JPH0550272A - Method and device for removing thin film - Google Patents
Method and device for removing thin filmInfo
- Publication number
- JPH0550272A JPH0550272A JP3000596A JP59691A JPH0550272A JP H0550272 A JPH0550272 A JP H0550272A JP 3000596 A JP3000596 A JP 3000596A JP 59691 A JP59691 A JP 59691A JP H0550272 A JPH0550272 A JP H0550272A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- intensity
- laser light
- irradiation
- pulsed laser
- 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.)
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- Drying Of Semiconductors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、レーザ光を利用する薄
膜の除去方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film removing method using laser light.
【０００２】[0002]
【従来の技術】近年、レーザプロセス技術は、レジスト
プロセスを必要としないことから、半導体製造プロセス
の薄膜除去技術の中で、基板上の特定の箇所のみ局所的
に加工するプロセスにおいて工程を短縮できる利点か
ら、実用上重要な技術となっている。この中で、ＬＳＩ
の絶縁膜に用いられるＳｉＯ2 、ＳｉＮ、リンドープガ
ラス（ＰＳＧ）などの膜の除去技術は、多層配線を形成
する際の下層配線とのコンタクトホールを形成するため
に特に重要である。例えば、直接基板上に金属線を形成
するレーザＣＶＤ技術と、絶縁膜の局所除去技術とを組
み合わせれば、ＬＳＩの開発時の配線設計ミスをできあ
がったＬＳＩ上で修正することが可能となり、開発期間
の大幅な短縮図ることが出来る。2. Description of the Related Art In recent years, since a laser process technique does not require a resist process, the process can be shortened in a process of locally processing only a specific portion on a substrate in a thin film removing technique of a semiconductor manufacturing process. Due to its advantages, it is an important technology for practical use. Among these, LSI
The technique for removing a film such as SiO 2 , SiN, or phosphorus-doped glass (PSG) used for the insulating film is particularly important for forming a contact hole with a lower layer wiring when forming a multilayer wiring. For example, by combining a laser CVD technique for directly forming a metal line on a substrate with a local removal technique for an insulating film, it becomes possible to correct a wiring design mistake at the time of LSI development on the completed LSI. The period can be greatly shortened.
【０００３】上記の配線修正技術に関しては、例えば、
１９８９年９月発行の森重等による電気学会研究会資料
ＯＱＤ−８９−４９に詳しく記述されている。この論文
によれば、配線上の絶縁膜コンタクトホールを形成する
方法として、絶縁膜に透明な可視パルスレーザ光を照射
して、絶縁膜下の配線にレーザ光を吸収させ、配線上層
部の一部を気化させ、生じた圧力により間接的に絶縁膜
を蒸散させる手法が示されている。この手法では、他の
方法に比べ、装置構成を簡単にでき、かつＬＳＩ等で用
いられる多様な絶縁膜の種類に対応できるなどの優れた
特徴がある。しかしながら、この手法は原理的に配線の
一部の蒸散を前提とすることから、配線の損傷を如何に
最小限に抑えるかが課題となっていた。Regarding the above wiring correction technique, for example,
It is described in detail in the Institute of Electrical Engineers of Japan OQD-89-49 published by September, 1989 by Morishige et al. According to this paper, as a method of forming an insulating film contact hole on a wiring, the insulating film is irradiated with a transparent visible pulsed laser light so that the wiring under the insulating film absorbs the laser light and one of the wiring upper layer portions is exposed. There is shown a method of vaporizing the part and indirectly evaporating the insulating film by the generated pressure. Compared with other methods, this method has excellent features such that the device configuration can be simplified and various types of insulating films used in LSI and the like can be supported. However, since this method is premised on the evaporation of a part of the wiring in principle, there has been a problem how to minimize the damage of the wiring.
【０００４】[0004]
【発明が解決しようとする課題】上記論文によれば、パ
ルスレーザ光の照射強度を最適値のプラスマイナス１０
％程度の範囲に収めることが必要なことが指摘されてい
る。しかしながら、この手法では、最適照射強度が配線
の材質や幅や厚みなどの大きさに依存するために、配線
修正の局面で必要となる多様な配線構造の全てに渡っ
て、最適な照射強度で薄膜除去を行うことは容易ではな
かった。例えば、最適照射強度を大きく越えた強度で薄
膜除去を行うと、下地の配線が断線したり、また、照射
強度が十分でない場合には、加工が起こらなかったり、
きれいな加工形状が得られず、加工終了状態を光学的に
観察しただけでは、薄膜除去が終了したか否かを見分け
ることが容易ではないなどの問題を生じていた。According to the above-mentioned paper, the irradiation intensity of the pulsed laser light is ± 10 of the optimum value.
It has been pointed out that it is necessary to keep it within the range of about%. However, in this method, since the optimum irradiation intensity depends on the material of the wiring and the size of the wiring such as width and thickness, the optimum irradiation intensity can be obtained over all of the various wiring structures required in the wiring correction phase. It was not easy to remove the thin film. For example, if the thin film is removed with an intensity that greatly exceeds the optimum irradiation intensity, the underlying wiring will be broken, and if the irradiation intensity is not sufficient, processing will not occur,
There is a problem in that it is not easy to distinguish whether or not the thin film removal is completed by simply observing the processed state optically, because a clean processed shape cannot be obtained.
【０００５】本発明の目的は、従来の蒸散作用を利用し
た薄膜除去方法では、容易ではなかった、多様な配線構
造に対して、常に最適な照射強度で、薄膜除去を行う事
が可能で、また、加工の終了状態を確実に判定すること
ができる優れた薄膜除去方法を提供することにある。It is an object of the present invention to remove a thin film with a constant irradiation intensity, which is not easy with a conventional thin film removing method utilizing evaporation, for various wiring structures. Another object of the present invention is to provide an excellent thin film removal method capable of reliably determining the end state of processing.
【０００６】[0006]
【課題を解決するための手段】本出願の第１の発明は、
配線から成る吸収体層及び薄膜が順次形成された基板上
の所要部にパルスレーザ光を照射し、前記吸収体層の温
度上昇による体積膨張を利用して前記薄膜を除去する薄
膜除去方法において、該所要部の近傍に連続レーザ光を
照射し、該連続レーザ光の該近傍部からの戻り光と、入
射する該連続レーザ光を干渉させて、該パルスレーザ光
照射時に発生する超音波の強度を検出し、該超音波の強
度を基準値と比較して、薄膜除去の終状態を判定するこ
とを特徴とする薄膜除去方法である。The first invention of the present application is
In a thin film removal method of irradiating a required portion on a substrate on which an absorber layer and a thin film formed of wiring are sequentially formed, and removing the thin film by utilizing volume expansion due to temperature rise of the absorber layer, Intensity of ultrasonic waves generated during irradiation of the pulsed laser light by irradiating continuous laser light in the vicinity of the required portion and causing the return light from the vicinity of the continuous laser light and the incident continuous laser light to interfere with each other. Is detected and the intensity of the ultrasonic wave is compared with a reference value to determine the final state of thin film removal.
【０００７】本出願の第２の発明は、上述の薄膜除去方
法において、パルスレーザ光の照射強度を、薄膜除去の
起こるしきい照射強度より低い強度から、徐々に高めな
がら基板に照射すると共に、発生した超音波の強度と、
該パルスレーザ光の強度の比を測定し、該強度比が該低
い強度域の値から外れる該パルスレーザの照射強度を基
準として、薄膜除去に必要な最適照射強度値を、該基準
値に１．１から１．５の範囲の一定値を乗じた値として
求め、該最適照射強度での該パルスレーザ光の照射によ
り、薄膜除去を行うことを特徴とする薄膜除去方法であ
る。In a second invention of the present application, in the above-mentioned thin film removing method, the irradiation intensity of the pulsed laser light is gradually increased from the intensity lower than the threshold irradiation intensity at which thin film removal occurs, and the substrate is irradiated, The intensity of the generated ultrasonic waves,
The ratio of the intensity of the pulsed laser light is measured, and the optimum irradiation intensity value required for thin film removal is set to 1 by using the irradiation intensity of the pulsed laser whose intensity ratio deviates from the value in the low intensity range as a reference value. The thin film removing method is characterized in that a thin film is removed by irradiating the pulsed laser light with the optimum irradiation intensity as a value obtained by multiplying by a constant value in the range of 1 to 1.5.
【０００８】第３の本出願は、パルスレーザ光源と、加
工すべき基板を保持するＸ−Ｙステージと、該基板の所
要部にパルスレーザ光を照射しながら該基板上の照射部
を観察する照射観察光学系と、該パルスレーザ光の照射
強度を変化させる減衰器と、上記の各ユニットの動作を
制御する制御ユニットとから成る薄膜除去装置におい
て、該パルスレーザ光の照射部の近傍に、プローブレー
ザ光源からの連続レーザ光を照射し、該入射する連続レ
ーザ光と基板からの戻り光とを干渉させる干渉ユニット
と、該パルスレーザ光照射時に発生する、超音波による
該干渉ユニットからの出力信号の波高を記憶する波高記
憶ユニットと、該波高記憶ユニットからの出力と該パル
スレーザ光の照射強度の比を演算し、薄膜除去の起こる
しきい照射強度より低い強度域から徐々に該パルスレー
ザ光の照射強度を高めた時に観測される上記強度比の値
が、該低い強度域での比の値から外れる照射強度を基準
値として、この基準値に１．１から１．５の範囲の一定
値を乗じて得られる値を薄膜除去に必要な最適照射強度
として、薄膜除去を行う制御ユニットとを備えることを
特徴とする薄膜除去装置である。In the third application of the present invention, a pulse laser light source, an XY stage for holding a substrate to be processed, and an irradiation portion on the substrate are observed while irradiating a required portion of the substrate with the pulse laser light. An irradiation observation optical system, an attenuator that changes the irradiation intensity of the pulsed laser light, and a thin film removal device that includes a control unit that controls the operation of each unit, in the vicinity of the irradiation portion of the pulsed laser light, An interference unit that irradiates continuous laser light from a probe laser light source and causes the incident continuous laser light and the return light from the substrate to interfere with each other, and output from the interference unit due to ultrasonic waves generated when the pulsed laser light is irradiated. A pulse height storage unit that stores the pulse height of a signal, and calculates the ratio of the output from the pulse height storage unit and the irradiation intensity of the pulsed laser light to obtain a threshold irradiation intensity that causes thin film removal. The value of the intensity ratio observed when the irradiation intensity of the pulsed laser light is gradually increased from the low intensity range is set to 1 with respect to the irradiation intensity deviating from the value of the ratio in the low intensity range. The thin film removing apparatus is provided with a control unit for removing the thin film with a value obtained by multiplying a constant value in the range of 1 to 1.5 as the optimum irradiation intensity required for thin film removal.
【０００９】[0009]
【作用】本発明では、光音響法を利用して、非接触的
に、薄膜除去の過程もしくは、薄膜除去を行う被加工部
の特性を、それぞれモニタもしくは加工前に測定するこ
とが特徴である。光音響法はパルスレーザを基板上の薄
膜に照射することにより、薄膜の吸収係数を求めたり、
照射部から離れた位置で音響信号を検出することで、薄
膜中の音速を求める手法として知られている。本発明で
は、発生した超音波の強度に対するパルスレーザ光の強
度の比の値が、薄膜除去の起こるしきい照射強度よりず
っと低い照射強度領域から、薄膜除去の起こるしきい照
射強度よりわずかに低い照射強度域になった時に急激に
変化する現象と、薄膜除去の起こる照射強度では、しき
い照射強度より低い領域で発生する超音波の強度に比べ
２桁以上強力な超音波を発生することを新たに見いだし
たので、これらの特性を利用して最適照射強度の予測を
行うこと、もしくは、加工終了時の加工状態の良否を判
定することに適用した点が、従来の方法及び装置と原理
的に異なっている。The present invention is characterized by utilizing the photoacoustic method to measure the characteristics of the process of thin film removal or the portion to be processed for thin film removal in a non-contact manner before monitoring or before processing. .. The photoacoustic method irradiates the thin film on the substrate with a pulsed laser to obtain the absorption coefficient of the thin film,
It is known as a method for obtaining the sound velocity in a thin film by detecting an acoustic signal at a position away from the irradiation unit. In the present invention, the value of the ratio of the intensity of the pulsed laser light to the intensity of the generated ultrasonic waves is slightly lower than the threshold irradiation intensity at which thin film removal occurs from the irradiation intensity region that is much lower than the threshold irradiation intensity at which thin film removal occurs. The phenomenon that abruptly changes when it reaches the irradiation intensity range and the irradiation intensity at which thin film removal occurs is that it generates ultrasonic waves that are more than two orders of magnitude stronger than the intensity of ultrasonic waves generated in the region lower than the threshold irradiation intensity. Since it was newly found, the point that it was applied to predict the optimum irradiation intensity by utilizing these characteristics or to judge the quality of the processing state at the end of processing is the principle of the conventional method and apparatus. Is different.
【００１０】図２は、本発明の薄膜除去方法における薄
膜除去のためのパルスレーザ光１０３と測定用の連続レ
ーザ光１０１の基板１上の相対的位置関係を示す図であ
る。基板１上の配線１０６から反射された、連続レーザ
光の戻り光１０２は光路を逆に戻り、干渉ユニット１３
に入り、パルスレーザ光照射時に発生する基板上の配線
１０６の上下振動を検出する。FIG. 2 is a diagram showing the relative positional relationship on the substrate 1 of the pulsed laser light 103 for thin film removal and the continuous laser light 101 for measurement in the thin film removal method of the present invention. The return light 102 of the continuous laser light reflected from the wiring 106 on the substrate 1 returns to the reverse optical path, and the interference unit 13
Then, the up-and-down vibration of the wiring 106 on the substrate, which occurs when the pulsed laser light is irradiated, is detected.
【００１１】図３は、干渉ユニット１３で検出される超
音波のモニタ信号強度とパルスレーザ光の照射強度の関
係を示す。パルスレーザ光の強度が、薄膜除去のしきい
値に比べずっと低い照射強度域（Ａ）では、モニタ信号
強度は、パルスレーザ光照射強度と共に線形に増加する
が、薄膜除去のしきい強度よりわずかに照射強度が低い
領域（Ｂ）では、急に勾配が急になり、薄膜除去の起こ
る強度（Ｃ）ではモニタ信号強度は著しく大きくなるこ
とがわかった。（Ａ）の領域では、パルスレーザ照射に
より配線の局所的な熱膨張により超音波を発生するのに
対し、（Ｂ）の領域では、上層の薄膜の除去は起こらな
いものの、配線の部分的な気化が起こるために、熱膨張
分以外の成分が付加された状態、（Ｃ）の領域は、薄膜
除去に伴う破裂音が発生したためと推測される。本発明
では、領域（Ｂ）の立ち上がり点（ａ）を検出すること
で、最適加工強度を予測することや、薄膜除去時に発生
する超音波の強度の大きさから、薄膜除去の終状態の良
否を判定することができる。FIG. 3 shows the relationship between the monitor signal intensity of ultrasonic waves detected by the interference unit 13 and the irradiation intensity of pulsed laser light. In the irradiation intensity range (A) where the intensity of the pulsed laser light is much lower than the threshold for thin film removal, the monitor signal intensity increases linearly with the intensity of pulsed laser light irradiation, but is slightly lower than the threshold intensity for thin film removal. It was found that in the region (B) where the irradiation intensity was extremely low, the gradient became steep, and in the intensity (C) at which thin film removal occurred, the monitor signal intensity became significantly large. In the region (A), ultrasonic waves are generated by the local thermal expansion of the wiring due to the pulse laser irradiation, whereas in the region (B), the upper thin film is not removed, but the wiring is partially removed. It is speculated that in the region (C) where components other than the thermal expansion component are added due to vaporization, a burst sound is generated when the thin film is removed. In the present invention, by detecting the rising point (a) of the region (B), the optimum processing strength is predicted, and the quality of the final state of thin film removal is determined from the strength of the ultrasonic waves generated during thin film removal. Can be determined.
【００１２】[0012]
【実施例】以下本発明の実施例について図面を用いて詳
細に説明する。図１は、本発明の一実施例の構成図であ
る。この実施例はＡ１配線上のＳｉＮ膜への、コンタク
トホール用微細穴の形成に本発明を適用したものであ
る。Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. In this embodiment, the present invention is applied to the formation of contact hole fine holes in the SiN film on the A1 wiring.
【００１３】Ｎｄ：ＹＡＧレーザの第２高調波発生光源
（パルス幅５ｎｓ、５３２ｎｍ）から成るパルスレーザ
光源４からの出射光は、減衰器６で減衰させ、アパーチ
ャ２２でビームパターンを整形した後、第１のビームス
プリッタ１４、第２のビームスプリッタ１５を通り、レ
ンズ３で、基板１にアパーチャ２２のパターンを転写し
て照射する構成になっている。また、第２のビームスプ
リッタ１５、レンズ３は、照明光源２１とカメラ１９、
ＴＶ２０、第３のビームスプリッタ１６、第４のビーム
スプリッタ１７と接眼レンズ１８と組み合わせて、観察
光学系を構成している。基板１は、Ｘ−Ｙステージ２で
基板上の任意の位置にレーザ光照射部を移動できる構成
に成っている。Ｈｅ−Ｎｅレーザ光源んからなるプロー
ブレーザ光源８からの連続レーザ光は、第５のビームス
プリッタ１０で分割され、第１のビームスプリッタ１４
で反射され、第２のビームスプリッタ１５を透過してレ
ンズ３により、基板１上のパルスレーザ光照射部から１
０μｍ水平方向に離れた基板上の位置の配線に照射され
る様に構成されている。Light emitted from a pulse laser light source 4 composed of a second harmonic generation light source (pulse width 5 ns, 532 nm) of an Nd: YAG laser is attenuated by an attenuator 6 and a beam pattern is shaped by an aperture 22. The lens 3 transfers the pattern of the aperture 22 onto the substrate 1 through the first beam splitter 14 and the second beam splitter 15, and irradiates the pattern. Further, the second beam splitter 15 and the lens 3 include the illumination light source 21 and the camera 19,
A combination of the TV 20, the third beam splitter 16, the fourth beam splitter 17, and the eyepiece lens 18 constitutes an observation optical system. The substrate 1 is configured so that the laser light irradiation unit can be moved to an arbitrary position on the substrate by the XY stage 2. The continuous laser light from the probe laser light source 8 composed of a He-Ne laser light source is split by the fifth beam splitter 10 and is split by the first beam splitter 14.
From the pulse laser beam irradiation part on the substrate 1 by the lens 3 after being reflected by the second beam splitter 15.
It is configured to irradiate the wiring at a position on the substrate which is separated by 0 μm in the horizontal direction.
【００１４】基板１からの連続レーザ光の戻り光は、第
５のビームスプリッタ１０と反射板１２との間で、プロ
ーブレーザ光源８の光と干渉して、その強度変化は、Ｐ
ＩＮフォトダイオードの光検出器１１で検出される構成
となっている。プローブレーザ光源８、第５のビームス
プリッタ１０、反射板１２、光検出器１１からなるユニ
ットが干渉ユニット１３を構成し、この干渉ユニット１
３は、Ｙ−Ｚステージ９によって保持され、連続レーザ
光の基板１への照射位置が配線中央部等の平坦な箇所に
なるよう光路を微小に変化させ得る構成になっている。The return light of the continuous laser light from the substrate 1 interferes with the light of the probe laser light source 8 between the fifth beam splitter 10 and the reflecting plate 12, and its intensity change is P
It is configured to be detected by the photodetector 11 of the IN photodiode. A unit including the probe laser light source 8, the fifth beam splitter 10, the reflection plate 12, and the photodetector 11 constitutes an interference unit 13, and the interference unit 1
3 is configured to be held by the YZ stage 9 and capable of minutely changing the optical path so that the irradiation position of the continuous laser light on the substrate 1 becomes a flat portion such as the central portion of the wiring.
【００１５】光検出器１１の出力信号は、波高記憶ユニ
ット７で波高を記憶し、その波高データは制御ユニット
５に入力される構成となっている。制御ユニット５はパ
ルスレーザ光源４、減衰器６、アパーチャ２２、Ｘ−Ｙ
ステージ２、Ｙ−Ｚステージ９の動作を制御する。The output signal of the photodetector 11 stores the wave height in the wave height storage unit 7, and the wave height data is input to the control unit 5. The control unit 5 includes a pulse laser light source 4, an attenuator 6, an aperture 22 and an XY.
The operation of the stage 2 and the YZ stage 9 is controlled.
【００１６】次に本実施例における動作シーケンスを説
明する。Next, the operation sequence in this embodiment will be described.
【００１７】最初に、Ｘ−Ｙステージ２を動かして、パ
ルスレーザ光の照射位置が基板１上の薄膜除去を行いた
い配線（２μｍ幅×０，６μｍ厚）の表面になるよう基
板１を移動する。次に、その位置から１０μｍ離れた配
線表面の平坦部に、プローブレーザ光源８からの連続レ
ーザ光が反射されるようにＸ−Ｙステージ９を動かして
微調整する。次にアパーチャ２２の大きさを、基板上で
のパルスレーザ照射部の大きさが配線の幅と同じ２μｍ
×２μｍの短形となるよう設定する。薄膜除去の起こる
しきい照射強度は、この幅程度のＡ１配線であれば１０
０ＭＷ／ｃｍ2 付近にあるので、まずパルスレーザ光の
基板上での照射強度の初期値を、減衰器６により、５０
ＭＷ／ｃｍ2 に設定する。次にパルスレーザ光源の繰り
返しを５Ｈｚに設定して、一回ごとに照射強度を５ＭＷ
／ｃｍ2 ずつ増加させながら、パルスレーザ光照射時に
発生する調音波の強度を検出器１１により検出し、パル
スレーザ光の照射強度と発生する調音波の強度との関係
を測定する。得られる波形は、図３に示すような形状を
示すので、弱い照射強度域での勾配が変化するａ点を越
えた段階でパルスレーザ光の照射を一時停止し、次に照
射するパルスレーザ光の照射強度を、この配線の場合の
ａ点の照射強度に相当する９０ＭＷ／ｃｍ2 の１，３倍
の強度にあたる１１７ＭＷ／ｃｍ2 を最適照射強度に設
定し、パルスレーザ光を１ショット照射して、薄膜除去
を終了する。同様なシーケンスで配線の断面積が２μｍ
幅×１μｍの厚みの場合には、最適照射強度は１３０Ｍ
Ｗ／ｃｍ2 と予測された。このようにして、薄膜除去を
行い、薄膜除去に伴う配線の損傷を薄膜除去前後の配線
抵抗値の変化として評価したところ、従来の方法に比
べ、抵抗値の増加値は、種々の配線構造を持つ基板につ
き測定誤差範囲内の０．１Ω程度の非常に低い値に再現
性よく抑えることが可能となった。これらの結果は、従
来法では、ＬＳＩ作成時の配線データと薄膜除去の予備
実験から予測される最適値をもとに薄膜除去を行うが、
配線の抵抗増加値が数Ωの範囲内でばらつくこと、時々
加工が起こらない場合があるなど、再現性に問題があっ
たのに対し大きな改善が得られることを示している。First, the XY stage 2 is moved, and the substrate 1 is moved so that the irradiation position of the pulsed laser light is the surface of the wiring (2 μm width × 0.6 μm thickness) on the substrate 1 where thin film removal is desired. To do. Next, the XY stage 9 is moved and finely adjusted so that the continuous laser light from the probe laser light source 8 is reflected on the flat portion of the wiring surface 10 μm away from the position. Next, the size of the aperture 22 is set to 2 μm in which the size of the pulse laser irradiation portion on the substrate is the same as the width of the wiring.
It is set to have a rectangular shape of × 2 μm. The threshold irradiation intensity at which thin film removal occurs is 10 for A1 wiring of this width.
Since it is around 0 MW / cm 2 , first, the initial value of the irradiation intensity of the pulsed laser light on the substrate is set to 50 by the attenuator 6.
Set to MW / cm 2 . Next, set the repetition rate of the pulsed laser light source to 5 Hz, and set the irradiation intensity to 5 MW each time.
The intensity of the harmonic wave generated at the time of pulsed laser beam irradiation is detected by the detector 11 while increasing / cm 2 by 1 / cm 2, and the relationship between the pulsed laser beam irradiation intensity and the generated harmonic wave intensity is measured. Since the obtained waveform has a shape as shown in FIG. 3, the irradiation of the pulsed laser light is temporarily stopped at a stage beyond the point a where the gradient in the weak irradiation intensity range changes, and the pulsed laser light to be irradiated next is of the irradiation intensity, for the best illumination intensity 117MW / cm 2, which corresponds to 1,3 times the intensity of 90MW / cm 2, which corresponds to an irradiation intensity of a point in the case of the wiring, the pulsed laser beam 1 shot irradiated Then, the thin film removal is completed. Cross-sectional area of wiring is 2μm in the same sequence
Optimum irradiation intensity is 130M for width x 1μm thickness
It was predicted to be W / cm 2 . In this way, the thin film was removed, and the damage to the wiring due to the thin film removal was evaluated as the change in the wiring resistance value before and after the thin film removal. It was possible to reproducibly suppress the value of the substrate to a very low value of about 0.1Ω within the measurement error range. According to these results, in the conventional method, thin film removal is performed based on the wiring data at the time of LSI creation and the optimum value predicted from preliminary experiments of thin film removal.
It shows that the resistance increase value of the wiring varies within the range of several Ω, and that there is a problem in reproducibility that machining sometimes does not occur, but a great improvement can be obtained.
【００１８】また良好な薄膜除去が行われる場合に発生
する超音波の強度は、ａ点で観測されるモニタ信号強度
に比べ１００倍以上強くなることから、上記の最適照射
強度を加工前に測定しないで、加工を行った場合でも、
検出される超音波の強度の大きさから薄膜除去の終状態
の良否が簡単に判定できることがわかった。Further, since the intensity of the ultrasonic wave generated when the thin film is satisfactorily removed is 100 times stronger than the monitor signal intensity observed at the point a, the above-mentioned optimum irradiation intensity is measured before processing. Even if it is processed,
It was found that the quality of the final state of thin film removal can be easily determined from the intensity of the detected ultrasonic waves.
【００１９】[0019]
【発明の効果】以上述べたように、本発明によれば、多
様な配線構造に応じて、各々の構造における、損傷がす
くなく確実に薄膜除去を行うに必要な最適照射強度を所
望の加工すべき配線についてそれぞれ事前に測定して、
薄膜除去を行うことができるので、非常に高い歩留まり
で確実に薄膜除去を行うことが可能となる。また、薄膜
除去の終状態の良否を確実に判定できる利点がある。As described above, according to the present invention, in accordance with various wiring structures, the optimum irradiation intensity necessary for surely removing the thin film in each structure can be processed as desired. Measure each wiring in advance,
Since the thin film can be removed, the thin film can be surely removed with a very high yield. In addition, there is an advantage that the quality of the final state of thin film removal can be reliably determined.
【図１】本発明の一実施例の概略構成図、FIG. 1 is a schematic configuration diagram of an embodiment of the present invention,
【図２】本発明における薄膜除去を行うパルスレーザ光
とモニタ用連続レーザ光の基板上での照射位置の相対関
係を示す図、FIG. 2 is a diagram showing a relative relationship between irradiation positions on a substrate of pulsed laser light for removing a thin film and continuous laser light for monitoring according to the present invention;
【図３】パルスレーザ光照射強度とモニタ信号強度の関
係を示す図である。FIG. 3 is a diagram showing a relationship between a pulse laser beam irradiation intensity and a monitor signal intensity.
１ 基板 ２ Ｘ−Ｙステージ ３ レンズ ４ パルスレーザ光源 ５ 制御ユニット ６ 減衰器 ７ 波高記憶ユニット ８ プローブレーザ光源 ９ Ｘ−Ｙステージ １０ 第５のビームスプリツタ １１ 光検出器 １２ 反射板 １３ 干渉ユニット １４ 第１のビームスプリッタ １５ 第２のビームスプリッタ １６ 第３のビームスプリッタ １７ 第４のビームスプリッタ １８ 接眼レンズ １９ カメラ ２０ ＴＶ ２１ 照明光源 ２２ アパーチャ 1 substrate 2 XY stage 3 lens 4 pulse laser light source 5 control unit 6 attenuator 7 wave height memory unit 8 probe laser light source 9 XY stage 10 fifth beam splitter 11 photodetector 12 reflector 13 interference unit 14 First Beam Splitter 15 Second Beam Splitter 16 Third Beam Splitter 17 Fourth Beam Splitter 18 Eyepiece 19 Camera 20 TV 21 Illumination Light Source 22 Aperture
Claims (3)
成された基板上の所要部にパルスレーザ光を照射し、前
記吸収体層の温度上昇による体積膨張を利用して前記薄
膜を除去する薄膜除去方法において、該所要部の近傍に
連続レーザ光を照射し、該連続レーザ光の該近傍部から
の戻り光と、入射する該連続レーザ光を干渉させて、該
パルスレーザ光照射時に発生する超音波の強度を検出
し、該超音波の強度を基準値と比較して、薄膜除去の終
状態を判定することを特徴とする薄膜除去方法。1. A thin film is removed by irradiating a required portion on a substrate on which an absorber layer made of wiring and a thin film are sequentially formed, with a pulsed laser beam and utilizing volume expansion of the absorber layer due to temperature rise. In the thin film removal method, continuous laser light is irradiated in the vicinity of the required portion, and the continuous laser light that is incident is made to interfere with the return light of the continuous laser light from the vicinity, which occurs when the pulsed laser light is irradiated. The thin film removal method is characterized in that the intensity of the ultrasonic wave to be detected is detected and the intensity of the ultrasonic wave is compared with a reference value to determine the final state of thin film removal.
パルスレーザ光の照射強度を、薄膜除去の起こるしきい
照射強度より低い強度から、徐々に高めながら基板に照
射すると共に、発生した超音波の強度と、該パルスレー
ザ光の強度の比を測定し、該強度比が該低い強度域の値
から外れる該パルスレーザの照射強度を基準として、薄
膜除去に必要な最適照射強度値を、該基準値に１．１か
ら１．５の範囲の一定値を乗じた値として求め、該最適
照射強度での該パルスレーザ光の照射により、薄膜除去
を行うことを特徴とする薄膜除去方法。2. The thin film removing method according to claim 1,
The irradiation intensity of the pulsed laser light is gradually raised from the intensity lower than the threshold irradiation intensity at which thin film removal occurs, and the substrate is irradiated while the intensity of the generated ultrasonic wave and the intensity of the pulsed laser light are measured. An optimum irradiation intensity value required for thin film removal based on the irradiation intensity of the pulse laser whose intensity ratio deviates from the value in the low intensity range is a constant value in the range of 1.1 to 1.5. The thin film removing method is characterized in that the thin film is removed by irradiating the pulsed laser beam with the optimum irradiation intensity.
保持するＸ−Ｙステージと、該基板の所要部にパルスレ
ーザ光を照射しながら該基板上の照射部を観察する照射
観察光学系と、該パルスレーザ光の照射強度を変化させ
る減衰器と、上記の各ユニットの動作を制御する制御ユ
ニットとから成る薄膜除去装置において、該パルスレー
ザ光の照射部の近傍に、プローブレーザ光源からの連続
レーザ光を照射し、該入射する連続レーザ光と基板から
の戻り光とを干渉させる干渉ユニットと、該パルスレー
ザ光照射時に発生する、超音波による該干渉ユニットか
らの出力信号の波高を記憶する波高記憶ユニットと、該
波高記憶ユニットからの出力と該パルスレーザ光の照射
強度の比を演算し、薄膜除去の起こるしきい照射強度よ
り低い強度域から徐々に該パルスレーザ光の照射強度を
高めた時に観測される上記強度比の値が、該低い強度域
での比の値から外れる照射強度を基準値として、この基
準値に１．１から１．５の範囲の一定値を乗じて得られ
る値を薄膜除去に必要な最適照射強度として、薄膜除去
を行う制御ユニットとを備えることを特徴とする薄膜除
去装置。3. A pulse laser light source, an XY stage for holding a substrate to be processed, and an irradiation observation optical system for observing an irradiation portion on the substrate while irradiating a required portion of the substrate with the pulse laser light. In a thin film removal apparatus comprising an attenuator that changes the irradiation intensity of the pulsed laser light and a control unit that controls the operation of each unit described above, a thin film removal device is provided near the irradiation portion of the pulsed laser light from a probe laser light source. An interference unit that irradiates continuous laser light and interferes the incident continuous laser light with the return light from the substrate, and the wave height of the output signal from the interference unit that is generated by ultrasonic waves when irradiating the pulsed laser light is stored. And a ratio of the output from the wave height storage unit to the irradiation intensity of the pulsed laser light is calculated, and the intensity is gradually reduced from the intensity range lower than the threshold irradiation intensity at which thin film removal occurs. The value of the intensity ratio observed when the irradiation intensity of the pulsed laser light is increased is deviated from the value of the ratio in the low intensity region as a reference value, and 1.1 to 1 is added to the reference value. A thin film removing apparatus, comprising: a control unit for removing a thin film, with a value obtained by multiplying a constant value in the range of 0.5 as the optimum irradiation intensity required for thin film removal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3000596A JPH0550272A (en) | 1991-01-08 | 1991-01-08 | Method and device for removing thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3000596A JPH0550272A (en) | 1991-01-08 | 1991-01-08 | Method and device for removing thin film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0550272A true JPH0550272A (en) | 1993-03-02 |
Family
ID=11478115
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3000596A Pending JPH0550272A (en) | 1991-01-08 | 1991-01-08 | Method and device for removing thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0550272A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001212684A (en) * | 2000-02-02 | 2001-08-07 | Shibuya Kogyo Co Ltd | Via-hole processing method and its apparatus |
| JP2008177553A (en) * | 2006-12-20 | 2008-07-31 | Semiconductor Energy Lab Co Ltd | Method of manufacturing semiconductor device |
| CN102974937A (en) * | 2012-11-12 | 2013-03-20 | 中国科学院半导体研究所 | Laser machining device based on ultrasonic location and machining method |
| JP2013173160A (en) * | 2012-02-24 | 2013-09-05 | Disco Corp | Laser beam machining method and laser beam machining apparatus |
-
1991
- 1991-01-08 JP JP3000596A patent/JPH0550272A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001212684A (en) * | 2000-02-02 | 2001-08-07 | Shibuya Kogyo Co Ltd | Via-hole processing method and its apparatus |
| JP2008177553A (en) * | 2006-12-20 | 2008-07-31 | Semiconductor Energy Lab Co Ltd | Method of manufacturing semiconductor device |
| JP2013173160A (en) * | 2012-02-24 | 2013-09-05 | Disco Corp | Laser beam machining method and laser beam machining apparatus |
| CN102974937A (en) * | 2012-11-12 | 2013-03-20 | 中国科学院半导体研究所 | Laser machining device based on ultrasonic location and machining method |
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