JPS6214033B2 - - Google Patents
Info
- Publication number
- JPS6214033B2 JPS6214033B2 JP56113958A JP11395881A JPS6214033B2 JP S6214033 B2 JPS6214033 B2 JP S6214033B2 JP 56113958 A JP56113958 A JP 56113958A JP 11395881 A JP11395881 A JP 11395881A JP S6214033 B2 JPS6214033 B2 JP S6214033B2
- Authority
- JP
- Japan
- Prior art keywords
- etching
- gold
- acid
- alloy film
- acetic acid
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/16—Acidic compositions
- C23F1/30—Acidic compositions for etching other metallic material
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
- Weting (AREA)
Description
【発明の詳細な説明】
本発明は半導体ウエーハ等の基板上に形成され
た金、または金合金膜のエツチングに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to etching of gold or gold alloy films formed on substrates such as semiconductor wafers.
金（Au），金合金は古くから半導体電極材料と
して使用されている。特に最近、―族化合物
半導体を用いた発光ダイオード、レーザが実用化
されるに伴い、金（Au）あるいは金―ゲルマニ
ウム（Au／Ge）、金―シリコン（Au／Si）、金―
ベリリウム（Au／Be）、金―亜鉛（Au／Zn）等
の金合金は―Ｖ族に対して良好なオーミツク接
触を示す材料として現在広く用いられている。こ
れらAuを主材料とした膜を選択的にエツチする
ためには、通常レジスト膜をマスクとして、ヨウ
素ヨウ化カリ、水からなるヨードエツチ液が採用
されている。このヨードエツチ液はAuまたはAu
合金に対してエツチング速度が早いという特徴が
あるが、他方では―族、―族化合物半導
体とも反応する。このためヨードエツチ液による
処理を施した半導体ウエーハには無数のエツチピ
ツトが発生する。従つて、このヨードエツチ液を
使用する場合は、十分な注意が必要となり、例え
ば選択エツチ完了後、直ちにエツチ液から半導体
ウエーハを取り出さぬば表面は粗面となる。この
ことは一方ではエツチ不足等のトラブルを発生さ
せ、工程管理上大きな問題となる。そのため、半
導体ウエーハ表面を完全に鏡面に保つ必要がある
場合はヨードエツチ液は使用出来ず、一般にはリ
フトオフ法が採用されている。しかし、リフトオ
フ法では電極材料の膜厚が0.5μ以上になると電
極材料を選択的にリフトオフすることが非常に困
難となる。 Gold (Au) and gold alloys have been used as semiconductor electrode materials for a long time. Especially recently, with the practical use of light-emitting diodes and lasers using - group compound semiconductors, gold (Au), gold-germanium (Au/Ge), gold-silicon (Au/Si), gold-
Gold alloys such as beryllium (Au/Be) and gold-zinc (Au/Zn) are currently widely used as materials that exhibit good ohmic contact with the -V group. In order to selectively etch these Au-based films, an iodine etch solution consisting of iodine, potassium iodide, and water is usually used using a resist film as a mask. This iodine etchant is Au or Au
It has the characteristic of having a fast etching rate with respect to alloys, but on the other hand, it also reacts with - group and - group compound semiconductors. For this reason, countless etch pits are generated on a semiconductor wafer that has been treated with an iodine etchant. Therefore, when using this iodine etchant, great care must be taken; for example, if the semiconductor wafer is not removed from the etchant immediately after selective etching is completed, the surface will be rough. On the one hand, this causes problems such as insufficient etching, which poses a major problem in process control. Therefore, if it is necessary to keep the surface of a semiconductor wafer completely mirror-like, iodine etchant cannot be used, and the lift-off method is generally used. However, in the lift-off method, when the film thickness of the electrode material exceeds 0.5 μm, it becomes extremely difficult to selectively lift off the electrode material.
本発明はこれらの問題点を解決するものであ
り、半導体ウエーハ等の基板表面に荒れを与える
ことなく、この上に形成された任意の厚さのAu
またはAu合金膜を選択的にエツチングする方法
を提供するものである。 The present invention solves these problems, and it is possible to remove Au of any thickness formed on a substrate such as a semiconductor wafer without roughening the surface.
Alternatively, the present invention provides a method for selectively etching an Au alloy film.
以下、本発明について実施例を参考にして詳細
に述べる。ここでは、半導体ウエーハとしてｎ形
砒化ガリウム（GaAs）ウエーハを、電極材料と
してAu／Ge合金を用いた場合について述べる
が、本発明のエツチング方法は他の半導体ウエー
ハ表面上に形成されたAuまたはAu合金膜の場合
でも同様に適用することが出来る。 Hereinafter, the present invention will be described in detail with reference to Examples. Here, we will discuss the case where an n-type gallium arsenide (GaAs) wafer is used as the semiconductor wafer and an Au/Ge alloy is used as the electrode material. The same applies to alloy films.
第１図は本発明の実施例のフローチヤートであ
る。ｎ形GaAsウエーハ１を鏡面研磨した後、硫
酸：過酸化水素水：水（８：１：１容積比）でエ
ツチし、次いで真空蒸着法によりAu／Ge合金膜
２を付着する。蒸着条件は基板温度250℃、真空
度1.5×10-6Torr、膜厚は1.5μである。次に、レ
ジスト膜３を被着し、さらに写真蝕刻法により所
定の部分のレジスト膜を除去したのち露出する
Au／Ge合金膜のエツチングを開始する。エツチ
ング液としては、ヨードエツチ液に水溶性のカル
ボン酸を加えたものを用意する。ここでは、水溶
性のカルボン酸として酢酸を用い、ヨウ素、ヨウ
化カリ、水に対して所定の比率で、例えばヨウ素
25ｇ、ヨウ化カリ50ｇ、水50c.c.、酢酸500c.c.を混
合する。この容液を用いて室温でエツチングを行
うと、10分間で1.5のAu／Ge合金膜２をウエーハ
表面に荒れを与えることなく、選択的に除去する
事が出来た。勿論、このAu／Ge合金膜に対する
エツチング速度は第２図に示すように酢酸の添加
量に強く依存する。 FIG. 1 is a flowchart of an embodiment of the present invention. After mirror polishing the n-type GaAs wafer 1, it is etched with sulfuric acid:hydrogen peroxide:water (8:1:1 volume ratio), and then an Au/Ge alloy film 2 is deposited by vacuum evaporation. The deposition conditions were a substrate temperature of 250°C, a vacuum level of 1.5×10 -6 Torr, and a film thickness of 1.5μ. Next, a resist film 3 is deposited, and after removing the resist film at a predetermined portion by photolithography, the resist film 3 is exposed.
Start etching the Au/Ge alloy film. As the etching solution, a solution prepared by adding a water-soluble carboxylic acid to an iodine etching solution is prepared. Here, acetic acid is used as a water-soluble carboxylic acid, and a predetermined ratio of iodine, potassium iodide, and water is used, for example, iodine
Mix 25g of potassium iodide, 50g of potassium iodide, 50c.c. of water, and 500c.c. of acetic acid. When etching was carried out at room temperature using this solution, the 1.5 Au/Ge alloy film 2 could be selectively removed in 10 minutes without roughening the wafer surface. Of course, the etching rate for this Au/Ge alloy film strongly depends on the amount of acetic acid added, as shown in FIG.
酢酸の添加量が多くなるとエツチング速度は遅
くなり、500c.c.で1500Å／分程度となる。このエ
ツチング速度の減少は、酢酸の添加量の増大によ
つてAu／Ge合金膜の酸化力が緩和されることに
よるものと考えられる。一方、GaAsウエーハ表
面の荒れも、酢酸の添加によつて大幅に改善され
る。 As the amount of acetic acid added increases, the etching rate slows down to about 1500 Å/min at 500 c.c. This decrease in etching rate is thought to be due to the oxidation power of the Au/Ge alloy film being relaxed by increasing the amount of acetic acid added. On the other hand, the roughness of the GaAs wafer surface is also significantly improved by the addition of acetic acid.
第３図は荒れの程度を表わす図であり、縦軸に
はその組成の液に浸した場合のGaAs表面にエツ
チピツトが発生してくるまでの時間ｔcを記して
いる。酢酸を添加しない場合は１分間程度でエツ
チピツトは発生するが、500c.c.の酢酸を添加した
場合には20分間まで発生せず表面の荒れは認めら
れない。このように、酢酸の添加によつてGaAs
との反応がおさえられるため、前述したように選
択エツチ完了後直ちにウエーハを取り出す必要も
ない。ウエーハ内のエツチむらの修正、完全にエ
ツチング除去がなされたか否かの確認等もｔc
20分という充分の時間があるため完全に行うこと
が出来るため、工程管理上大きな利点となる。な
お、以上の説明では水溶性のカルボン酸として、
酢酸を用いたが、酢酸にかえて、シユウ酸、クエ
ン酸、ギ酸、リンゴ酸、コハク酸等でも同様の効
果が得られる。 FIG. 3 is a diagram showing the degree of roughness, and the vertical axis shows the time t c until etch pits are generated on the GaAs surface when immersed in a liquid of the given composition. When no acetic acid is added, etch pits occur in about 1 minute, but when 500 c.c. of acetic acid is added, they do not occur until 20 minutes and no surface roughness is observed. Thus, by adding acetic acid, GaAs
Since the reaction with the wafer is suppressed, there is no need to take out the wafer immediately after completion of selective etching as described above. We also correct etching unevenness within the wafer and check whether etching has been completely removed .
Since 20 minutes is ample time, it can be completed completely, which is a great advantage in terms of process control. In addition, in the above explanation, as water-soluble carboxylic acid,
Although acetic acid was used, similar effects can be obtained by using oxalic acid, citric acid, formic acid, malic acid, succinic acid, etc. instead of acetic acid.
以上のように、本発明のエツチング方法はヨウ
素、ヨウ化カリの水溶液に水溶性のカルボン酸を
添加した液を用いる事により、半導体ウエーハ表
面を荒すことなくAuまたはAu合金膜を選択的に
エツチングするものであり、その効果はすこぶる
大である。 As described above, the etching method of the present invention uses an aqueous solution of iodine and potassium iodide to which a water-soluble carboxylic acid is added, thereby selectively etching the Au or Au alloy film without roughening the semiconductor wafer surface. It does, and its effects are huge.
第１図は本発明のエツチング方法を説明するた
めのフローチヤート、第２図はAu／Ge合金膜に
対するエツチング速度の酢酸添加量依存性を示す
図、第３図はエツチピツトの発生時間と酢酸添加
量との関係を示す図である。
１……ｎ形GaAs ウエーハ、２……Au／Ge
合金膜、３……レジスト膜。
Fig. 1 is a flowchart for explaining the etching method of the present invention, Fig. 2 is a diagram showing the dependence of the etching rate on the Au/Ge alloy film on the amount of acetic acid added, and Fig. 3 is a diagram showing the generation time of etching pits and the addition of acetic acid. It is a figure showing the relationship with quantity. 1...n-type GaAs wafer, 2...Au/Ge
Alloy film, 3...resist film.
Claims (1)
チングにおいて、ヨウ素、ヨウ化カリの水溶液に
水溶性カルボン酸を添加したエツチング液を用い
ることを特徴とする金または金合金膜のエツチン
グ方法。 ２ エツチング液中の水溶性カルボン酸が、酢
酸、シユウ酸、クエン酸、ギ酸、リンゴ酸または
コハク酸のいずれかであることを特徴とする特許
請求の範囲第１項に記載の金または金合金膜のエ
ツチング方法。 ３ 基板が―族もしくは―族化合物半導
体のウエーハであることを特徴とする特許請求の
範囲第１項に記載の金または金合金膜のエツチン
グ方法。[Scope of Claims] 1. A gold or gold alloy film formed on a substrate surface, which is characterized in that an etching solution containing a water-soluble carboxylic acid added to an aqueous solution of iodine and potassium iodide is used in etching the gold or gold alloy film formed on the surface of a substrate. etching method. 2. Gold or gold alloy according to claim 1, wherein the water-soluble carboxylic acid in the etching solution is any one of acetic acid, oxalic acid, citric acid, formic acid, malic acid, or succinic acid. Membrane etching method. 3. The method for etching a gold or gold alloy film according to claim 1, wherein the substrate is a wafer of a - group or - group compound semiconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56113958A JPS5816074A (en) | 1981-07-20 | 1981-07-20 | Etching method for gold or gold alloy film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56113958A JPS5816074A (en) | 1981-07-20 | 1981-07-20 | Etching method for gold or gold alloy film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5816074A JPS5816074A (en) | 1983-01-29 |
| JPS6214033B2 true JPS6214033B2 (en) | 1987-03-31 |
Family
ID=14625464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56113958A Granted JPS5816074A (en) | 1981-07-20 | 1981-07-20 | Etching method for gold or gold alloy film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5816074A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60187299U (en) * | 1984-05-22 | 1985-12-11 | 安原鉄工株式会社 | Stop device for electric shutter with built-in drive device |
| JP4696565B2 (en) * | 2005-01-19 | 2011-06-08 | 三菱化学株式会社 | Etching solution and etching method |
| TW200823318A (en) * | 2006-08-28 | 2008-06-01 | Mitsubishi Chem Corp | Etchant and etching method |
-
1981
- 1981-07-20 JP JP56113958A patent/JPS5816074A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5816074A (en) | 1983-01-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4220706A (en) | Etchant solution containing HF-HnO3 -H2 SO4 -H2 O2 | |
| US3867218A (en) | Method of etching a pattern in a silicon nitride layer | |
| JPH0257339B2 (en) | ||
| US4256520A (en) | Etching of gallium stains in liquid phase epitoxy | |
| JPS6214033B2 (en) | ||
| US6173720B1 (en) | Process for treating a semiconductor substrate | |
| US3959098A (en) | Electrolytic etching of III - V compound semiconductors | |
| US4162337A (en) | Process for fabricating III-V semiconducting devices with electroless gold plating | |
| US5969419A (en) | Structure comprising platinum layer bound to a surface of a silicon oxide layer | |
| US5110765A (en) | Selective etch for GaAs-containing group III-V compounds | |
| US3947304A (en) | Etching of group III-V semiconductors | |
| JPH07105382B2 (en) | Fabrication process of semiconductor device including vapor phase etching | |
| JPH02196426A (en) | Selective etching method for arsenic aluminium gallium | |
| JPS6233310B2 (en) | ||
| US4597825A (en) | Intermediate passivation and cleaning of compound semiconductor surfaces | |
| JP3126262B2 (en) | Etching method of gold or gold alloy film | |
| JPS5946113B2 (en) | Semiconductor laser device and its manufacturing method | |
| JP2970236B2 (en) | GaAs wafer and method of manufacturing the same | |
| JP2730684B2 (en) | Method for manufacturing compound semiconductor | |
| JPH06196473A (en) | Surface treating method of semiconductor device | |
| US3424954A (en) | Silicon oxide tunnel diode structure and method of making same | |
| JPH0666309B2 (en) | Selective etching method | |
| JPS592173B2 (en) | Etching liquid for semiconductors | |
| JP2001044169A (en) | Semiconductor etchant, preparation method and etching method | |
| JP2794180B2 (en) | Method for manufacturing GaAs semiconductor device |