear Physics (AREA)
- Toxicology (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Recrystallisation Techniques (AREA)
Description
本発明は半導体の加熱方法、特にレーザなどの
光源で、主な放射エネルギーの波長が近接し、か
つその強度がほぼ同じ２つの光源を用いて物体を
加熱する方法に関する。
光を用いた物体の加熱方法は、半導体のイオン
注入層の不純物イオンの活性化などに用いられて
いる。半導体結晶を高温に加熱する場合には表面
の汚染防止、加熱された半導体の飛散防止や形状
変化の防止のため表面に保護膜を付けることが行
なわれる。この膜は光を使う加熱法であることか
ら当然透明である必要があるが、その場合保護膜
と空気、保護膜と半導体との両界面による反射光
の干渉のため入射強度が膜厚に依存して大きく変
化するという問題がある。
一方、LSIなどへの応用を考えると、半導体結
晶は直径数センチの円板状ウエハを用いるが、こ
のような広い面積に均一な厚さの膜を形成するこ
とはむずかしい。現状では膜厚を光源の発振波長
よりずつと薄くして膜厚の変化の影響を少くする
方法がとられている。しかし、加熱半導体の形状
変化の防止のためにはある程度の機械的強度が必
要で、従来法で用いられる薄い膜では形状変化を
起したり、また任意の厚さの膜では膜厚の分散に
より半導体への光の入射強度が場所によつて大き
く変化してしまう。通常、半導体プロセスで用い
る光加熱法の場合、試料の温度のわずかな変化
が、結果を大きく変化させてしまうため、このよ
うな入射強度のばらつきは光加熱法の再現性、均
一性をそこない、実用化の大きな妨げとなつてい
る。
本発明は上記従来の欠点を解消するもので、主
な放射エネルギーが２つの近接した発光波長λ1，
λ2であり、かつ、その放射エネルギー強度がほぼ
等しい光源を用いて物体を加熱する方法におい
て、その物体の表面を屈折率ｎで、厚さｄが
λ1λ2／2n｜λ1−λ2｜（Ｋ＋0.4）〜λ1λ2／2n｜λ1
−λ2｜（Ｋ
＋0.6）（但しＫはゼロ以上の整数）の範囲内の膜
で覆い、その上方より光を、照射することを特徴
とするものである。
以下に本発明の実施例を図面により説明する。
第１図は半導体表面に透明保護膜をつけた場合
の断面図である。１は半導体、２は透明保護膜、
３は空気、４は半導体１と透明保護膜２との界
面、５は２透明保護膜と空気３との界面、６は入
射光である。半導体１、透明保護膜２、空気３の
屈折率をそれぞれn1，n2，n3、透明保護膜２の厚
さをt2、入射光６の波長をλとし、r1，r2，δを、
r1＝（n2−n1）／（n2＋n1） (1)
r2＝（n3−n2）／（n2＋n2） (2)
δ＝2πn2t2／λ (3)
とすると、反射率Ｒは次式で表わされる。
Ｒ＝｜r2＋r1exp（−2iδ）／１＋r2．r1exp（−2iδ）
2｜(4)
第２図は、λとしてアルゴンレーザの最高強度
をもつ波長0.5145μmの半導体１として屈折率4.21
のシリコン、保護膜２として屈折率1.46のSiO2と
したときの膜厚ｄの変化による反射率の変化を示
す。第２図によつて膜厚により反射率が大きく変
化していることが判る。
第３図は光源の波長としてアルゴンレーザの主
要な発振波長である0.5145μm，0.488μmの光を用
い、他の条件は第２図の場合と同一とした場合の
二つの波長の光を合成した反射率を示す。この場
合には膜厚1.6μm付近で膜厚により反射率の変化
のない部分がなることが判る。これは２つの波長
の光の位相が、入射後第１図の界面５に戻つてき
たときに丁度半波度ずれていて、一方の波長の光
が反射強度を強めあうときには、他の波長の光は
反射強度を弱めあい、結果的に合成した反射強度
が一定となるためである。２つの光の波長をλ1，
λ2，m1，m2を整数、膜厚をｄ、屈折率をｎとす
るとこの条件は次の２つの式によつて表わされ
る。
2dn＝m1λ1 (5)
2dn＝（m2＋１／２）λ2 (6)
この両式から
ｄ＝λ1λ2／2n（λ1−λ2）m2−m1＋１／２） (7)
となる。ｄは正であることからＫをゼロ以上の整
数とし、
ｄ＝λ1λ2／2n｜λ1−λ2｜（Ｋ＋１／２） (8)
と表わされる。ｄの値はλ1λ2／2n｜λ1λ2｜の周
期で変化するが、その周期の10％程度のずれでも
反射率の変化は変化の最大幅の1/3であるので膜
厚としてはｄ±0.1λ1λ2／2n｜λ1−λ2｜の範囲に
あれれば反射率は安定しているといえる。
実際、半導体の光加熱によく使われるアルゴン
レーザは表１に示すような発光スペクトルをもつ
ている。
The present invention relates to a method of heating a semiconductor, and more particularly to a method of heating an object using two light sources such as lasers whose main radiant energy wavelengths are close to each other and whose intensity is approximately the same. A method of heating an object using light is used, for example, to activate impurity ions in an ion-implanted layer of a semiconductor. When a semiconductor crystal is heated to a high temperature, a protective film is applied to the surface to prevent surface contamination, scattering of the heated semiconductor, and shape change. Since this film is heated using light, it naturally needs to be transparent, but in this case, the incident intensity depends on the film thickness due to the interference of reflected light from the interfaces between the protective film and the air, and between the protective film and the semiconductor. The problem is that it changes greatly. On the other hand, when considering applications such as LSI, disk-shaped wafers with a diameter of several centimeters are used for semiconductor crystals, but it is difficult to form a film of uniform thickness over such a large area. Currently, the method used is to reduce the effect of changes in film thickness by making the film thickness smaller than the oscillation wavelength of the light source. However, a certain degree of mechanical strength is required to prevent the heated semiconductor from changing its shape, and thin films used in conventional methods may change their shape, and films of arbitrary thickness may suffer from dispersion of the film thickness. The intensity of light incident on a semiconductor varies greatly depending on the location. Normally, in the case of the optical heating method used in semiconductor processes, a slight change in the temperature of the sample can greatly change the results, so such variations in incident intensity impair the reproducibility and uniformity of the optical heating method. , which is a major hindrance to practical application. The present invention solves the above-mentioned conventional drawbacks, and the main radiation energy is emitted from two adjacent emission wavelengths λ 1 ,
In a method of heating an object using a light source whose radiant energy intensity is approximately the same, the surface of the object has a refractive index n and a thickness d of λ 1 λ 2 / 2n | 2 | (K + 0.4) ~ λ 1 λ 2 /2n | λ 1
-λ 2 |(K +0.6) (where K is an integer greater than or equal to zero), and is characterized by being covered with a film and irradiating light from above. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view when a transparent protective film is attached to the semiconductor surface. 1 is a semiconductor, 2 is a transparent protective film,
3 is air, 4 is an interface between semiconductor 1 and transparent protective film 2, 5 is an interface between 2 transparent protective films and air 3, and 6 is incident light. The refractive indices of the semiconductor 1, the transparent protective film 2, and the air 3 are n 1 , n 2 , n 3 , the thickness of the transparent protective film 2 is t 2 , the wavelength of the incident light 6 is λ, and r 1 , r 2 , δ, r 1 = (n 2 − n 1 ) / (n 2 + n 1 ) (1) r 2 = (n 3 − n 2 ) / (n 2 + n 2 ) (2) δ = 2πn 2 t 2 / When λ (3) is assumed, the reflectance R is expressed by the following equation. R=| r2 + r1exp (-2iδ)/1+ r2 . r 1 exp (−2iδ)
2 | (4) Figure 2 shows a semiconductor 1 with a refractive index of 4.21 and a wavelength of 0.5145 μm, which has the highest intensity of the argon laser as λ.
The graph shows the change in reflectance due to change in film thickness d when SiO 2 with a refractive index of 1.46 is used as the protective film 2. It can be seen from FIG. 2 that the reflectance changes greatly depending on the film thickness. Figure 3 shows the synthesis of light of two wavelengths using the light source wavelengths of 0.5145μm and 0.488μm, which are the main oscillation wavelengths of an argon laser, and keeping the other conditions the same as in Figure 2. Indicates reflectance. In this case, it can be seen that there is a part where the reflectance does not change depending on the film thickness around 1.6 μm. This is because the phases of the two wavelengths of light are exactly half a wave apart when they return to the interface 5 in Figure 1 after being incident, and when the light of one wavelength strengthens the reflected intensity, the phase of the light of the other wavelength is shifted. This is because the reflected intensity of the light weakens each other, and as a result, the combined reflected intensity becomes constant. Let the wavelengths of the two lights be λ 1 ,
When λ 2 , m 1 , and m 2 are integers, the film thickness is d, and the refractive index is n, this condition is expressed by the following two equations. 2dn=m 1 λ 1 (5) 2dn=(m 2 +1/2) λ 2 (6) From both equations, d=λ 1 λ 2 /2n (λ 1 −λ 2 )m 2 −m 1 +1/2 ) (7) becomes. Since d is positive, K is an integer greater than or equal to zero, and is expressed as d=λ 1 λ 2 /2n | λ 1 −λ 2 | (K+1/2) (8). The value of d changes with a period of λ 1 λ 2 /2n | λ 1 λ 2 |, but even if the period shifts by about 10%, the change in reflectance is 1/3 of the maximum width of the change, so the film thickness It can be said that the reflectance is stable if it is within the range of d±0.1λ 1 λ 2 /2n | λ 1 −λ 2 |. In fact, argon lasers, which are often used for optical heating of semiconductors, have emission spectra as shown in Table 1.
【表】
主要な発光は波長0.5145μm、と0.488μmの光で
ある。この光を用いてシリコン表面のSiO2の膜
厚を変化させた場合の反射率の変化を第４図に示
す。７は反射率、８，９で示した区間が本発明に
よる膜厚で、この場合は８はは1.30μmから
1.95μm、９は4.54μmから5.19μmである。アルゴ
ンレーザの場合には主要２波長以外にも多くの発
光波長をもつため、一様な周期性をもたないが、
他の膜厚に較べ本発明で規制した膜厚が、膜厚変
化に対し反射率が安定していることは明らかであ
る。また、上記のような膜厚は通常のCVD法や
スパツタ法による膜成長で容易に制御しうる膜厚
である。
以上説明では加熱物体として半導体シリコン、
保護膜としてSiO2を用いてきたが、説明から明
らかなように他の半導体や、半導体以外の物体に
対する加熱においても、また他の種類の透明保護
膜であつても均一な入射パワーが必要とされる場
合には、本発明は適用可能であることは明らかで
ある。
以上のように本発明によれば、物体（半導体な
ど）の表面を被覆する透明膜の膜厚の範囲を規制
することによつて膜厚の変化に対し、安定な入射
光線強度を維持でき、光加熱の均一性を確保でき
る効果を有するものである。[Table] The main light emission is light with wavelengths of 0.5145μm and 0.488μm. FIG. 4 shows the change in reflectance when the thickness of SiO 2 on the silicon surface is changed using this light. 7 is the reflectance, and the section 8 and 9 is the film thickness according to the present invention, in this case 8 is from 1.30 μm.
1.95 μm, 9 is 4.54 μm to 5.19 μm. In the case of an argon laser, it has many emission wavelengths in addition to the two main wavelengths, so it does not have uniform periodicity.
It is clear that the film thickness regulated by the present invention has a more stable reflectance with respect to changes in film thickness than other film thicknesses. Furthermore, the film thickness as described above can be easily controlled by film growth using a normal CVD method or sputtering method. In the above explanation, semiconductor silicon is used as the heated object.
Although SiO 2 has been used as a protective film, as is clear from the explanation, uniform incident power is required for heating other semiconductors and objects other than semiconductors, and even for other types of transparent protective films. It is clear that the present invention is applicable in such cases. As described above, according to the present invention, by regulating the range of thickness of a transparent film that covers the surface of an object (such as a semiconductor), stable incident light intensity can be maintained despite changes in film thickness. This has the effect of ensuring uniformity of optical heating.
第１図は半導体を光を用いて加熱する場合の試
料の断面模式図、第２図は波長0.5145μmの光に
対し、シリコン表面にSiO2膜をつけた場合の反
射率のSiO2膜依存性を示す図、第３図は波長
0.5145μmと0.488μmの２つの同一強度の光に対
し、シリコン表面にSiO2膜をつけた場合の反射
率のSiO2膜厚依存性を示す図、第４図はアルゴ
ンレーザの光に対し、シリコン表面にSiO2膜を
つけた場合の反射率のSiO2膜厚依存性を示す図
である。
１……半導体、２……透明保護膜、３……空
気、４，５……界面、６……入射光、７……反射
率、８，９……本発明による表面保護膜の範囲。
Figure 1 is a schematic cross-sectional view of a sample when a semiconductor is heated with light, and Figure 2 shows the dependence of reflectance on the SiO 2 film when a SiO 2 film is attached to the silicon surface for light with a wavelength of 0.5145 μm. Figure 3 shows the wavelength.
Figure 4 shows the dependence of the reflectance on the SiO 2 film thickness when a SiO 2 film is attached to the silicon surface for two lights of the same intensity of 0.5145 μm and 0.488 μm. FIG. 3 is a diagram showing the dependence of reflectance on SiO 2 film thickness when a SiO 2 film is attached to a silicon surface. 1... Semiconductor, 2... Transparent protective film, 3... Air, 4, 5... Interface, 6... Incident light, 7... Reflectance, 8, 9... Range of surface protective film according to the present invention.
Claims (1)
長λ1，λ2であり、かつその放射エネルギー強度が
ほぼ等しい光源を用いて物体を加熱する方法にお
いて、その物体の表面を屈折率ｎで、厚さｄが λ1λ2／2n｜λ1−λ2｜（Ｋ＋0.4）〜λ1λ2／2n｜λ1
−λ2｜（Ｋ ＋0.6）（但しＫはゼロ以上の整数）の範囲の透明
膜で覆い、その上方より光を照射することを特徴
とする光加熱方法。[Claims] 1. A method for heating an object using a light source whose main radiant energy is at two adjacent emission wavelengths λ 1 and λ 2 and whose radiant energy intensities are approximately equal. When the refractive index is n and the thickness d is λ 1 λ 2 /2n | λ 1 −λ 2 | (K+0.4) ~ λ 1 λ 2 /2n | λ 1
-λ 2 |(K +0.6) (where K is an integer greater than or equal to zero) A light heating method characterized by covering the film with a transparent film in the range of -λ 2 |(K +0.6) (where K is an integer greater than or equal to zero) and irradiating light from above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11380383A JPS607124A (en) | 1983-06-24 | 1983-06-24 | Photo heating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11380383A JPS607124A (en) | 1983-06-24 | 1983-06-24 | Photo heating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS607124A JPS607124A (en) | 1985-01-14 |
| JPH0441490B2 true JPH0441490B2 (en) | 1992-07-08 |
Family
ID=14621458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11380383A Granted JPS607124A (en) | 1983-06-24 | 1983-06-24 | Photo heating method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS607124A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4769491B2 (en) * | 2004-06-04 | 2011-09-07 | 株式会社 液晶先端技術開発センター | Crystallization method, thin film transistor manufacturing method, thin film transistor, and display device |
| TW200541079A (en) | 2004-06-04 | 2005-12-16 | Adv Lcd Tech Dev Ct Co Ltd | Crystallizing method, thin-film transistor manufacturing method, thin-film transistor, and display device |
| JP4939673B2 (en) * | 2005-05-11 | 2012-05-30 | 日本電産テクノモータホールディングス株式会社 | Trigger switch and motor drive circuit using the same |
| JP2007021620A (en) * | 2005-07-13 | 2007-02-01 | Nidec Shibaura Corp | Power tool |
| JP4404057B2 (en) | 2006-02-10 | 2010-01-27 | ソニー株式会社 | Non-contact switch and recording medium and operation member using the same |
-
1983
- 1983-06-24 JP JP11380383A patent/JPS607124A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS607124A (en) | 1985-01-14 |
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