JPH03166359A - Formation of thin titanium film and thin titanium film for resistance temperature compensation - Google Patents
Formation of thin titanium film and thin titanium film for resistance temperature compensationInfo
- Publication number
- JPH03166359A JPH03166359A JP30609889A JP30609889A JPH03166359A JP H03166359 A JPH03166359 A JP H03166359A JP 30609889 A JP30609889 A JP 30609889A JP 30609889 A JP30609889 A JP 30609889A JP H03166359 A JPH03166359 A JP H03166359A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- film
- titanium thin
- sputtering
- resistance
- 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
- 239000010936 titanium Substances 0.000 title claims description 71
- 229910052719 titanium Inorganic materials 0.000 title claims description 71
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims description 69
- 230000015572 biosynthetic process Effects 0.000 title description 2
- 238000004544 sputter deposition Methods 0.000 claims abstract description 48
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 15
- 239000010703 silicon Substances 0.000 claims abstract description 15
- 238000000034 method Methods 0.000 claims abstract description 13
- 239000000758 substrate Substances 0.000 claims abstract description 6
- 239000010409 thin film Substances 0.000 claims description 89
- 239000013078 crystal Substances 0.000 claims description 7
- 239000000853 adhesive Substances 0.000 abstract 1
- 230000001070 adhesive effect Effects 0.000 abstract 1
- 239000010408 film Substances 0.000 description 39
- 239000004020 conductor Substances 0.000 description 18
- 238000001771 vacuum deposition Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000000206 photolithography Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 229910052814 silicon oxide Inorganic materials 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000002161 passivation Methods 0.000 description 2
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 2
- 150000003608 titanium Chemical class 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 239000011364 vaporized material Substances 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
Abstract
Description
【発明の詳細な説明】
【産業上の利用分野】
本発明は、スパッタ法によるチタン薄膜の形成方法の改
良及び応カセンサの抵抗温度補償に用いて好適なチタン
薄膜に関する。
〔従来の技術〕
近時、チタン薄膜は耐食性、耐熱性等の優れた性質を持
っていることから、種々の分野で利用されているが、例
えば半導体歪ゲージを用いた応力センサの抵抗温度補償
用抵抗として用いられている。即ち、圧カセンサ、歪み
センサ等として適用される応カセンサには半導体歪ゲー
ジが用いられているが、該半導体歪ゲージは負の抵抗温
度係数を有しており、ゲージ温度が上昇すると抵抗値が
下がる特性がある。このため、半導体歪ゲージには正の
抵抗温度係数を有する抵抗温度補償用のチタン薄膜抵抗
を接続し、半導体歪ゲージの抵抗値の降下分を補償する
ようになっている。
そして、従来技術によればダイヤフラムに形成したシリ
コン薄膜製絶縁膜上にチタン薄膜抵抗を形或する方法と
しては、真空蒸着法が一般的に用いられており、該真空
蒸着法によって形成したチタン薄膜にホトリソグラフィ
法によってパターン成形するようにしている。
〔発明が解決しようとする課題〕
ところで、真空蒸着法を用いてダイヤフラムのシリコン
薄膜上にチタン薄膜を形成する場合、次のような問題が
ある。即ち、真空蒸着法はチタンを加熱して発生させた
蒸発物をシリコン薄膜に付着させるため、付着強度がス
パッタ法、イオンプレーティング法、気相成長法に比較
して弱く、特に酸化ケイ素膜に対する付着力が弱く、し
かも均一に成膜されないという問題点がある。
このため、高い検出圧力を測定するのに用いられる高圧
用応カセンサに真空蒸着法を用いて抵抗温度補償用のチ
タン薄膜抵抗を形成した場合、応力測定時にダイヤフラ
ムが荷重を受けて変形するとき、チタン薄膜がシリコン
薄膜から剥離しやすく、信頼性に欠けるという欠点があ
る。
本発明は上述した従来技術の欠点に鑑みなされたもので
、シリコン膜に対する付着力が強く、しかも酸化物を含
まない高純度のチタン薄膜の形成方法及び抵抗温度補償
用抵抗に用いて好適なチタン薄膜を提供することを目的
とする。
〔課題を解決するための手段〕
上述した課題を解決するために、本発明による手段の特
徴は、スパッタ法を用いてシリコン基板上に形成するチ
タン薄膜の膜厚を０．２μｍ以上にすることにある。
また、スパッタ法には高周波スパッタ法を用い、スパッ
タ出力を略０．３ｋｗ、スパッタ時間１０分以上の条件
によりチタン薄膜を形成することにある。
さらに、抵抗温度補償用チタン薄膜は、膜厚を０．２μ
ｍ以上とし、結晶構造に（０１１）面を選択配向したこ
とを特徴とする。
〔作用〕
スパッタ法を用いることにより、チタン薄膜はシリコン
基板に対して強い付着力をもつ。そして、膜厚を０．２
μｍ以上に形成することにより、チタン薄膜には酸化物
を含まず、しかも抵抗温度係数を持つ。従って、該チタ
ン薄膜は応カセンサ、特に高圧用応カセンサの抵抗温度
補償に使用できる。
〔実施例〕
以下、本発明の実施例方法をダイヤフラム式応カセンサ
に適用する場合を例に挙げ、図面を参照しつつ説明する
。
第１図及び第２図はダイヤフラム式応カセンサを示す。
図において、１は金属材料、例えばステンレススチール
からなる高圧用のダイヤフラムで、該ダイヤフラム１は
薄肉円板状の起歪部１Ａと、該起歪部１Ａの外周に厚肉
円筒状に一体に形成された非起歪部ＩＢとからなってお
り、起歪部１Ａの図中下側面は矢示方向からの液圧を受
承する受圧面ＩＡ，になり、上側面は後述する絶縁膜２
を形成するための膜形成面ＩＡ２になっている。
２は前記起歪部ＩＡの膜形成面ＩＡｚ上に形或された絶
縁膜で、該絶縁膜２は例えばプラズマ−ＣＶＤ法、真空
蒸着法、スパッタ法等の適宜の成膜技術によって数μｍ
の厚さに形成された酸化ケイ素（Ｓｉｎｇ）膜からなっ
ている。
３Ａ，３Ｂ，３Ｃ，３Ｄは前記絶縁膜２上に形成された
４個の半導体歪ゲージからなるゲージ抵抗（以下ゲージ
抵抗３と総称する）で、該ゲージ抵抗３は例えばプラズ
マーＣＶＤ法によって絶縁膜２上に薄膜状に形成したケ
イ素基板にリン（Ｐ）又はホウ素（Ｂ）の不純物をドー
ピングしてゲージ用薄膜を形成した後、ホトリソグラフ
ィ法によってパターン形成されており、外力を受けて歪
んだときに比抵抗が変化するビエゾ抵抗素子として構成
されている。
４Ａ，４Ｂ，４Ｃ，４Ｄ，４Ｅ，４Ｆは前記ゲージ抵抗
３を接続してホイーストンブリッジ回路を構成する薄膜
導体（以下薄膜導体４と総称する）で、４Ａは第１のゲ
ージ抵抗３Ａの一端側に接続された第１の薄膜導体、４
Ｂは該ゲージ抵抗３Ａの他端側と第２のゲージ抵抗３Ｂ
の一端側に接続された第２の薄膜導体、４Ｃは該第２の
ゲージ抵抗３Ｂの他端側に接続された第３の薄膜導体を
示す。また、４Ｄは第３のゲージ抵抗３Ｃの一端側に接
続された第４の薄膜導体、４Ｅは該第３のゲージ抵抗３
Ｃの他端側と第４のゲージ抵抗３Ｄの一端側に接続され
た第５の薄膜導体で、４Ｆは該第４のゲージ抵抗３Ｄの
他端側に接続された第６の薄膜導体を示す。
これら薄膜導体４は絶縁膜２上に真空蒸着法を用いて金
（Ａｕ）、アルミニウム（ＡＪ２）、銅（Ｃｕ）等の良
導体材料からなる導体的薄膜を形成した後、ホトリソグ
ラフィ法によりパターン成形されている。そして、各薄
膜導体４Ａ，４Ｂ，４Ｃ，４Ｄ，４Ｅ，４Ｆの外側端部
は電源或は測定器の配線を接続するための接続用端子５
Ａ，５Ｂ，５Ｇ，５Ｄ，５Ｅ，５Ｆに形成されており、
端子５Ｃ，５Ｄは出力側の接続用端子になっている。
６は前記薄膜導体４のうち、第３の薄膜導体４Ｃと第４
の薄膜導体４Ｄとの間に並列接続された抵抗温度補償用
のチタン薄膜抵抗を示し、該チタン 薄膜抵抗６は高周
波スパッタ法を用いて後に詳述するように絶縁膜２上に
チタン薄膜を０．２μｍ以上の膜厚に形成した後、ホト
リソグラフィ法によってパターン成形されている。
７は酸化シリコン（Ｓｉｎ．）膜からなり、前記ゲージ
抵抗３、薄膜導体４及びチタン薄膜抵抗６を一体的に覆
うバッシベーション膜、８は前記パッシベーション膜７
を覆うようにダイヤフラムｌに固着された合成樹脂製の
ターミナルベースで、該ターミナルベース８には配線導
出穴８Ａ，８Ａが形成されている。そして、該ターミナ
ルベース８に設けられた接続端子９．１０は前記接続用
端子５Ｃ，５Ｄと配線１１．１２を介してそれぞれ接続
されると共に、出力用のリード線１３，１４が接続され
ている。
更に、ｌ５はターミナルベース８の外周側を囲むように
ダイヤフラム１のフランジ部に嵌着された外力バーで、
該外力バー１５内はターミナルベース８を密封するよう
に絶縁製樹脂１６によってモールドされている。
応カセンサは上述の如く構成されており、端子５Ｂ、５
Ｅと端子５Ｃ （５Ａ） 、５Ｄ （５Ｆ）とを用いて
ホイートストンブリッジ回路を形成し、端子５Ｃ，５Ｄ
間に電圧計、電流計等の測定器を接続し、端子５Ｂ，５
Ｅ間に電源を接続してダイヤフラム１の起歪部ｌＡの歪
を測定する。起歪部ＩＡが無負荷状態であればゲージ抵
抗３の電気抵抗は変化しないから、端子５Ｃ，５Ｄ間に
電位差は生じなく、測定器に電流は流れない。一方ダイ
ヤフラム１に矢示方向の負荷が掛って起歪部ＩＡが歪む
と、ゲージ抵抗の電気抵抗が変化する結果、端子５Ｃ，
５Ｄ間に電位差が生じて電流が流れるため、測定器によ
り歪を測定することができる。そして、上述した測定中
チタン薄膜抵抗６はゲージ抵抗３の温度上昇に伴う抵抗
の減少を補償するようになっている。
そこで、次にシリコン製絶縁膜２上に該チタン薄膜抵抗
６を形成する方法について詳述する。
まず、抵抗温度補償用のチタン薄膜抵抗６を形成するに
は、抵抗値が２０〜２００Ωのチタン薄膜を形成する必
要があるが、高周波スパッタ法によりこのようなチタン
薄膜を形成するためには、０．３〜０．５ｋｗのスパッ
タ出力が必要である（第３図参照）。しかし、０．４ｋ
ｗ以上のスパッタ出力でチタンを酸化シリコン膜上に成
膜すると、膜形成後にチッピング（チタン内の気泡の飛
び出しによる膜の剥離）が発生し、チタン薄膜の抵抗が
急増する現象が認められる。なお、スパッタ出力を０．
３ｋｗ未満とした場合には抵抗値が急増し、抵抗温度補
償には適用しえない。
そこで、スパッタ出力な略０．３ｋｗに設定し、スパッ
タ時間を変えてチタン薄膜を形成し、このチタン薄膜の
抵抗をスパッタ時間との関係から見ると、第４図に示す
ようにスパッタ時間を１０分以上に設定したチタン薄膜
が２０〜２００Ωの安定した抵抗を得ることができる。
次に，前述の如くスパッタ出力を略０． ３ｋｗ、スパ
ッタ時間を１０分以上に設定して形成したチタン薄膜の
膜厚（１）と抵抗温度係数（ＴＣＲ）との関係を第５図
に示す。抵抗温度係数（ＴＣＲ）は膜厚（１）が１．５
μｍになるまでは当該膜厚（１）に比例して増大し−、
膜厚が１．５μｍ以上になるとほぼ一定の値約２，００
０ｐｐｍになり、応カセンサの抵抗温度補償用チタン薄
膜としては十分な抵抗温度係数（ＴＣＲ）を得ることが
認められる。
更に、純チタン材及び高周波スパッタ法によりシリコン
膜上に形成したチタン薄膜の結晶構造をＸ線回折法によ
って測定した結果を第６図に示す。抵抗温度係数（ＴＣ
Ｒ）が２，ＯＯＯｐｐｍ以上である純チタン材（純Ｔｌ
）の結晶には、（０１１）、（０１０）、（００２）の
各面が明瞭に検出される。また、前述の如く抵抗温度係
数（ＴＣＲ）の大きい膜厚が１．５ｕｍのチタン薄膜（
Ｔ．）の結晶についても、純チタン材とは各面のＸ線の
ピーク強度比が異なるが（０１１）、（０１０）、（０
０２）の各面が明瞭に検出される。更に、膜厚が０．３
μｍのチタン薄膜（Ｔ．２）の結晶についても、（０１
１）（０１０）、（００２）の各面でピークを検出でき
る。
他方、抵抗温度係数（ＴＣＰ）の小さい薄膜が０４ １
μｍのチタン薄膜（Ｔ，３）の結晶については（０１０
）、（００２）の面は検出されるが、（０１１）面が全
く検出されず、しかも抵抗温度係数（ＴＣＲ）に悪影響
を及ぼす酸化チタン（Ｔ，Ｏ）の結晶面も検出されてい
る。なお、酸化チタン（Ｔ．Ｏ）はスパッタの途中で酸
素と反応して形成されるものである。
かくして、チタン薄膜が応カセンサの抵抗温度補償用抵
抗として必要な抵抗温度係数（ＴＣＲ）を得るためには
、（０１１）面を選択配向させることが必要であり、そ
のためにはチタン薄膜の膜厚を０．２μｍ以上に形成す
ればよいことになる。
叙上の如く本実施例によれば、真空蒸着法と比較して付
着力の強い高周波スパッタ法を用いてシリコン薄膜製の
絶縁膜２上にチタン薄膜を形或するから、応カセンサに
適用しても剥離することがないチタン薄膜抵抗６にする
ことができる。また、高周波スパッタ法によりチタン薄
膜を形成する場合、スパッタ出力を略０．３ｋｗ，スパ
ッタ時間を１０分以上に設定し、膜厚を０．２ｔＬｍ以
上に形或することにより、酸化物を含まない高純度のチ
タン薄膜を得ることができる。
なお、実施例はスパッタ法として高周波スパッタ法を用
いたが、他のスパッタ法も本発明に適用できるものであ
る。
Ｃ発明の効果〕
本発明は以上詳述した如くであって、膜厚を０．２μｍ
以上に形成することにより、酸化物を含まない高純度の
チタン薄膜を形成できる。また、本発明方法によればチ
タン薄膜はシリコン製絶縁膜に対して強い付着力を持つ
から、高圧用応カセンサの抵抗温度補償に用いることが
できる。
更に、スパッタ法の各条件を選択することによって任意
の抵抗温度係数を持ったチタン薄膜な形或でき、特にス
パッタ出力を略０．３ｋｗ、スパッタ時間１０分以上に
設定したとき、純チタン材と同等の抵抗値を持ったチタ
ン薄膜を形成できる。また、膜厚を０．２μｍ以上にし
，結晶構造に（０１１）面を選択配向したチタン薄膜は
高純度で、所望の抵抗温度係数を持った抵抗温度補償用
抵抗として用いることかできる。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved method for forming a titanium thin film by sputtering and to a titanium thin film suitable for use in resistance temperature compensation of a stress sensor. [Prior Art] Recently, titanium thin films have been used in various fields due to their excellent properties such as corrosion resistance and heat resistance. It is used as a resistor. That is, semiconductor strain gauges are used in stress sensors applied as pressure sensors, strain sensors, etc., but these semiconductor strain gauges have a negative temperature coefficient of resistance, and as the gauge temperature increases, the resistance value decreases. It has the characteristic of falling. For this reason, a titanium thin film resistor for resistance temperature compensation having a positive temperature coefficient of resistance is connected to the semiconductor strain gauge to compensate for the drop in the resistance value of the semiconductor strain gauge. According to the prior art, a vacuum evaporation method is generally used to form a titanium thin film resistor on a silicon thin film insulating film formed on a diaphragm. The pattern is formed using photolithography. [Problems to be Solved by the Invention] By the way, when forming a titanium thin film on a silicon thin film of a diaphragm using a vacuum evaporation method, there are the following problems. In other words, in the vacuum evaporation method, the vaporized material generated by heating titanium is attached to the silicon thin film, so the adhesion strength is weaker than that of the sputtering method, ion plating method, and vapor phase growth method. There are problems in that the adhesion is weak and the film is not formed uniformly. For this reason, when a titanium thin film resistor for resistance temperature compensation is formed using a vacuum evaporation method in a high pressure stress sensor used to measure high detection pressures, when the diaphragm deforms under load during stress measurement, The disadvantage is that the titanium thin film easily separates from the silicon thin film, resulting in a lack of reliability. The present invention has been made in view of the above-mentioned drawbacks of the prior art, and provides a method for forming a high-purity titanium thin film that has strong adhesion to a silicon film and does not contain any oxides, and a titanium film suitable for use in a resistor for resistance temperature compensation. The purpose is to provide thin films. [Means for Solving the Problems] In order to solve the above-mentioned problems, the feature of the means according to the present invention is that the thickness of the titanium thin film formed on the silicon substrate using the sputtering method is 0.2 μm or more. It is in. Furthermore, a high-frequency sputtering method is used for the sputtering method, and a titanium thin film is formed under conditions of a sputtering output of about 0.3 kW and a sputtering time of 10 minutes or more. Furthermore, the thickness of the titanium thin film for resistance temperature compensation is 0.2μ.
m or more, and the (011) plane is selectively oriented in the crystal structure. [Operation] By using the sputtering method, the titanium thin film has strong adhesion to the silicon substrate. Then, the film thickness was set to 0.2
By forming the titanium thin film to a thickness of μm or more, the titanium thin film does not contain any oxide and has a temperature coefficient of resistance. Therefore, the titanium thin film can be used for resistance temperature compensation of stress sensors, especially stress sensors for high pressure. [Example] Hereinafter, a case in which an example method of the present invention is applied to a diaphragm type stress sensor will be described with reference to the drawings. 1 and 2 show a diaphragm type force sensor. In the figure, 1 is a high-pressure diaphragm made of a metal material such as stainless steel, and the diaphragm 1 is formed integrally with a thin disk-shaped strain-generating portion 1A and a thick-walled cylindrical shape around the outer periphery of the strain-generating portion 1A. The lower side surface of the strain-generating portion 1A in the figure becomes a pressure receiving surface IA that receives the liquid pressure from the direction of the arrow, and the upper surface is an insulating film 2 which will be described later.
This is a film forming surface IA2 for forming a film. Reference numeral 2 denotes an insulating film formed on the film forming surface IAz of the strain-generating portion IA, and the insulating film 2 is formed into a thickness of several μm by an appropriate film forming technique such as plasma-CVD, vacuum evaporation, or sputtering.
It consists of a silicon oxide (Sing) film formed to a thickness of . 3A, 3B, 3C, and 3D are gauge resistors (hereinafter collectively referred to as gauge resistors 3) consisting of four semiconductor strain gauges formed on the insulating film 2, and the gauge resistors 3 are formed on the insulating film by, for example, a plasma-CVD method. After forming a thin film for a gauge by doping a silicon substrate formed in the form of a thin film on 2 with an impurity of phosphorus (P) or boron (B), a pattern is formed by photolithography, and it is distorted by external force. It is sometimes constructed as a viezoresistance element whose specific resistance changes. 4A, 4B, 4C, 4D, 4E, 4F are thin film conductors (hereinafter collectively referred to as thin film conductors 4) that connect the gauge resistor 3 to form a Wheatstone bridge circuit, and 4A is one end of the first gauge resistor 3A. a first thin film conductor connected to the side, 4
B is the other end side of the gauge resistor 3A and the second gauge resistor 3B.
A second thin film conductor 4C is connected to one end of the second gauge resistor 3B, and 4C is a third thin film conductor connected to the other end of the second gauge resistor 3B. Further, 4D is a fourth thin film conductor connected to one end side of the third gauge resistor 3C, and 4E is a fourth thin film conductor connected to one end side of the third gauge resistor 3C.
A fifth thin film conductor is connected to the other end of C and one end of the fourth gauge resistor 3D, and 4F is a sixth thin film conductor connected to the other end of the fourth gauge resistor 3D. . These thin film conductors 4 are formed by forming a conductive thin film made of a good conductive material such as gold (Au), aluminum (AJ2), copper (Cu), etc. on the insulating film 2 using a vacuum evaporation method, and then forming a pattern using a photolithography method. has been done. The outer ends of each of the thin film conductors 4A, 4B, 4C, 4D, 4E, and 4F are connection terminals 5 for connecting the wiring of a power source or a measuring instrument.
It is formed in A, 5B, 5G, 5D, 5E, 5F,
Terminals 5C and 5D are connection terminals on the output side. 6 is a third thin film conductor 4C and a fourth thin film conductor 4 among the thin film conductors 4.
A titanium thin film resistor 6 is connected in parallel with the thin film conductor 4D for resistance temperature compensation, and the titanium thin film resistor 6 is formed by depositing a titanium thin film on the insulating film 2 using a high frequency sputtering method as will be described in detail later. After forming the film to a thickness of 2 μm or more, it is patterned by photolithography. 7 is a passivation film made of a silicon oxide (Sin.) film and integrally covers the gauge resistor 3, the thin film conductor 4 and the titanium thin film resistor 6; 8 is the passivation film 7;
A terminal base made of synthetic resin is fixed to the diaphragm l so as to cover the terminal base 8, and wiring lead-out holes 8A, 8A are formed in the terminal base 8. The connection terminals 9.10 provided on the terminal base 8 are connected to the connection terminals 5C, 5D via wires 11.12, respectively, and output lead wires 13, 14 are connected thereto. . Furthermore, l5 is an external force bar fitted to the flange portion of the diaphragm 1 so as to surround the outer peripheral side of the terminal base 8,
The inside of the external force bar 15 is molded with an insulating resin 16 so as to seal the terminal base 8. The response sensor is configured as described above, and the terminals 5B, 5
Form a Wheatstone bridge circuit using E and terminals 5C (5A) and 5D (5F), and connect terminals 5C and 5D.
Connect a measuring device such as a voltmeter or ammeter between terminals 5B and 5.
A power source is connected between E and the strain in the strain-generating portion IA of the diaphragm 1 is measured. If the strain generating part IA is in an unloaded state, the electrical resistance of the gauge resistor 3 does not change, so no potential difference occurs between the terminals 5C and 5D, and no current flows through the measuring device. On the other hand, when a load is applied to the diaphragm 1 in the direction of the arrow and the strain generating part IA is distorted, the electrical resistance of the gauge resistor changes, and as a result, the terminals 5C,
Since a potential difference is generated between the 5Ds and a current flows, the strain can be measured with a measuring device. During measurement, the titanium thin film resistor 6 described above is designed to compensate for the decrease in resistance of the gauge resistor 3 as the temperature rises. Next, a method for forming the titanium thin film resistor 6 on the silicon insulating film 2 will be described in detail. First, in order to form the titanium thin film resistor 6 for resistance temperature compensation, it is necessary to form a titanium thin film with a resistance value of 20 to 200Ω, but in order to form such a titanium thin film by high frequency sputtering, A sputtering power of 0.3 to 0.5 kW is required (see Figure 3). However, 0.4k
When a titanium film is formed on a silicon oxide film with a sputtering power of more than W, chipping (film peeling due to the popping of air bubbles in titanium) occurs after film formation, and a phenomenon is observed in which the resistance of the titanium thin film rapidly increases. Note that the sputtering output was set to 0.
If it is less than 3 kW, the resistance value will increase rapidly and it cannot be applied to resistance temperature compensation. Therefore, a titanium thin film was formed by setting the sputtering output to approximately 0.3kw and varying the sputtering time, and looking at the resistance of this titanium thin film in terms of the relationship with the sputtering time, as shown in Figure 4, the sputtering time was 10 kW. A titanium thin film set to a resistance of 20 to 200Ω can be obtained with a stable resistance of 20 to 200Ω. Next, as mentioned above, the sputtering output was set to approximately 0. FIG. 5 shows the relationship between the film thickness (1) and the temperature coefficient of resistance (TCR) of a titanium thin film formed using a sputtering time of 3 kW and a sputtering time of 10 minutes or more. The temperature coefficient of resistance (TCR) is 1.5 when the film thickness (1) is
It increases in proportion to the film thickness (1) until it reaches μm.
When the film thickness is 1.5 μm or more, the value remains almost constant at approximately 2,00
0 ppm, and it is recognized that a sufficient temperature coefficient of resistance (TCR) can be obtained as a titanium thin film for resistance temperature compensation of a stress sensor. Further, FIG. 6 shows the results of measuring the crystal structure of a titanium thin film formed on a silicon film using a pure titanium material and a high frequency sputtering method using an X-ray diffraction method. Temperature coefficient of resistance (TC
Pure titanium material (pure Tl) with R) of 2,00ppm or more
), the (011), (010), and (002) planes are clearly detected. In addition, as mentioned above, a titanium thin film (1.5 um thick) with a large temperature coefficient of resistance (TCR) was used.
T. ) also differs from pure titanium material in the X-ray peak intensity ratio of each surface, but (011), (010), (0
02) are clearly detected. Furthermore, the film thickness is 0.3
Regarding the crystal of titanium thin film (T.2) of μm, (01
1) Peaks can be detected on each plane of (010) and (002). On the other hand, a thin film with a small temperature coefficient of resistance (TCP) is 04 1
For the crystal of the μm titanium thin film (T, 3), (010
), (002) planes are detected, but (011) planes are not detected at all, and moreover, a titanium oxide (T,O) crystal plane, which has a negative effect on the temperature coefficient of resistance (TCR), is also detected. Note that titanium oxide (T.O.) is formed by reacting with oxygen during sputtering. Thus, in order for the titanium thin film to obtain the temperature coefficient of resistance (TCR) necessary for the resistance temperature compensation resistor of the stress sensor, it is necessary to selectively orient the (011) plane, and for this purpose, the thickness of the titanium thin film must be adjusted. This means that it is sufficient to form the layer to a thickness of 0.2 μm or more. As described above, according to this embodiment, the titanium thin film is formed on the insulating film 2 made of silicon thin film using the high frequency sputtering method, which has a stronger adhesion force than the vacuum evaporation method, so it can be applied to a force sensor. The titanium thin film resistor 6 can be made into a titanium thin film resistor 6 that will not peel off even if In addition, when forming a titanium thin film by high-frequency sputtering, the sputtering output is set to approximately 0.3kW, the sputtering time is set to 10 minutes or more, and the film thickness is formed to 0.2tLm or more, so that it does not contain oxides. A highly pure titanium thin film can be obtained. In addition, although the high frequency sputtering method was used as the sputtering method in the embodiment, other sputtering methods can also be applied to the present invention. C Effect of the invention] The present invention is as detailed above, and the film thickness is 0.2 μm.
By forming as described above, a highly pure titanium thin film containing no oxide can be formed. Furthermore, according to the method of the present invention, the titanium thin film has strong adhesion to the silicon insulating film, so it can be used for resistance temperature compensation of high pressure stress sensors. Furthermore, by selecting various conditions of the sputtering method, it is possible to form a titanium thin film with an arbitrary temperature coefficient of resistance.Especially when the sputtering output is set to about 0.3kW and the sputtering time is set to 10 minutes or more, it is possible to form a titanium thin film with an arbitrary temperature coefficient of resistance. A titanium thin film with the same resistance value can be formed. Further, a titanium thin film having a film thickness of 0.2 μm or more and having a (011) plane selectively oriented in the crystal structure has high purity and can be used as a resistance temperature compensation resistor having a desired resistance temperature coefficient.
第１図は本発明の実施例に係るスパッタ法により形成し
たチタン薄膜抵抗を用いた応カセンサの縦断面図、第２
図は第１図中の絶縁膜上の実装状態を示す拡大平面図，
第３図はチタン薄膜抵抗とスパッタ出力との関係を示す
線図、第４図はスパッタ出力をＯ− ３ｋｗに設定した
ときのスパッタ時間とチタン薄膜抵抗との関係を示す線
図、第５図はスパッタ出力０．３ｋｗのときにおけるチ
タン薄膜厚さと抵抗温度係数との関係を示す線図、第６
図は純チタン材及び膜厚の異なるチタン薄膜のＸ線回折
結果を示す線図である。
１・・・ダイヤフラム、２・・・絶縁膜、３Ａ，３Ｂ，
３Ｃ，３Ｄ・・・ゲージ抵抗、４Ａ，４Ｂ，４Ｃ，４Ｄ
，４Ｅ，４Ｆ・・・薄膜導体、６・・・チタン薄膜抵抗
。FIG. 1 is a longitudinal sectional view of a stress sensor using a titanium thin film resistor formed by sputtering according to an embodiment of the present invention, and FIG.
The figure is an enlarged plan view showing the mounting state on the insulating film in Figure 1.
Figure 3 is a diagram showing the relationship between titanium thin film resistance and sputtering output, Figure 4 is a diagram showing the relationship between sputtering time and titanium thin film resistance when sputtering output is set to O-3kW, and Figure 5 is a diagram showing the relationship between titanium thin film resistance and sputtering output. is a diagram showing the relationship between the titanium thin film thickness and the temperature coefficient of resistance when the sputtering output is 0.3 kW.
The figure is a diagram showing the X-ray diffraction results of pure titanium material and titanium thin films with different thicknesses. 1...Diaphragm, 2...Insulating film, 3A, 3B,
3C, 3D... Gauge resistance, 4A, 4B, 4C, 4D
, 4E, 4F... thin film conductor, 6... titanium thin film resistor.
Claims (3)
を形成するチタン薄膜の形成方法において、前記チタン
薄膜の膜厚を０．２μｍ以上に形成することを特徴とす
るチタン薄膜の形成方法。(1) A method for forming a titanium thin film in which a titanium thin film is formed on a silicon substrate using a sputtering method, the method comprising forming the titanium thin film to a thickness of 0.2 μm or more.
ッタ出力を略０．３ｋｗ、スパッタ時間１０分以上の条
件により形成するようにした特許請求の範囲１項記載の
チタン薄膜の形成方法。(2) The method for forming a titanium thin film according to claim 1, wherein the titanium thin film is formed using a high-frequency sputtering method under conditions of a sputtering output of about 0.3 kW and a sputtering time of 10 minutes or more.
面が選択配向されている抵抗温度補償用チタン薄膜。(3) Thin film is 0.2 μm or more and has a crystal structure (011)
A titanium thin film for resistance temperature compensation with selectively oriented surfaces.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30609889A JPH03166359A (en) | 1989-11-24 | 1989-11-24 | Formation of thin titanium film and thin titanium film for resistance temperature compensation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30609889A JPH03166359A (en) | 1989-11-24 | 1989-11-24 | Formation of thin titanium film and thin titanium film for resistance temperature compensation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03166359A true JPH03166359A (en) | 1991-07-18 |
Family
ID=17953014
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30609889A Pending JPH03166359A (en) | 1989-11-24 | 1989-11-24 | Formation of thin titanium film and thin titanium film for resistance temperature compensation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03166359A (en) |
-
1989
- 1989-11-24 JP JP30609889A patent/JPH03166359A/en active Pending
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