JPH0719904B2 - Method for manufacturing photodetection element - Google Patents
Method for manufacturing photodetection elementInfo
- Publication number
- JPH0719904B2 JPH0719904B2 JP63007309A JP730988A JPH0719904B2 JP H0719904 B2 JPH0719904 B2 JP H0719904B2 JP 63007309 A JP63007309 A JP 63007309A JP 730988 A JP730988 A JP 730988A JP H0719904 B2 JPH0719904 B2 JP H0719904B2
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- Prior art keywords
- oxide film
- film
- anodic oxide
- manufacturing
- wafer
- Prior art date
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、光検知素子の製造方法に係り、特に光導電
型赤外線検知素子等の保護膜としての陽極酸化膜を高品
位に形成できる光検知素子の製造方法に関するものであ
る。Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a photo-detecting element, and more particularly to a method for forming a high-quality anodic oxide film as a protective film for a photoconductive infrared detecting element or the like. The present invention relates to a method for manufacturing a sensing element.
第１図（ａ）は光導電型赤外線検知素子の構造の一例を
示す平面図、第１図（ｂ）は、同図（ａ）に示した切断
線Ａ−Ａの断面図である。この図において、１は赤外線
検知素子用ウエハ（以下単にウエハと称す）で、高抵抗
の基板1aと化合物半導体1bとから構成されている。化合
物半導体1bは、例えばｎ型のcdxHg1-xTe等が該当し、高
抵抗の基板1a上にエピタキシャル成長などの方法によっ
て所定の厚さに形成される。ただし、ｘは０≦ｘ≦１な
る組成比を表す。cdxHg1-xTeはバンドギャップの狭い半
導帯で、組成比ｘ＝0.3のものは３〜５μｍ波帯の、ま
た、組成比Ｘ＝0.2のものは10μｍ波帯の赤外線検知素
子として広く利用されている。２は溝で、高抵抗の基板
1aに達するか、それよりも深く掘るものとする。３は金
属蒸着膜、3aは電極で、金属蒸着膜３のなかで電極とし
て用いられる部分を示す。金属蒸着膜３は、例えば蒸着
したCr上にさらにAuを蒸着した（以下Cr/Auと記す）金
属膜である。４は受光面、５は陽極酸化膜で、受光面４
表面の安定化のために形成された膜で、その形成により
直下の化合物半導体1bがN+化される。このため、赤外線
入射により発生する過剰少数キャリアの正孔が表面に拡
散しにくくなり表面結合が防止される。６は反射防止膜
で、材質は、例えばZnSで10μｍ波帯の赤外線検知素子
の場合その厚さは1.1μｍである。FIG. 1 (a) is a plan view showing an example of the structure of the photoconductive infrared detecting element, and FIG. 1 (b) is a sectional view taken along the line AA shown in FIG. 1 (a). In the figure, reference numeral 1 denotes a wafer for infrared detection element (hereinafter simply referred to as a wafer), which is composed of a high-resistance substrate 1a and a compound semiconductor 1b. The compound semiconductor 1b is, for example, n-type cd x Hg 1-x Te or the like, and is formed in a predetermined thickness on the high-resistance substrate 1a by a method such as epitaxial growth. However, x represents a composition ratio of 0 ≦ x ≦ 1. cd x Hg 1-x Te is a semi-conducting band with a narrow bandgap, the composition ratio x = 0.3 is a 3 to 5 μm wave band, and the composition ratio X = 0.2 is a 10 μm wave band infrared detector. Widely used. 2 is a groove, a high resistance substrate
Reach 1a or dig deeper than that. Denoted at 3 is a metal vapor deposition film, and denoted at 3a is an electrode, which is a portion of the metal vapor deposition film 3 used as an electrode. The metal vapor deposition film 3 is, for example, a metal film in which Au is further vapor deposited on vapor deposited Cr (hereinafter referred to as Cr / Au). 4 is a light receiving surface, 5 is an anodic oxide film, and the light receiving surface 4
This is a film formed for stabilizing the surface, and the compound semiconductor 1b immediately below is converted to N + by the formation thereof. Therefore, the holes of the excess minority carriers generated by the incidence of infrared rays are less likely to diffuse to the surface, and surface coupling is prevented. Reference numeral 6 denotes an antireflection film, which is made of ZnS and has a thickness of 1.1 μm in the case of an infrared detection element in the 10 μm waveband.
次に第２図（ａ），（ｂ），（ｃ）を参照しながら第１
図（ａ），（ｂ）に示した光導電型の赤外線検知素子の
従来の製造方法について説明する。なお、各図中の同一
符号は同一または相当部分を示す。Next, referring to FIGS. 2 (a), (b) and (c), the first
A conventional method of manufacturing the photoconductive type infrared detecting element shown in FIGS. The same reference numerals in each drawing indicate the same or corresponding parts.
まず、高抵抗の基板1a上に化合物半導体1bを形成し、ウ
エハ１を作成する。次に、ウエハ１を写真製版法を用い
てエッチングし、第２図（ａ）に示すようなコの字型の
溝２を形成する。続いて、ウエハ１をブロムメタノール
液を用いて軽くエッチングして清浄にした後、Cr/Auを
蒸着し、写真製版法を用いて第２図（ｂ）に示すような
形状の金属蒸着膜３を形成する。なお、金属蒸着膜３の
形成は、リフトオフ法を用いてもおこなえる。この場合
には、写真製版法を用いて所定形状のレジスト膜を形成
した後、ウエハ１の露出した面をブロムメタノール液を
用いてエッチングし、清浄にしたうえでCr/Auを蒸着す
る。その後、不要部分のレジスト膜を剥離すると同時に
レジスト膜上のCr/Auをも除去することにより第２図
（ｂ）に示した金属蒸着膜３が得られる。First, the compound semiconductor 1b is formed on the high resistance substrate 1a, and the wafer 1 is prepared. Next, the wafer 1 is etched by a photolithography method to form a U-shaped groove 2 as shown in FIG. 2 (a). Subsequently, the wafer 1 is lightly etched with a bromine methanol solution to be cleaned, and then Cr / Au is vapor-deposited, and a metal vapor deposition film 3 having a shape as shown in FIG. To form. The metal vapor deposition film 3 can also be formed by using the lift-off method. In this case, after a resist film having a predetermined shape is formed by using a photolithography method, the exposed surface of the wafer 1 is etched with a bromine methanol solution to be cleaned, and then Cr / Au is vapor-deposited. After that, the unnecessary portion of the resist film is peeled off, and at the same time Cr / Au on the resist film is also removed, whereby the metal vapor deposition film 3 shown in FIG. 2B is obtained.
次にウエハ１をプラズマ陽極酸化し、陽極酸化膜５を形
成する。この時、金属蒸着膜３がマスクとなるので、第
２図（ｂ）に示す金属蒸着膜３以外の露出している部
分、すなわち化合物半導体1b部分にのみ陽極酸化膜５が
形成される。Next, the wafer 1 is plasma anodized to form an anodized film 5. At this time, since the metal vapor deposition film 3 serves as a mask, the anodic oxide film 5 is formed only on the exposed portion other than the metal vapor deposition film 3 shown in FIG. 2B, that is, the compound semiconductor 1b portion.
上記のように金属蒸着膜３をマスクとして陽極酸化膜５
を選択的に形成した後、反射防止膜６を蒸着、スパッタ
等の方法によりウエハ１の表面全面に形成する。As described above, the metal oxide film 3 is used as a mask to form the anodic oxide film 5.
Then, the antireflection film 6 is formed on the entire surface of the wafer 1 by a method such as vapor deposition and sputtering.
次に、写真製版法を用いて反射防止膜６をエッチング
し、第２図（ｃ）に示すような電極3aを形成し、最後に
ダイシングソーを用いウエハ１を切断分割し、第１図
（ａ），（ｂ）に示したような赤外線検知素子を製造し
ていた。Next, the antireflection film 6 is etched by using a photoengraving method to form an electrode 3a as shown in FIG. 2 (c), and finally the wafer 1 is cut and divided by using a dicing saw, and then, as shown in FIG. The infrared detecting element as shown in a) and (b) was manufactured.
しかし、以上説明したような従来の光検知素子の製造方
法では、受光面４の反射防止膜６に剥離が起こったり、
剥離しない場合でも素子特性が劣化するという問題点が
あった。However, in the conventional method for manufacturing the photodetector as described above, the antireflection film 6 on the light receiving surface 4 is peeled off,
There is a problem that the element characteristics are deteriorated even when the element is not peeled off.
これは、金属蒸着膜３形成時の写真製版等によって汚染
された化合物半導体1bを直接陽極酸化して陽極酸化膜５
を形成したため、その膜質が劣っていること、あるいは
陽極酸化膜５の形成後、反射防止膜６の形成までに間が
あき、陽極酸化膜５の表面が汚染されるなどの理由によ
る。This is because the compound semiconductor 1b contaminated by photolithography during the formation of the metal vapor deposition film 3 is directly anodized and the anodic oxide film 5 is formed.
Therefore, the film quality is inferior, or there is a delay between the formation of the anodic oxide film 5 and the formation of the antireflection film 6, and the surface of the anodic oxide film 5 is contaminated.
この発明は、上記のような問題点を解決するためになさ
れたもので、膜質がよく表面が汚染されていない陽極酸
化膜の上に反射防止膜を形成することのできる光検知素
子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 order to solve the above problems, and is a method for manufacturing a photodetection element capable of forming an antireflection film on an anodic oxide film which has a good film quality and whose surface is not contaminated. The purpose is to provide.
この発明に係る光検知素子の製造方法は、受光面となる
化合物半導体上に陽極酸化膜を形成する酸化膜形成工程
と、この酸化膜形成工程で形成された陽極酸化膜を除去
する工程と、陽極酸化膜除去後に再度陽極酸化膜を形成
する工程と、再度形成された陽極酸化膜上に反射防止膜
を形成する工程とを含むものである。A method of manufacturing a photo-sensing element according to the present invention, an oxide film forming step of forming an anodic oxide film on a compound semiconductor to be a light receiving surface, and a step of removing the anodic oxide film formed in this oxide film forming step, It includes a step of forming an anodic oxide film again after removing the anodic oxide film, and a step of forming an antireflection film on the reformed anodic oxide film.
この発明においては、酸化膜形成工程で形成された陽極
酸化膜とともに素子上の汚染が除去され、素子上の汚染
を除去した後に膜質のよい陽極酸化膜が再形成され、再
形成された良質の酸化膜上に高品位の反射防止膜が形成
される。In the present invention, the contamination on the element is removed together with the anodic oxide film formed in the oxide film forming step, and after the contamination on the element is removed, the anodic oxide film of good film quality is re-formed, and the re-formed high-quality anodic oxide film is formed. A high-quality antireflection film is formed on the oxide film.
以下、この発明の光検知素子の製造方法の一実施例を第
１図および第２図を用いて説明する。なお、第１図およ
び第２図は従来例を説明する図とこの発明の一実施例を
説明する図とを兼ねている。An embodiment of the method for manufacturing the photo-detecting element of the present invention will be described below with reference to FIGS. 1 and 2. It should be noted that FIGS. 1 and 2 are both a diagram for explaining a conventional example and a diagram for explaining an embodiment of the present invention.
この発明の一実施例を示す光検知素子の製造方法におい
ては、陽極酸化膜５の形成までを従来例と全く同様にし
ておこなう。すなわち、高抵抗の基板1a上に化合物半導
体1bを形成し、ウエハ１を作成する。次にウエハ１を写
真製版法を用いてエッチングし、第２図（ａ）に示すよ
うなコの字型の溝２を形成する。続いて、ウエハ１をブ
ロムメタノール液を用いて軽くエッチングして清浄した
後、Cr/Auを蒸着し、写真製版法を用いて第２図（ｂ）
に示すような形状の金属蒸着膜３を形成する。次にウエ
ハ１をプラズマ陽極酸化し、第２図（ｂ）に示す化合物
半導体1b部分に陽極酸化膜５を形成する。In the method of manufacturing the photodetecting element according to the embodiment of the present invention, the formation of the anodic oxide film 5 is performed in exactly the same manner as the conventional example. That is, the compound semiconductor 1b is formed on the substrate 1a having a high resistance to form the wafer 1. Next, the wafer 1 is etched by the photolithography method to form a U-shaped groove 2 as shown in FIG. Subsequently, the wafer 1 is lightly etched with a bromine methanol solution to clean it, and then Cr / Au is vapor-deposited, and then the photolithography method is used to perform the etching as shown in FIG. 2 (b).
A metal vapor deposition film 3 having a shape as shown in is formed. Next, the wafer 1 is plasma-anodized to form an anodic oxide film 5 on the compound semiconductor 1b portion shown in FIG. 2B.
従来例においては、その後すぐに反射防止膜６を蒸着し
ていたが、この発明においては、一度形成した陽極酸化
膜５を除去した後、再度陽極酸化膜５の形成を行う。そ
の後、従来例と同様に反射防止膜６をウエハ１の表面全
面に形成する。In the conventional example, the antireflection film 6 was vapor-deposited immediately thereafter, but in the present invention, the anodic oxide film 5 that has been formed once is removed, and then the anodic oxide film 5 is formed again. After that, the antireflection film 6 is formed on the entire surface of the wafer 1 as in the conventional example.
陽極酸化膜５の除去は、例えば酒石酸水溶液等の弱酸を
用いておこなうことができる。陽極酸化膜５の厚さは40
0Å程度なので、酒石酸水溶液を用い１〜２分で除去で
きる。その後、充分水洗して酒石酸を除去し、イソプロ
ピルアルコールを用いて煮沸、乾燥する。The anodic oxide film 5 can be removed by using a weak acid such as an aqueous tartaric acid solution. The thickness of the anodic oxide film 5 is 40
Since it is about 0Å, it can be removed in 1 to 2 minutes using an aqueous tartaric acid solution. Then, it is thoroughly washed with water to remove tartaric acid, boiled and dried using isopropyl alcohol.
このようにして、はじめに形成した陽極酸化膜５を除去
すれば化合物半導体1b上の汚れも同時に除去され、再度
形成された陽極酸化膜５は質のよい膜となる。なお、陽
極酸化膜５の除去工程では、酒石酸を用いるので、金属
蒸着膜３等が侵されることはない。In this way, if the anodic oxide film 5 formed first is removed, the stains on the compound semiconductor 1b are also removed at the same time, and the reformed anodic oxide film 5 becomes a high quality film. Since tartaric acid is used in the step of removing the anodic oxide film 5, the metal vapor deposition film 3 and the like are not attacked.
また、工程の都合上、陽極酸化膜５の形成から反射防止
膜６の形成までに間があき、陽極酸化膜５の表面が汚染
された場合にも反射防止膜６の形成の直前に上記の陽極
酸化膜５の除去と再形成の工程を行うことにより、清浄
な陽極酸化膜５上に反射防止膜６を形成することができ
る。Further, due to the convenience of the process, there is a gap between the formation of the anodic oxide film 5 and the formation of the antireflection film 6, and even when the surface of the anodic oxide film 5 is contaminated, the above-mentioned process is performed immediately before the formation of the antireflection film 6. By performing the steps of removing and reforming the anodic oxide film 5, the antireflection film 6 can be formed on the clean anodic oxide film 5.
以上のようにして、陽極酸化膜５の形成，除去，再形
成，反射防止膜６の形成を行った後、従来例と同様にし
て写真製版法を用いて反射防止膜６をエッチングし第２
図（ｃ）に示すような電極3aを形成し、最後にダイシン
グソーを用いウエハ１を切断分割し、第１図（ａ），
（ｂ）に示すような赤外線検知素子を製造する。After the anodic oxide film 5 is formed, removed, re-formed, and the antireflection film 6 is formed as described above, the antireflection film 6 is etched by the photolithography method in the same manner as in the conventional example.
An electrode 3a as shown in FIG. 1C is formed, and finally, the wafer 1 is cut and divided by using a dicing saw.
An infrared detecting element as shown in (b) is manufactured.
なお、上記の実施例では化合物半導体1bとしてCdxHg1-x
Teを用いた赤外線検知素子の場合を示したが、この発明
の製造方法を他の半導体の酸化膜形成時に用いても上記
実施例と同様の効果を奏する。It should be noted that in the above-mentioned examples, Cd x Hg 1-x was used as the compound semiconductor 1b.
Although the case of the infrared detecting element using Te is shown, the same effect as that of the above-mentioned embodiment can be obtained even if the manufacturing method of the present invention is used when forming an oxide film of another semiconductor.
以上説明したようにこの発明は、受光面となる化合物半
導体上に陽極酸化膜を形成する酸化膜形成工程と、この
酸化膜形成工程で形成された陽極酸化膜を除去する工程
と、陽極酸化膜除去後に再度陽極酸化膜を形成する工程
と、再度形成された陽極酸化膜上に反射防止膜を形成す
る工程とを含むので、陽極酸化膜の除去により化合物半
導体の表面と、化合物半導体と陽極酸化膜の界面にある
汚れを同時に除去できるため、膜質がよく、表面が清浄
な陽極酸化膜を形成でき、その上に反射防止膜を形成で
きるので、反射防止膜の剥離がなくなり、歩留りが向上
し、また、特性のよい素子が得られる効果がある。As described above, the present invention is directed to an oxide film forming step of forming an anodic oxide film on a compound semiconductor serving as a light receiving surface, a step of removing the anodic oxide film formed in the oxide film forming step, and an anodic oxide film. Since the step of forming the anodized film again after the removal and the step of forming the antireflection film on the re-formed anodized film are included, the surface of the compound semiconductor, the compound semiconductor and the anodized film are removed by removing the anodized film. Since the dirt at the interface of the film can be removed at the same time, an anodized film with good film quality and a clean surface can be formed, and an antireflection film can be formed on it, so there is no peeling of the antireflection film and the yield is improved. Moreover, there is an effect that an element having excellent characteristics can be obtained.
第１図（ａ）は光導電型赤外線検知素子の構造の一例を
示す平面図、第１図（ｂ）は第１図（ａ）に示した切断
線Ａ−Ａの断面図、第２図（ａ）〜（ｃ）は、第１図
（ａ），（ｂ）に示した光導電型赤外線検知素子の製造
方法を説明するための図である。 図において、１はウエハ、1aは高抵抗の基板、1bは化合
物半導体、４は受光面、５は陽極酸化膜、６は反射防止
膜である。 なお、各図中の同一符号は同一または相当部分を示す。FIG. 1 (a) is a plan view showing an example of the structure of a photoconductive infrared detecting element, FIG. 1 (b) is a sectional view taken along the line AA shown in FIG. 1 (a), and FIG. (A)-(c) is a figure for demonstrating the manufacturing method of the photoconductive type infrared detection element shown to Fig.1 (a), (b). In the figure, 1 is a wafer, 1a is a high resistance substrate, 1b is a compound semiconductor, 4 is a light receiving surface, 5 is an anodic oxide film, and 6 is an antireflection film. The same reference numerals in each drawing indicate the same or corresponding parts.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 7210−4Ｍ Ｈ０１Ｌ 27/14 Ｋ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical indication 7210-4M H01L 27/14 K
Claims (1)
を形成する酸化膜形成工程と、この酸化膜形成工程で形
成された陽極酸化膜を除去する工程と、陽極酸化膜除去
後に再度陽極酸化膜を形成する工程と、再度形成された
陽極酸化膜上に反射防止膜を形成する工程とを含むこと
を特徴とする光検知素子の製造方法。1. An oxide film forming step of forming an anodic oxide film on a compound semiconductor serving as a light-receiving surface, a step of removing the anodic oxide film formed in this oxide film forming step, and an anodic oxide film again after the anodic oxide film is removed. A method of manufacturing a photodetecting element, comprising: a step of forming an oxide film; and a step of forming an antireflection film on a re-formed anodic oxide film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63007309A JPH0719904B2 (en) | 1988-01-14 | 1988-01-14 | Method for manufacturing photodetection element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63007309A JPH0719904B2 (en) | 1988-01-14 | 1988-01-14 | Method for manufacturing photodetection element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01183169A JPH01183169A (en) | 1989-07-20 |
| JPH0719904B2 true JPH0719904B2 (en) | 1995-03-06 |
Family
ID=11662403
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63007309A Expired - Lifetime JPH0719904B2 (en) | 1988-01-14 | 1988-01-14 | Method for manufacturing photodetection element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0719904B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110512254B (en) * | 2019-09-16 | 2021-09-17 | Oppo广东移动通信有限公司 | Shell of electronic equipment, manufacturing method of shell and electronic equipment |
-
1988
- 1988-01-14 JP JP63007309A patent/JPH0719904B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01183169A (en) | 1989-07-20 |
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