JPH0421321B2 - - Google Patents
Info
- Publication number
- JPH0421321B2 JPH0421321B2 JP62222894A JP22289487A JPH0421321B2 JP H0421321 B2 JPH0421321 B2 JP H0421321B2 JP 62222894 A JP62222894 A JP 62222894A JP 22289487 A JP22289487 A JP 22289487A JP H0421321 B2 JPH0421321 B2 JP H0421321B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- photoresist
- thermistor
- electrode
- metal thin
- 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 - Lifetime
Links
- 239000010408 film Substances 0.000 claims description 34
- 229920002120 photoresistant polymer Polymers 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 239000010409 thin film Substances 0.000 claims description 9
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 238000000151 deposition Methods 0.000 claims 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000002003 electrode paste Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- SWELZOZIOHGSPA-UHFFFAOYSA-N palladium silver Chemical compound [Pd].[Ag] SWELZOZIOHGSPA-UHFFFAOYSA-N 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000001552 radio frequency sputter deposition Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Apparatuses And Processes For Manufacturing Resistors (AREA)
- Thermistors And Varistors (AREA)
Description
〔産業上の利用分野〕
本発明は、サーミスタの表面の設けるサーミス
タ電極の形成方法に関するものである。
〔従来の技術〕
酸化物を混合焼結して得られるサーミスタは、
還元性雰囲気によつてその露出する表面が還元さ
れると、その部分は金属的様相を帯び、サーミス
タ特性が失われてしまうことが知られている。
このような変質層は不安定で、種々の環境条件
によつて特性が変動する。また、サーミスタの中
に占める変質層の割合が多いほど影響が大きい。
したがつて、サーミスタの露出した表面を各種
雰囲気、薬品などから保護することが必要になつ
てくる。この保護膜は製造工程の条件や使用面の
条件から、耐熱性のものであることが必要となつ
てくる。一般にはシリカが使用される。
〔発明が解決しようとする課題〕
ところが、サーミスタとするには、上記のよう
に絶縁性の保護膜があると、その一部を除去して
電極を形成する必要がある。この除去作業で、電
極を形成しようとする部分を除いて感光性樹脂で
絶縁膜の全面を非覆した後、感光させ、感光しな
かつた部分の絶縁膜を腐食液で溶解して除去しよ
うとすると、サーミスタ焼結体がその部分で露出
し、その腐食液で焼結体が腐食され、サーミスタ
特性の変質をもたらすという問題点がある。
従つて、電極形成部分は腐食液を使用しないで
絶縁膜の一部をはがさなければならない。
しかし、絶縁膜の剥離は手作業等では面倒であ
る。
本発明は、サーミスタ特性の変質をもたらさな
いで、電極を形成する方法を得ることを課題とす
るものである。
〔課題を解決するための手段〕
本発明のサーミスタ電極の形成方法は、上記の
ような問題点を解決するためになされたもので、
サーミスタ焼結体の表面の少なくとも一部分にフ
オトレジスト膜を形成し、露光し現像してフオト
レジストパターンを残存させ、そのフオトレジス
ト膜の上を含む全面に耐熱性無機絶縁膜を堆積
し、そのフオトレジストパターンをそのフオトレ
ジストパターンの上の耐熱性無機絶縁膜とともに
フオトレジスト除去液を用いて同時に除去し、全
面に金属薄膜を形成し、その全面の金属薄膜上に
フオトレジスト膜を形成し、露光し現像してフオ
トレジストパターンを残存させ、ついで電極とし
て残す部分以外の金属薄膜を除去し、その後に残
存フオトレジスト膜のみを除去して残存金属薄膜
を露出させることにより電極を形成するようにし
たものである。
ここでフオトレジスト膜を形成する感光性樹脂
は、市販品のもので、厚さを0.1から10μｍに塗布
する。厚さは堆積しようとする耐熱性無機絶縁膜
の厚さ以上あれば良いが、スライスしただけのサ
ーミスタ焼結体の表面は凸凹が多くピンホールの
のないフオトレジストパターンを得るには2μｍ
以上が望ましい。10μｍ以上の厚さではコストが
かさむばかりでなく、パターンの解像度も悪化す
る。
耐熱性無機絶縁膜は、SiO2、SiO、Si3N4、
SiO2-x、Al2O3、TiO2、Ta2O5を0.07〜7μｍの厚
さに付けた膜である。厚さは0.07μｍ以上あれば
保護の目的として充分である。多少のピンホール
は目立つた悪影響を与えない。厚すぎる場合は、
コストがかさむほか熱履歴によつてはクラツクや
剥落をもたらすので好ましくない。
〔実施例〕
第１図は本発明の実施例におけるサーミスタ電
極の形成方法を示す工程図で、先ずサーミスタ焼
結体をスライスして20mm×20mm×0.3mmのウエハ
ー状にする。〔第１図１
つぎに、そのウエハーａにネガ型フオトレジス
ト膜液ｂ（東京応化工業(株)製OMR85）を塗布し、
〔第１図２〕、ついで80℃で30分間乾燥した後、電
極を形成しようとする部分を紫外線露光し、現像
し厚さ2μｍ、怒径200μｍの残存したフオトレジ
スト膜パターンb′を形成する。〔第１図３〕
続いて、真空度10-2mmHgのアルゴン中で石英
板をターゲツトにして、13.56MHz・350Wの高周
波電力を印加し室温の基板上にRFスパツタリン
グ法によつて耐熱性無機絶縁膜のSiO2を0.1μｍの
厚さに堆積させる。〔第１図４〕
つぎに、120℃に熱したレジスト剥離液（東京
応化工業(株)製502A）に上記を浸漬し、フオトレ
ジストパターンb′とその上に堆積させたSiO2を同
時に除去する。〔第１図５〕
つぎに、電極とするニツケルを真空蒸着により
2μｍ堆積させる。〔第１図６〕
サーミスタ焼結体への電極材料には、従来、銀
−パラジウムペーストや銀ペーストなどが一般に
用いられているが、抵抗率が高く密着性に乏しい
欠点がある。蒸着法では遥かに多数の電極材料か
ら選択することができ、抵抗率も低く密着性も良
い。リード線へハンダ付けする場合、半田くわれ
によるニツケル層の目減りを考慮すると2μｍ程
度の厚さとするのが好ましい。
さらにその上に第１図(2)と同様にしてフオトレ
ジスト膜ｅを形成し〔第１図７〕、電極とする部
分を紫外線感光させ、現像し厚さ2μｍ、直径
300μｍのフオトレジスト膜e′を残す。〔第１図８〕
この後、塩酸１に対して純水１の容積比である
室温のエツチング液に上記を浸漬してフオトレジ
スト膜の付着した部分以外のニツケルを完全に溶
解し除去する〔第１図９〕、この際、裏面のサー
ミスタ焼結体表面を上記の塩酸水溶液によつて腐
食されないよう、保護する必要がある場合はフオ
トレジストなどを塗布しても良い。本実施例で
は、裏面を全面電極としたので保護を必要としな
かつた。
最後に残存フオトレジスト膜e′を前記と同様の
方法で除去する。〔第１図１０〕
以上のようにしてサーミスタ焼結体の表面を
SiO2で保護することにより、サーミスタ焼結体
の表面が腐食性の薬品に侵されることなく必要と
するパターンの電極を形成することができた。
このように、電極を部分的に形成したサーミス
タウエハーは、その後、下面にも上記と同様な方
法で電極を形成することが出来る。さらに、この
ようにして電極を形成したサーミスタウエハーは
ダイシングソーを用いて小さなチツプに分割さ
れ、それぞれのチツプはリード線等にハンダ接合
される。
〔発明の効果〕
本発明では、活性なサーミスタ焼結体の表面を
耐熱性無機絶縁膜によつて電極エツチング液や過
酷な環境から保護すると同時に、電気的接合をす
べき部分の耐熱性無機絶縁膜を腐食性の薬品を使
用しないで除去し、サーミスタ焼結体を全く損な
うことなく、高純度・底抵抗微細な電極パターン
を形成する手段を提供する。これにより、多数の
異なつた抵抗値を持つサーミスタを１チツプ上に
集積したり相互配線を行うことが可能となる。高
温で電極ペーストを焼き付ける従来技術において
見られた、そこに起因する特性の工程間変動や経
時変化などが、本発明になるサーミスタには全く
見られない。電極とサーミスタ焼結体との間の接
触抵抗も従来に比べ遥かに低く且つ、生産性や信
頼性に優れたサーミスタへの電極形成方法である
ので、本発明は産業の発達に大きく寄与する。
[Industrial Application Field] The present invention relates to a method for forming a thermistor electrode provided on the surface of a thermistor. [Prior art] Thermistors obtained by mixing and sintering oxides are
It is known that when the exposed surface is reduced by a reducing atmosphere, the exposed surface takes on a metallic appearance and loses its thermistor properties. Such an altered layer is unstable and its properties change depending on various environmental conditions. Furthermore, the greater the proportion of the altered layer in the thermistor, the greater the influence. Therefore, it becomes necessary to protect the exposed surface of the thermistor from various atmospheres, chemicals, and the like. This protective film needs to be heat resistant due to manufacturing process conditions and use conditions. Silica is commonly used. [Problems to be Solved by the Invention] However, in order to make a thermistor, if there is an insulating protective film as described above, it is necessary to remove a part of it to form an electrode. In this removal process, the entire surface of the insulating film is covered with photosensitive resin, except for the areas where electrodes are to be formed, and then the insulating film is exposed to light. This poses a problem in that the thermistor sintered body is exposed at that portion, and the sintered body is corroded by the corrosive liquid, resulting in deterioration of the thermistor characteristics. Therefore, a portion of the insulating film must be removed from the electrode forming portion without using a corrosive solution. However, peeling off the insulating film is troublesome if done manually or the like. An object of the present invention is to provide a method for forming electrodes without causing deterioration of thermistor characteristics. [Means for Solving the Problems] The method for forming a thermistor electrode of the present invention has been made in order to solve the above-mentioned problems.
A photoresist film is formed on at least a portion of the surface of the thermistor sintered body, exposed and developed to leave a photoresist pattern, and a heat-resistant inorganic insulating film is deposited on the entire surface including the top of the photoresist film. The resist pattern and the heat-resistant inorganic insulating film on the photoresist pattern are simultaneously removed using a photoresist removal solution to form a metal thin film on the entire surface, a photoresist film is formed on the metal thin film on the entire surface, and then exposed. The photoresist pattern was developed to remain, and then the metal thin film other than the portion to be left as an electrode was removed, and then only the remaining photoresist film was removed to expose the remaining metal thin film, thereby forming electrodes. It is something. The photosensitive resin used to form the photoresist film is a commercially available product and is applied to a thickness of 0.1 to 10 μm. The thickness should be at least the thickness of the heat-resistant inorganic insulating film to be deposited, but the surface of the thermistor sintered body that is just sliced is uneven, so to obtain a photoresist pattern without pinholes, a thickness of 2 μm is required.
The above is desirable. A thickness of 10 μm or more not only increases cost but also deteriorates pattern resolution. Heat-resistant inorganic insulating films include SiO 2 , SiO, Si 3 N 4 ,
The film is made of SiO 2-x , Al 2 O 3 , TiO 2 , and Ta 2 O 5 with a thickness of 0.07 to 7 μm. A thickness of 0.07 μm or more is sufficient for the purpose of protection. A few pinholes do not have any noticeable negative effects. If it's too thick,
This is not desirable because it increases cost and may cause cracking or peeling depending on the thermal history. [Example] FIG. 1 is a process diagram showing a method for forming a thermistor electrode in an example of the present invention. First, a thermistor sintered body is sliced into a wafer shape of 20 mm x 20 mm x 0.3 mm. [Figure 1 1 Next, a negative photoresist film solution b (OMR85 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to the wafer a,
[Fig. 1 2] After drying at 80°C for 30 minutes, the area where the electrodes are to be formed is exposed to ultraviolet light and developed to form a remaining photoresist film pattern b' with a thickness of 2 μm and an angular diameter of 200 μm. . [Fig. 1 3] Next, using the quartz plate as a target in an argon vacuum with a degree of vacuum of 10 -2 mmHg, high frequency power of 13.56 MHz and 350 W was applied, and a heat-resistant inorganic material was sputtered onto the substrate at room temperature using the RF sputtering method. An insulating film of SiO 2 is deposited to a thickness of 0.1 μm. [Figure 1 4] Next, the above is immersed in a resist stripping solution (502A manufactured by Tokyo Ohka Kogyo Co., Ltd.) heated to 120°C to simultaneously remove the photoresist pattern b' and the SiO 2 deposited on it. do. [Figure 1 5] Next, nickel to be used as an electrode is deposited by vacuum evaporation.
Deposit 2μm. [FIG. 1 6] Conventionally, silver-palladium paste, silver paste, and the like have been generally used as electrode materials for the thermistor sintered body, but these have the drawbacks of high resistivity and poor adhesion. With the vapor deposition method, it is possible to select from a much larger number of electrode materials, and the resistivity is low and adhesion is good. When soldering to lead wires, it is preferable to have a thickness of about 2 μm, considering the loss of the nickel layer due to solder cracks. Further, a photoresist film e is formed thereon in the same manner as in FIG. 1 (2) [FIG. 1 7], and the portion to be used as the electrode is exposed to ultraviolet light and developed to a thickness of 2 μm and a diameter of 2 μm.
A 300 μm photoresist film e′ is left. [FIG. 1 8] After this, the above is immersed in a room temperature etching solution having a volume ratio of 1 part hydrochloric acid to 1 part pure water to completely dissolve and remove the nickel except for the part where the photoresist film is attached. [FIG. 19] At this time, if it is necessary to protect the surface of the thermistor sintered body on the back side from being corroded by the aqueous hydrochloric acid solution, a photoresist or the like may be applied. In this example, since the entire back surface was used as an electrode, no protection was required. Finally, the remaining photoresist film e' is removed in the same manner as described above. [Fig. 1 10] As described above, the surface of the thermistor sintered body is
By protecting the thermistor sintered body with SiO 2 , we were able to form the required pattern of electrodes without the surface of the thermistor sintered body being attacked by corrosive chemicals. In this way, the thermistor wafer having electrodes partially formed thereon can then have electrodes formed on its lower surface in the same manner as described above. Further, the thermistor wafer with electrodes formed thereon is divided into small chips using a dicing saw, and each chip is soldered to a lead wire or the like. [Effects of the Invention] In the present invention, the surface of the active thermistor sintered body is protected from electrode etching liquid and harsh environments by a heat-resistant inorganic insulating film, and at the same time, the heat-resistant inorganic insulating film is used to protect the surface of the active thermistor sintered body from electrode etching liquid and harsh environments. To provide a means for removing a film without using corrosive chemicals and forming an electrode pattern of high purity and fine bottom resistance without damaging a thermistor sintered body at all. This makes it possible to integrate a large number of thermistors having different resistance values on one chip and to interconnect them. The thermistor of the present invention does not exhibit any inter-process variations or changes in characteristics over time that are caused by conventional techniques in which electrode paste is baked at high temperatures. The contact resistance between the electrode and the thermistor sintered body is also much lower than that of the conventional method, and the present invention greatly contributes to the development of industry because it is a method of forming electrodes in a thermistor with excellent productivity and reliability.
第１図は本発明の実施例におけるサーミスタ製
造の工程図である。
ａ…ウエハー、ｂ，ｃ…フオトレジスト膜、ｃ
…無機絶縁膜、ｄ…金属薄膜。
FIG. 1 is a process diagram for manufacturing a thermistor in an embodiment of the present invention. a... Wafer, b, c... Photoresist film, c
...Inorganic insulating film, d...Metal thin film.
Claims (1)
にフオトレジスト膜を形成し、露光し現像してフ
オトレジストパターンを残存させ、そのフオトレ
ジストパターンを残存させ、そのフオトレジスト
膜の上を含む全面に耐熱性無機絶縁膜を堆積し、
そのフオトレジストパターンをそのフオトレジス
トパターンの上の耐熱性無機絶縁膜とともにフオ
トレジスト除去液を用いて同時に除去し、全面に
金属薄膜を形成し、その全面の金属薄膜上にフオ
トレジスト膜を形成し、露光し現像してフオトレ
ジストパターンを残存させ、ついで電極として残
す部分以外の金属薄膜を除去し、その後に残存フ
オトレジスト膜のみを除去して残存金属薄膜を露
出させることを特徴とするサーミスタの電極形成
方法。1 A photoresist film is formed on at least a portion of the surface of the thermistor sintered body, exposed to light and developed to leave a photoresist pattern, and the photoresist pattern is left and the entire surface including the top of the photoresist film is heat resistant. Depositing an inorganic insulating film,
The photoresist pattern and the heat-resistant inorganic insulating film on the photoresist pattern are simultaneously removed using a photoresist removal solution to form a metal thin film on the entire surface, and a photoresist film is formed on the metal thin film on the entire surface. , a thermistor characterized by exposing and developing to leave a photoresist pattern, then removing the metal thin film other than the part to be left as an electrode, and then removing only the remaining photoresist film to expose the remaining metal thin film. Electrode formation method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22289487A JPS6466905A (en) | 1987-09-08 | 1987-09-08 | Manufacture of thermistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22289487A JPS6466905A (en) | 1987-09-08 | 1987-09-08 | Manufacture of thermistor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6466905A JPS6466905A (en) | 1989-03-13 |
| JPH0421321B2 true JPH0421321B2 (en) | 1992-04-09 |
Family
ID=16789531
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22289487A Granted JPS6466905A (en) | 1987-09-08 | 1987-09-08 | Manufacture of thermistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6466905A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61188502A (en) * | 1985-02-18 | 1986-08-22 | Matsushita Electric Ind Co Ltd | Preparation of optical waveguide |
-
1987
- 1987-09-08 JP JP22289487A patent/JPS6466905A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61188502A (en) * | 1985-02-18 | 1986-08-22 | Matsushita Electric Ind Co Ltd | Preparation of optical waveguide |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6466905A (en) | 1989-03-13 |
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