JP3764794B2

JP3764794B2 - Multilayer thin film thickness measuring method, optical information recording medium manufacturing method and manufacturing apparatus

Info

Publication number: JP3764794B2
Application number: JP05124197A
Authority: JP
Inventors: 哲也秋山; 鋭二大野; 信夫赤平
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1997-03-06
Filing date: 1997-03-06
Publication date: 2006-04-12
Anticipated expiration: 2017-03-06
Also published as: JPH10253324A

Description

【０００１】
【発明の属する技術分野】
本発明は、基板上に設けられたそれぞれ光学定数の異なる複数の薄膜からなる多層薄膜の膜厚測定方法及びその膜厚測定方法を用いた光学情報記録媒体の製造方法及び光学情報記録媒体の製造装置に関する。
【０００２】
【従来の技術】
大容量で高密度なメモリーとして、書換えが可能な消去型と呼ばれる光学情報記録媒体の開発が進められている。この消去型の光学情報記録媒体の一つとして、アモルファス状態と結晶状態の間で相変化する薄膜を記録層として用い、レーザー光の照射による熱エネルギーによって情報の記録及び消去を行うものがある。
【０００３】
この記録層用の相変化材料としては、Ｇｅ，Ｓｂ，Ｔｅ，Ｉｎ等を主成分とする、例えばＧｅＳｂＴｅ，ＧｅＳｂＴｅＳｅ，ＩｎＳｂ，ＩｎＳｂＴｅ，ＩｎＳｂＴｅＡｇ等の合金膜が一般的に知られている。一般的に、情報の記録は記録層の部分的なアモルファス化によってマークを形成して行い、消去はこのアモルファスマークの結晶化によって行う。アモルファス化は記録層を融点以上に加熱した後に一定値以上の速さで冷却することによって行われる。また、結晶化は記録層を結晶化温度以上、融点以下の温度に加熱することによって行われる。
【０００４】
さらに、一般的には、記録層の上下に誘電体層が設けられている。この誘電体層の第１の目的は、瞬間的に融点以上に昇温する記録層の熱から基板を保護するとともに記録層の変形や破損を防止することである。また、第二の目的は、光干渉効果により記録情報の再生時に十分な信号強度を得ることである。さらに、第三の目的は、記録時に良好な形状のアモルファスマークを形成するのに適した冷却速度を実現することである。そのため、誘電体材料としては、十分な耐熱性、大きな屈折率、適度な熱伝導率等の特性が要求される。これらの条件を満たす材料として、例えばＺｎＳ−ＳｉＯ₂がある。
【０００５】
一般的な消去型の光学情報記録媒体１０の断面図を図２に示す。透明基板１は中心孔９及び複数の環状の案内溝２を有する円盤状である。透明基板１上には順に、ＺｎＳ−ＳｉＯ２薄膜からなる膜厚約１００nmの下引層３、ＧｅＳｂＴｅ合金薄膜からなる膜厚約２０nmの記録層４、ＺｎＳ−ＳｉＯ₂薄膜からなる膜厚約２０nmの上引層５、Ａｌ合金薄膜からなる膜厚約１００nmの反射層６が、スパッタリングによって形成され、さらにその上に樹脂保護層７が設けられている。この光学情報記録媒体の記録特性は各層の膜厚に大きく依存し、特に下引層３、記録層４の膜厚のばらつきによる影響が大きい。そのため、製造に当たっては、これらの膜厚を正確に管理する必要がある。
【０００６】
従来、上記光学情報記録媒体１０の主要部分である各薄膜層の製膜工程において、各層の膜厚管理のために、各層毎に所定の条件下でスパッタリングによって一定時間成膜したサンプルを定期的に作成し、その膜厚を段差計またはエリプソメータによって測定し、その測定結果から得られた成膜速度をもとに所望の膜厚が得られるよう成膜時間を補正する方法が採用されている。
【０００７】
【発明が解決しょうとする課題】
しかしながら、上記従来の方法によれば、光学情報記録媒体１０を構成する各薄膜層と同数の成膜速度測定用サンプルを作成し、各層毎にその膜厚を測定する必要があり、工程が複雑になると共に、成膜に時間を要するという問題点を有していた。また、バッチ式のスパッタリングによって成膜を行う場合、サンプル作成のバッチでは光学情報記録媒体を生産することができず、成膜速度の測定に伴う生産ロスが大きいという問題点を有していた。さらに、サンプル作成のために一時的に製造条件を変える必要があることや、各サンプルを段差計やエリプソメータでの測定に適した膜厚で成膜するため実際の媒体の構造とは異なる膜厚で成膜速度を算出することになり、誤差を伴うという問題点を有していた。
【０００８】
本発明は上記従来の問題点を解決するためになされたものであり、１回の測定で複数の薄膜層の膜厚測定が可能な多層薄膜の膜厚測定方法、及びその膜厚測定方法を用いて、成膜速度測定用サンプルの作成による生産ロスが少なく、製造条件の一時的な変更の必要のない光学情報記録媒体の製造方法及び光学情報記録媒体の製造装置を提供することを目的とする。
【０００９】
【課題を解決するための手段】
上記目的を達成するため、本発明の多層薄膜の膜厚測定方法は、それぞれ光学定数の異なる複数の薄膜からなる多層薄膜の膜厚測定方法であって、前記多層薄膜の分光反射率を測定した測定結果の極大値における波長を、あらかじめ定められた波長の標準値と比較し、前記測定結果の極大値における波長と前記波長の標準値との差異に基づいて、前記多層薄膜の分光反射率を測定する側から第１番目の薄膜の膜厚を求め、前記多層薄膜の分光反射率を測定した測定結果の極大値と極小値の反射率差を、あらかじめ定められた反射率差の標準値と比較し、前記測定結果の極大値と極小値の反射率差と前記反射率差の標準値との差異および前記第１番目の薄膜の膜厚に基づいて、前記多層薄膜の分光反射率を測定する側から第２番目の薄膜の膜厚を求める。
また、上記方法において、分光反射率を測定する際の各測定波長の間隔が５ｎｍ以下であることが好ましい。
【００１０】
一方、本発明における光学情報記録媒体の製造方法は、それぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造方法であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度と成膜時間により順次成膜する工程と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する工程と、前記多層薄膜の分光反射率を測定した測定結果の極大値における波長を、あらかじめ定められた波長の標準値と比較し、前記測定結果の極大値における波長と前記波長の標準値との差異に基づいて、前記多層薄膜の分光反射率を測定する側から第１番目の薄膜の膜厚を推定する工程と、前記第１番目の薄膜の膜厚の推定値と所望の膜厚との差異に応じて前記第１番目の薄膜の成膜速度及び成膜時間の少なくとも一方を補正する工程と、前記多層薄膜の分光反射率を測定した測定結果の極大値と極小値の反射率差を、あらかじめ定められた反射率差の標準値と比較し、前記測定結果の極大値と極小値の反射率差と前記反射率差の標準値との差異および推定した前記第１番目の薄膜の膜厚に基づいて、前記多層薄膜の分光反射率を測定する側から第２番目の薄膜の膜厚を推定する工程と、前記第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に応じて前記第２番目の薄膜の成膜速度及び成膜時間の少なくとも一方を補正する工程と、新たな基板上に前記複数の薄膜をそれぞれ補正された成膜速度及び成膜時間により順次成膜する工程とを備えている。
【００１１】
また、本発明における別の光学情報記録媒体の製造方法は、それぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造方法であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度と成膜時間により順次成膜する工程と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する工程と、前記多層薄膜の分光反射率を測定した測定結果の極大値における波長を、あらかじめ定められた波長の標準値と比較し、前記測定結果の極大値における波長と前記波長の標準値との差異に基づいて、前記多層薄膜の分光反射率を測定する側から第１番目の薄膜の膜厚を推定する工程と、前記第１番目の薄膜の膜厚の推定値と所望の膜厚との差異に基づいて基板又はサンプル片上に形成された多層薄膜の良否を判定し選別する工程と、前記多層薄膜の分光反射率を測定した測定結果の極大値と極小値の反射率差を、あらかじめ定められた反射率差の標準値と比較し、前記測定結果の極大値と極小値の反射率差と前記反射率差の標準値との差異および推定した前記第１番目の薄膜の膜厚に基づいて、前記多層薄膜の分光反射率を測定する側から第２番目の薄膜の膜厚を推定する工程と、前記第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に基づいて基板又はサンプル片上に形成された多層薄膜の良否を判定し選別する工程とを備えている。
【００１５】
また、上記各方法において、分光反射率を測定する際の各測定波長の間隔が５ｎｍ以下であることが好ましい。
【００１６】
また、本発明の光学情報記録媒体の製造装置は、それぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造装置であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度及び成膜時間により順次成膜する手段と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する手段と、前記多層薄膜の分光反射率を測定した測定結果の極大値における波長を、あらかじめ定められた波長の標準値と比較し、前記測定結果の極大値における波長と前記波長の標準値との差異に基づいて、前記多層薄膜の分光反射率を測定する側から第１番目の薄膜の膜厚を推定する手段と、前記第１番目の薄膜の膜厚の推定値と所望の膜厚との差異に応じて前記第１番目の薄膜の成膜速度及び成膜時間の少なくとも一方を補正する手段と、前記多層薄膜の分光反射率を測定した測定結果の極大値と極小値の反射率差を、あらかじめ定められた反射率差の標準値と比較し、前記測定結果の極大値と極小値の反射率差と前記反射率差の標準値との差異および推定した前記第１番目の薄膜の膜厚に基づいて、前記多層薄膜の分光反射率を測定する側から第２番目の薄膜の膜厚を推定する手段と、前記第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に応じて前記第２番目の薄膜の成膜速度及び成膜時間の少なくとも一方を補正する手段とを備えている。
【００１７】
また、本発明の別の光学情報記録媒体の製造装置は、それぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造装置であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度及び成膜時間により順次成膜する手段と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する手段と、前記多層薄膜の分光反射率を測定した測定結果の極大値における波長を、あらかじめ定められた波長の標準値と比較し、前記測定結果の極大値における波長と前記波長の標準値との差異に基づいて、前記多層薄膜の分光反射率を測定する側から第１番目の薄膜の膜厚を推定する手段と、前記第１番目の薄膜の膜厚の推定値と所望の膜厚との差異に基づいて基板又はサンプル片上に形成された多層薄膜の良否を判定し選別する手段と、前記多層薄膜の分光反射率を測定した測定結果の極大値と極小値の反射率差を、あらかじめ定められた反射率差の標準値と比較し、前記測定結果の極大値と極小値の反射率差と前記反射率差の標準値との差異および推定した前記第１番目の薄膜の膜厚に基づいて、前記多層薄膜の分光反射率を測定する側から第２番目の薄膜の膜厚を推定する手段と、前記第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に基づいて基板又はサンプル片上に形成された多層薄膜の良否を判定し選別する手段とを備えている。
【００２０】
また、上記各製造装置において、分光反射率を測定する際の各測定波長の間隔が５ｎｍ以下であることが好ましい。
【００２１】
【発明の実施の形態】
以下に、本発明の実施の形態を図面を参照しながら説明する。
【００２２】
本発明は、多層薄膜の各層の膜厚が変化すると分光反射率特性が変化することに着目し、各膜厚の変化に対応して分光反射率の極大点及び極小点の波長、反射率が特有の変化をすることに基づき、非破壊で多層薄膜の膜厚を測定するものである。
【００２３】
（第１の実施形態）
第１の実施形態は、多層薄膜の膜厚測定方法及びその膜厚測定方法を用いた光学情報記録媒体の製造方法に関するものであり、図１から図３を参照しつつ説明する。
【００２４】
図１は本発明の光学情報記録媒体の製造方法の要部を示すフローチャートである。図２は、前述の一般的な消去型の光学情報記録媒体の断面図である。また、図３は図２に示す構成を有する光学情報記録媒体の分光器による分光反射率の測定結果の一例を示す特性図である。
【００２５】
図１に示すように、まず、所定の条件下での各層の成膜時間を設定する（Ｓ１）。次に、この成膜時間にしたがって透明基板１上に下引層３、記録層４、上引層５、反射層６の順に成膜する（Ｓ１〜Ｓ５）。その後、分光器によって基板側からの分光反射率を測定波長範囲３５０〜８６０ｎｍ、波長間隔５ｎｍで測定する（Ｓ６）。図３にこの測定結果を示す。
【００２６】
次に、得られた分光反射率の極大点及び極小点を検出する（Ｓ７、Ｓ１３）。極大点の波長λを測定し（Ｓ８）、あらかじめ定められた標準値と比較し、その差異Δλを求める（Ｓ９）。これと平行して、極大点の反射率Ｒｍａｘ及び極小点の反射率Ｒｍｉｎを測定し、この反射率差Ｒｍａｘ−Ｒｍｉｎをあらかじめ定められた標準値と比較し、その差異Δ（Ｒｍａｘ−Ｒｍｉｎ）を求める（Ｓ１２、Ｓ１４、Ｓ１５、Ｓ１６）。ここで、標準値とは、各薄膜層が本来の設計値どうりの膜厚に形成されている場合の、分光反射率の極大点における波長及び極大点と極小点の反射率差をいう。これらはあらかじめ実験的に、あるいは計算上求めておくことができる。
【００２７】
次に、この測定結果をもとに、光学情報記録媒体１０の下引層３、記録層４の膜厚を算出する（Ｓ１０、Ｓ１７）。その算出方法は、以下の通りである。
【００２８】
下引層３の膜厚の標準値である１００ｎｍとの差ｘ（％）、記録層の膜厚の標準値である２０ｎｍとの差ｙ（％）を、以下に示す式（１）、（２）に従って算出する。
【００２９】
【数１】
Δλ＝ａｘ・・・（１）
【００３０】
【数２】
Δ（Ｒｍａｘ−Ｒｍｉｎ）＝ｂｘ＋ｃｙ・・・（２）
上記関係式は、下引層３が厚くなるとλが長波長側にずれ、薄くなると短波長側にずれ、下引層３の膜厚が一定であれば、記録層４及び上引層５の膜厚が変化してもλはほぼ一定であること、下引層３及び記録層４の膜厚が変化するとＲｍａｘ−Ｒｍｉｎが変化することから導かれたものである。
【００３１】
ただし、定数ａ＝２．５、ｂ＝−０．２２、ｃ＝０．３４である。ここで、ｘ、ｙは、各層膜厚の標準値との差異の標準値に対する比率である。各定数は、各層の膜厚を実験的に変化させた場合の分光反射率から求めることができる。また、各層薄膜の各波長における光学定数がわかっている場合には、多重干渉による反射率を算出することによって求めることもできる。この定数は各層膜厚の標準値によって異なる。
【００３２】
以上のようにして算出された各層の膜厚とその目標値との差異に応じて、所望の膜厚になるように成膜時間を変更して（Ｓ１１、Ｓ１８）、以後の生産を行う。
【００３３】
その結果、従来例における各層毎の成膜速度測定用サンプルを作成する必要が無く、生産ロスを低減することができる。特にバッチ式のスパッタリングによって成膜を行う場合にはその効果が顕著である。また、サンプル作成のために一時的に製造条件を変える必要がなく、２層の膜厚を同時に測定することにより成膜速度測定に要する時間が短縮できるため、製造ラインをより効率的に稼働することができる。さらに、実際の媒体の構造で膜厚を測定することができるので、製造した媒体の良否を判定し、選別することも可能である。
【００３４】
（第２の実施形態）
第２の実施形態は、上記多層薄膜の膜厚測定方法を用いた光学情報記録媒体の製造装置に関するものであり、図２及び図４を参照しつつ説明する。
【００３５】
図４に示す光学情報記録媒体の製造装置２０は、基板投入室１１、下引層成膜室１２、記録層成膜室１３、上引層成膜室１４、反射層成膜室１５、基板排出室１６、分光器１７、演算処理装置１８及び成膜条件制御装置１９で構成されている。
【００３６】
以上のように構成された光学情報記録媒体の製造装置について、その動作を説明する。基板投入室１１から光学情報記録媒体１０の透明基板１を投入し、下引層成膜室１２、記録層成膜室１３、上引層成膜室１４及び反射層成膜室１５において、それぞれ下引層３、記録層４、上引層５及び反射層６を順次形成する。その後、各層の薄膜が形成された基板１’を基板排出室１６から取り出す。各成膜室１２〜１５では、成膜条件制御装置１９によってガス流量、圧力、電力及び時間がそれぞれ所定の値に制御され、その条件の下でスパッタリングにより成膜が行われる。
【００３７】
分光器１７は、成膜された基板１’の成膜した面の反対側から分光反射率を測定する。演算処理装置１８は、例えばＣＰＵ、メモリ等を含み、分光器１７によって測定した分光反射率の極大点及び極小点を検出するプロセスと、極大点における波長λをあらかじめ定められた標準値と比較し、その差異Δλを求めるプロセスと、極大点と極小点におけるの反射率の差Ｒｍａｘ−Ｒｍｉｎをあらかじめ定められた標準値と比較し、その差異Δ（Ｒｍａｘ−Ｒｍｉｎ）を求めるプロセスと、前記Δλから上記所定の計算式により当該光学情報記録媒体１０の下引層３の膜厚と標準値との差異を算出するプロセスと、前記Δ（Ｒｍａｘ−Ｒｍｉｎ）と下引層３の膜厚とから上記所定の計算式により当該光記録媒体１０の記録層４の膜厚と標準値との差異を算出するプロセスと、各層の膜厚と標準値との差異をもとに所望の膜厚となる成膜時間を算出するプロセスを有しており、その計算結果に基づいて成膜条件制御装置１９で設定されている成膜時間を変更する。
【００３８】
この製造装置によれば、各層毎に成膜速度測定用サンプルを作成する必要が無く、生産ロスを低減することができる。特に、バッチ式のスパッタリングによって成膜を行う場合に、その効果が顕著である。また、サンプル作成のために一時的に製造条件を変える必要がなく、２層の膜厚を同時に測定することにより成膜速度測定に要する時間が短縮できるため、製造ラインをより効率的に稼働させることができる。さらに、実際の媒体の構造で膜厚を測定することができるので、製造した媒体の良否を判定し、選別することも可能である。
【００３９】
なお、上記各実施形態の説明において、各層の薄膜を所望の膜厚にするために成膜時間を変更したが、スパッタリングの電力、すなわち成膜速度を変更しても良い。また、光学情報記録媒体そのものの分光反射率を測定する代わりに、同時に別の基板に成膜したサンプルの分光反射率を測定しても良い。分光反射率の測定は、一定の製造枚数毎に行っても良いし、１枚毎に行っても良い。
【００４０】
また、分光反射率の測定波長間隔が大きいと膜厚の測定精度が悪くなる。例えば下引層３の場合λの差１０ｎｍが膜厚の約５％に相当する。したがって、必要とする膜厚の測定精度を５％とすると、測定波長間隔はその半分の５ｎｍ以下とすることが好ましい。
【００４１】
このように、本発明における光学情報記録媒体の第１の製造方法は、基板上に設けられたそれぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造方法であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度及び成膜時間により順次成膜する工程と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する工程と、前記分光反射率の測定結果から極値を検出しその極大値における波長とその標準値との差異に基づいて分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚を推定する工程と、分光反射率の極大値と極小値における反射率差の標準値との差異及び分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚から分光反射率を測定する側から第２番目の薄膜（記録層）の膜厚を推定する工程と、前記第１番目及び第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に応じて前記第１番目及び第２番目の薄膜の成膜速度及び成膜時間の少なくとも一方を補正する工程と、新たな基板上に前記複数の薄膜をそれぞれ補正された成膜速度及び成膜時間により順次成膜する工程とを備えている。すなわち、上記多層薄膜の膜厚測定方法を用いて、最初に成膜した基板又は基板と同時に成膜したサンプル片の膜厚を直接測定することにより、１回の測定で複数の薄膜の膜厚をそれぞれ測定することができ、膜厚測定に要する時間を短縮することができ、成膜速度測定に要する時間が短縮できる。また、実際の媒体の構造で膜厚を測定することができるので、サンプル作成のために一時的に製造条件を変える必要がない。したがって、製造ラインをより効率的に稼働させることができ、生産ロスを低減することができる。特に、バッチ式のスパッタリングにより成膜する場合に顕著な効果を奏する。
【００４２】
また、本発明における光学情報記録媒体の第２の製造方法は、基板上に設けられたそれぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造方法であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度及び成膜時間により順次成膜する工程と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する工程と、前記分光反射率の測定結果から極値を検出しその極大値における波長とその標準値との差異に基づいて分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚を推定する工程と、分光反射率の極大値と極小値における反射率差の標準値との差異及び分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚から分光反射率を測定する側から第２番目の薄膜（記録層）の膜厚を推定する工程と、前記第１番目及び第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に基づいて基板上に形成された多層薄膜の良否を判定し選別する工程とを備えている。したがって、実際に製造した光学情報記録媒体の膜厚を直接測定することができるので、製造した光学情報記録媒体の良否を判定し、選別することが可能である。
【００４３】
一方、本発明における光学情報記録媒体の第１の製造装置は、基板上に設けられたそれぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造装置であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度及び成膜時間により順次成膜する手段と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する手段と、前記分光反射率の測定結果から極値を検出しその極大値における波長とその標準値との差異に基づいて分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚を推定する手段と、分光反射率の極大値と極小値における反射率差の標準値との差異及び分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚から分光反射率を測定する側から第２番目の薄膜（記録層）の膜厚を推定する手段と、前記第１番目及び第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に応じて前記第１番目及び第２番目の薄膜の成膜速度及び成膜時間の少なくとも一方を補正する手段とを備えている。すなわち、上記多層薄膜の膜厚測定方法を用いて、最初に成膜した基板又は基板と同時に成膜したサンプル片の膜厚を測定し、測定値と標準値との差異に応じて各薄膜の成膜時間及び成膜速度の少なくとも一方を補正することにより、次回基板上に成膜される薄膜の膜厚を設計値により近づけることができる。さらに、この工程を繰り返すことにより、製造された光学情報記録媒体の各薄膜の膜厚の精度をより高くすることができる。
【００４４】
また、本発明における光学情報記録媒体の第２の製造装置は、基板上に設けられたそれぞれ光学定数の異なる複数の薄膜からなる多層薄膜を有する光学情報記録媒体の製造装置であって、基板又はサンプル片上に前記複数の薄膜をそれぞれ所定の成膜速度及び成膜時間により順次成膜する手段と、成膜後の基板又はサンプル片上の多層薄膜の分光反射率を測定する手段と、前記分光反射率の測定結果から極値を検出しその極大値における波長とその標準値との差異に基づいて分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚を推定する手段と、分光反射率の極大値と極小値における反射率差の標準値との差異及び分光反射率を測定する側から第１番目の薄膜（下引層）の膜厚から分光反射率を測定する側から第２番目の薄膜（記録層）の膜厚を推定する手段と、前記第１番目及び第２番目の薄膜の膜厚の推定値と所望の膜厚との差異に基づいて基板上に形成された多層薄膜の良否を判定し選別する手段とを備えている。したがって、実際に製造した光学情報記録媒体の膜厚を直接測定することができるので、製造した光学情報記録媒体の良否を判定し、選別することが可能である。
【００４５】
さらに、上記光学情報記録媒体の各製造方法及び製造装置において、分光反射率を測定する際の各測定波長の間隔を５ｎｍ以下とすることにより、膜厚の測定精度を約５％に維持することができる。
【００４６】
【発明の効果】
以上のように、本発明の光学情報記録媒体の膜厚測定造方法によれば、１回の測定で複数の薄膜の膜厚をそれぞれ測定することができ、膜厚測定に要する時間を短縮することができる。
【００４７】
また、実際の媒体の構造で膜厚を測定することができるので、サンプル作成のために一時的に製造条件を変える必要がなく、特に、バッチ式のスパッタリングにより成膜する場合に有効である。
【図面の簡単な説明】
【図１】本発明の光学情報記録媒体の製造方法の一実施形態の要部を示すフローチャート
【図２】一般的な光学情報記録媒体の構成を示す断面図
【図３】光学情報記録媒体の分光反射率と波長の関係を示す特性図
【図４】本発明の光学情報記録媒体の製造装置の一実施形態の要部を示す構成図
【符号の説明】
１透明基板
１’ 多層薄膜が形成された透明基板
２案内溝
３下引層
４記録層
５上引層
６反射層
７樹脂保護層
９中心孔
１０光学情報記録媒体
１１基板投入室
１２下引層成膜室
１３記録層成膜室
１４上引層成膜室
１５反射層成膜室
１６基板排出室
１７分光器
１８演算処理装置
１９成膜条件制御装置
２０光学情報記録媒体の製造装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring a film thickness of a multilayer thin film comprising a plurality of thin films each having a different optical constant provided on a substrate, a method for manufacturing an optical information recording medium using the film thickness measuring method, and a method for manufacturing an optical information recording medium Relates to the device.
[0002]
[Prior art]
As a large-capacity and high-density memory, an rewritable optical information recording medium called an erasable type is being developed. As one of the erasable optical information recording media, there is a recording medium that records and erases information by using thermal energy generated by laser light irradiation using a thin film that changes phase between an amorphous state and a crystalline state as a recording layer.
[0003]
As the phase change material for the recording layer, an alloy film such as GeSbTe, GeSbTeSe, InSb, InSbTe, InSbTeAg or the like mainly containing Ge, Sb, Te, In or the like is generally known. In general, information is recorded by forming a mark by partially amorphizing the recording layer, and erasing is performed by crystallization of the amorphous mark. Amorphization is performed by heating the recording layer to the melting point or higher and then cooling it at a speed equal to or higher than a certain value. Crystallization is performed by heating the recording layer to a temperature not lower than the crystallization temperature and not higher than the melting point.
[0004]
Furthermore, generally, dielectric layers are provided above and below the recording layer. The first purpose of this dielectric layer is to protect the substrate from the heat of the recording layer that instantaneously rises above the melting point and to prevent deformation and breakage of the recording layer. A second object is to obtain a sufficient signal strength at the time of reproducing recorded information by the optical interference effect. A third object is to realize a cooling rate suitable for forming an amorphous mark having a good shape during recording. Therefore, the dielectric material is required to have characteristics such as sufficient heat resistance, a large refractive index, and an appropriate thermal conductivity. As these conditions are satisfied materials, for example, a ZnS-SiO _2.
[0005]
A sectional view of a general erasable optical information recording medium 10 is shown in FIG. The transparent substrate 1 has a disk shape having a center hole 9 and a plurality of annular guide grooves 2. On the transparent substrate 1, an undercoat layer 3 made of a ZnS—SiO ₂ thin film, about 100 nm thick, a recording layer 4 made of GeSbTe alloy thin film about 20 nm thick, and a ZnS—SiO ₂ thin film made about 20 nm thick. An overcoat layer 5 and a reflective layer 6 made of an Al alloy thin film and having a thickness of about 100 nm are formed by sputtering, and a resin protective layer 7 is further provided thereon. The recording characteristics of this optical information recording medium greatly depend on the thickness of each layer, and are particularly affected by variations in the thickness of the undercoat layer 3 and the recording layer 4. For this reason, it is necessary to accurately control these film thicknesses in manufacturing.
[0006]
Conventionally, in the process of forming each thin film layer, which is the main part of the optical information recording medium 10, in order to control the film thickness of each layer, a sample formed for a predetermined time by sputtering under a predetermined condition for each layer is periodically used. The film thickness is measured by a step gauge or ellipsometer, and the film formation time is corrected so that a desired film thickness can be obtained based on the film formation speed obtained from the measurement result. .
[0007]
[Problems to be solved by the invention]
However, according to the above-described conventional method, it is necessary to create the same number of samples for film formation speed measurement as that of each thin film layer constituting the optical information recording medium 10, and to measure the film thickness for each layer. In addition, there is a problem that it takes time to form a film. Further, when film formation is performed by batch-type sputtering, an optical information recording medium cannot be produced in a batch of sample preparation, and there is a problem that production loss accompanying measurement of the film formation rate is large. In addition, it is necessary to temporarily change the manufacturing conditions for sample preparation, and the film thickness differs from the actual media structure because each sample is deposited with a film thickness suitable for measurement with a step gauge or ellipsometer. In this case, the film forming speed is calculated, and there is a problem that it involves an error.
[0008]
The present invention has been made to solve the above-mentioned conventional problems, and a multilayer thin film thickness measuring method capable of measuring the thickness of a plurality of thin film layers in a single measurement, and a method for measuring the film thickness. An object of the present invention is to provide an optical information recording medium manufacturing method and an optical information recording medium manufacturing apparatus in which a production loss due to creation of a film formation rate measurement sample is small and there is no need to temporarily change manufacturing conditions. To do.
[0009]
[Means for Solving the Problems]
To achieve the above object, a film thickness measurement method for a multilayer thin film of the present invention is composed of a plurality of different thin films their respective optical constants A film thickness measuring method of a multilayer thin film, the spectral reflectance of the multilayer film the wavelength at the maximum value of the measurement results was measured and compared with the standard values of the predetermined wavelength, based on the difference between the standard value of the wavelength wavelength at the maximum value of the measurement results, the multilayer film The thickness of the first thin film is obtained from the side of measuring the spectral reflectance of the multilayer thin film, and the reflectance difference between the maximum value and the minimum value of the measurement result obtained by measuring the spectral reflectance of the multilayer thin film is determined by a predetermined reflectance. Compared with the standard value of the difference, based on the difference between the reflectance difference between the local maximum value and the local minimum value of the measurement result and the standard value of the reflectance difference and the film thickness of the first thin film, Film thickness of the second thin film from the side where spectral reflectance is measured Seek.
Moreover, in the said method, it is preferable that the space | interval of each measurement wavelength at the time of measuring a spectral reflectance is 5 nm or less.
[0010]
On the other hand, the method for producing an optical information recording medium in the present invention is a method for producing an optical information recording medium having a multilayer thin film composed of a plurality of thin films each having a different optical constant, and the plurality of thin films are respectively formed on a substrate or a sample piece. A step of sequentially forming a film at a predetermined film formation speed and a film formation time, a step of measuring the spectral reflectance of the multilayer thin film on the substrate or the sample piece after the film formation, and a measurement result of measuring the spectral reflectance of the multilayer thin film The wavelength at the local maximum value is compared with a standard value of a predetermined wavelength, and the spectral reflectance of the multilayer thin film is measured based on the difference between the wavelength at the local maximum value of the measurement result and the standard value of the wavelength. The step of estimating the thickness of the first thin film from the side, and the deposition rate of the first thin film according to the difference between the estimated value of the thickness of the first thin film and the desired film thickness, and Deposition time The step of correcting at least one, and comparing the reflectance difference between the maximum value and the minimum value of the measurement result of measuring the spectral reflectance of the multilayer thin film with a standard value of the reflectance difference determined in advance, the measurement result From the side of measuring the spectral reflectance of the multilayer thin film based on the difference between the reflectance difference between the local maximum value and the local minimum value and the standard value of the reflectance difference and the estimated film thickness of the first thin film. A step of estimating the film thickness of the second thin film, and a film forming speed and a film forming time of the second thin film according to a difference between the estimated value of the film thickness of the second thin film and a desired film thickness A step of correcting at least one of the above, and a step of sequentially forming the plurality of thin films on a new substrate at respective corrected film formation speeds and film formation times.
[0011]
Another optical information recording medium manufacturing method according to the present invention is a method for manufacturing an optical information recording medium having a multilayer thin film composed of a plurality of thin films each having a different optical constant, and the plurality of thin films on a substrate or a sample piece. The step of sequentially forming a film at a predetermined film forming speed and time, the step of measuring the spectral reflectance of the multilayer thin film on the substrate or the sample piece after the film formation, and the spectral reflectance of the multilayer thin film were measured. The wavelength at the maximum value of the measurement result is compared with a standard value of a predetermined wavelength, and the spectral reflectance of the multilayer thin film is calculated based on the difference between the wavelength at the maximum value of the measurement result and the standard value of the wavelength. A multilayer formed on a substrate or a sample piece based on the difference between the step of estimating the thickness of the first thin film from the measuring side and the estimated thickness of the first thin film and the desired thickness The step of determining the quality of the film and selecting it, and comparing the reflectance difference between the maximum value and the minimum value of the measurement result of measuring the spectral reflectance of the multilayer thin film, with a predetermined standard value of the reflectance difference, The spectral reflectance of the multilayer thin film is measured based on the difference between the reflectance difference between the maximum and minimum values of the measurement result and the standard value of the reflectance difference and the estimated thickness of the first thin film. And the quality of the multilayer thin film formed on the substrate or the sample piece based on the difference between the estimated value of the thickness of the second thin film and the estimated thickness of the second thin film and the desired film thickness. And a step of selecting and sorting.
[0015]
In the above methods, it is preferable that the interval between the measurement wavelengths when measuring the spectral reflectance is 5 nm or less.
[0016]
The manufacturing apparatus of an optical information recording medium of the present invention is a manufacturing apparatus of an optical information recording medium having a multilayer thin film comprising a plurality of thin films having different their respective optical constants, the plurality of the piece substrate or sample measuring means for sequentially formed by a thin film of each predetermined deposition rate and deposition time, and means for measuring the spectral reflectance of the multilayer film on the strip substrate or sample after film formation, the spectral reflectance of the multilayer film the wavelength at the maximum value of the measurement results was, compared to a standard value of a predetermined wavelength, based on the difference between the standard value of the wavelength and the wavelength at the maximum value of the measurement results, the spectral reflection of the multilayer film Means for estimating the thickness of the first thin film from the rate measuring side, and the first thin film according to the difference between the estimated value of the thickness of the first thin film and the desired film thickness. Low film formation speed and film formation time Means for correcting one also, the reflectance difference between the maximum value and the minimum value of the spectral reflectance measurement result of measuring the multilayer film, as compared with the standard value of the reflectance difference predetermined for the measurement Based on the difference between the reflectivity difference between the maximum value and the minimum value and the standard value of the reflectivity difference and the estimated film thickness of the first thin film, the second from the side of measuring the spectral reflectivity of the multilayer thin film. Means for estimating the film thickness of the second thin film, and the film forming speed and film forming time of the second thin film according to the difference between the estimated value of the film thickness of the second thin film and the desired film thickness. Means for correcting at least one of them.
[0017]
Further, another optical information recording medium manufacturing apparatus of the present invention is an optical information recording medium manufacturing apparatus having a multilayer thin film composed of a plurality of thin films each having a different optical constant, and the plurality of thin films on a substrate or a sample piece. A means for sequentially forming a film at a predetermined film formation speed and a film formation time, a means for measuring the spectral reflectance of the multilayer thin film on the substrate or the sample piece after the film formation, and the spectral reflectance of the multilayer thin film were measured. The wavelength at the maximum value of the measurement result is compared with a standard value of a predetermined wavelength, and the spectral reflectance of the multilayer thin film is calculated based on the difference between the wavelength at the maximum value of the measurement result and the standard value of the wavelength. Multi-layer formed on the substrate or sample piece based on the difference between the means for estimating the film thickness of the first thin film from the measurement side and the estimated value of the film thickness of the first thin film and the desired film thickness Thin film Means for determining pass / fail and selecting the difference in reflectance between the maximum and minimum values of the measurement result obtained by measuring the spectral reflectance of the multilayer thin film is compared with a predetermined standard value of the difference in reflectance, and the measurement result From the side of measuring the spectral reflectance of the multilayer thin film based on the difference between the reflectance difference between the local maximum value and the local minimum value and the standard value of the reflectance difference and the estimated film thickness of the first thin film. The quality of the multilayer thin film formed on the substrate or the sample piece is determined based on the means for estimating the thickness of the second thin film and the difference between the estimated thickness of the second thin film and the desired film thickness. And sorting means.
[0020]
Moreover, in each said manufacturing apparatus, it is preferable that the space | interval of each measurement wavelength at the time of measuring a spectral reflectance is 5 nm or less.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0022]
The present invention focuses on the fact that the spectral reflectance characteristics change when the thickness of each layer of the multilayer thin film changes, and the wavelength and reflectance of the maximum and minimum points of the spectral reflectance correspond to the change of each thickness. Based on the characteristic change, the film thickness of the multilayer thin film is measured nondestructively.
[0023]
(First embodiment)
The first embodiment relates to a method for measuring a film thickness of a multilayer thin film and a method for manufacturing an optical information recording medium using the film thickness measuring method, and will be described with reference to FIGS.
[0024]
FIG. 1 is a flowchart showing the main part of the method for producing an optical information recording medium of the present invention. FIG. 2 is a cross-sectional view of the above-described general erasable optical information recording medium. FIG. 3 is a characteristic diagram showing an example of the measurement result of the spectral reflectance by the spectroscope of the optical information recording medium having the configuration shown in FIG.
[0025]
As shown in FIG. 1, first, the film formation time of each layer under a predetermined condition is set (S1). Next, the undercoat layer 3, the recording layer 4, the overcoat layer 5, and the reflective layer 6 are formed in this order on the transparent substrate 1 in accordance with the film formation time (S1 to S5). Thereafter, the spectral reflectance from the substrate side is measured with a spectroscope at a measurement wavelength range of 350 to 860 nm and a wavelength interval of 5 nm (S6). FIG. 3 shows the measurement results.
[0026]
Next, the maximum point and the minimum point of the obtained spectral reflectance are detected (S7, S13). The wavelength λ of the maximum point is measured (S8), compared with a predetermined standard value, and the difference Δλ is obtained (S9). In parallel with this, the reflectance Rmax at the local maximum point and the reflectance Rmin at the local minimum point are measured, and this reflectance difference Rmax−Rmin is compared with a predetermined standard value, and the difference Δ (Rmax−Rmin) is calculated. Obtain (S12, S14, S15, S16). Here, the standard value means the wavelength at the maximum point of the spectral reflectance and the difference in reflectance between the maximum point and the minimum point when each thin film layer is formed to have a film thickness as originally designed. These can be obtained experimentally or in advance.
[0027]
Next, the film thicknesses of the undercoat layer 3 and the recording layer 4 of the optical information recording medium 10 are calculated based on the measurement results (S10, S17). The calculation method is as follows.
[0028]
The difference x (%) from 100 nm, which is the standard value of the thickness of the undercoat layer 3, and the difference y (%) from 20 nm, which is the standard value of the film thickness of the recording layer, are expressed by the following equations (1), ( Calculate according to 2).
[0029]
[Expression 1]
Δλ = ax (1)
[0030]
[Expression 2]
Δ (Rmax−Rmin) = bx + cy (2)
When the undercoat layer 3 becomes thicker, λ shifts to the longer wavelength side, and when the undercoat layer 3 becomes thinner, it shifts to the shorter wavelength side. This is derived from the fact that λ is substantially constant even when the film thickness changes, and that Rmax−Rmin changes as the film thickness of the undercoat layer 3 and the recording layer 4 changes.
[0031]
However, constants a = 2.5, b = −0.22, and c = 0.34. Here, x and y are ratios with respect to the standard value of the difference from the standard value of each layer thickness. Each constant can be obtained from the spectral reflectance when the thickness of each layer is experimentally changed. Moreover, when the optical constant in each wavelength of each layer thin film is known, it can also obtain | require by calculating the reflectance by multiple interference. This constant varies depending on the standard value of each layer thickness.
[0032]
In accordance with the difference between the film thickness of each layer calculated as described above and its target value, the film formation time is changed so as to obtain a desired film thickness (S11, S18), and subsequent production is performed.
[0033]
As a result, it is not necessary to prepare a film formation rate measurement sample for each layer in the conventional example, and production loss can be reduced. In particular, the effect is remarkable when the film is formed by batch-type sputtering. In addition, it is not necessary to temporarily change the manufacturing conditions for sample preparation, and the time required for film formation speed measurement can be shortened by measuring the film thickness of two layers simultaneously, so the production line is operated more efficiently. be able to. Furthermore, since the film thickness can be measured with the actual structure of the medium, it is possible to determine whether the manufactured medium is good or not.
[0034]
(Second Embodiment)
The second embodiment relates to an apparatus for manufacturing an optical information recording medium using the method for measuring a film thickness of a multilayer thin film, and will be described with reference to FIGS.
[0035]
The optical information recording medium manufacturing apparatus 20 shown in FIG. 4 includes a substrate loading chamber 11, an undercoat layer deposition chamber 12, a recording layer deposition chamber 13, an upper coating layer deposition chamber 14, a reflective layer deposition chamber 15, and a substrate. The discharge chamber 16, the spectroscope 17, the arithmetic processing device 18, and the film formation condition control device 19 are configured.
[0036]
The operation of the optical information recording medium manufacturing apparatus configured as described above will be described. The transparent substrate 1 of the optical information recording medium 10 is loaded from the substrate loading chamber 11, and in the undercoat layer film forming chamber 12, the recording layer film forming chamber 13, the overcoat layer film forming chamber 14, and the reflective layer film forming chamber 15, respectively. An undercoat layer 3, a recording layer 4, an overcoat layer 5 and a reflective layer 6 are formed in sequence. Thereafter, the substrate 1 ′ on which the thin film of each layer is formed is taken out from the substrate discharge chamber 16. In each of the film forming chambers 12 to 15, the gas flow rate, pressure, power, and time are controlled to predetermined values by the film forming condition control device 19, and film forming is performed by sputtering under the conditions.
[0037]
The spectroscope 17 measures the spectral reflectance from the opposite side of the film-formed surface of the film-formed substrate 1 ′. The arithmetic processing unit 18 includes, for example, a CPU, a memory, etc., and compares the wavelength λ at the local maximum with a process for detecting the local maximum and local minimum of the spectral reflectance measured by the spectroscope 17 and a predetermined standard value. From the above-mentioned Δλ, a process for obtaining the difference Δλ, a process for comparing the difference Rmax−Rmin in reflectance between the maximum point and the minimum point with a predetermined standard value, and obtaining the difference Δ (Rmax−Rmin), From the process of calculating the difference between the film thickness of the undercoat layer 3 and the standard value of the optical information recording medium 10 by the predetermined formula, the Δ (Rmax−Rmin) and the film thickness of the undercoat layer 3 A process for calculating the difference between the film thickness of the recording layer 4 of the optical recording medium 10 and the standard value by a predetermined calculation formula, and the desired film thickness based on the difference between the film thickness of each layer and the standard value. When filming It has a process for calculating the changes the deposition time set in the film forming condition control device 19 based on the calculation result.
[0038]
According to this manufacturing apparatus, it is not necessary to create a film formation rate measurement sample for each layer, and production loss can be reduced. In particular, the effect is remarkable when film formation is performed by batch-type sputtering. In addition, there is no need to temporarily change the manufacturing conditions for sample preparation, and the time required for film formation speed measurement can be shortened by measuring the film thickness of two layers simultaneously, so that the production line is operated more efficiently. be able to. Furthermore, since the film thickness can be measured with the actual structure of the medium, it is possible to determine whether the manufactured medium is good or not.
[0039]
In the description of each of the above embodiments, the film formation time is changed in order to make the thin film of each layer a desired film thickness. However, the sputtering power, that is, the film formation speed may be changed. Further, instead of measuring the spectral reflectance of the optical information recording medium itself, the spectral reflectance of a sample formed on another substrate may be measured at the same time. The spectral reflectance measurement may be performed for every fixed number of manufactured sheets or for each sheet.
[0040]
In addition, when the spectral reflectance measurement wavelength interval is large, the film thickness measurement accuracy deteriorates. For example, in the case of the undercoat layer 3, a difference of λ of 10 nm corresponds to about 5% of the film thickness. Therefore, when the measurement accuracy of the required film thickness is 5%, it is preferable that the measurement wavelength interval is half that of 5 nm or less.
[0041]
Thus, the first method for producing an optical information recording medium in the present invention is a method for producing an optical information recording medium having a multilayer thin film comprising a plurality of thin films each having a different optical constant provided on a substrate, A step of sequentially forming the plurality of thin films on a substrate or a sample piece at a predetermined film formation rate and a film formation time; a step of measuring a spectral reflectance of a multilayer thin film on the substrate or the sample piece after the formation; The extreme value is detected from the measurement result of the spectral reflectance, and the thickness of the first thin film (undercoat layer) is estimated from the side where the spectral reflectance is measured based on the difference between the wavelength at the maximum value and the standard value. The spectral reflectance is calculated from the difference between the standard value of the reflectance difference between the maximum value and the minimum value of the spectral reflectance and the thickness of the first thin film (undercoat layer) from the side where the spectral reflectance is measured. 2nd thin from the measuring side The step of estimating the film thickness of the (recording layer) and the first and second thin films according to the difference between the estimated value of the film thickness of the first and second thin films and the desired film thickness A step of correcting at least one of the film forming speed and the film forming time, and a step of sequentially forming the plurality of thin films on the new substrate at the corrected film forming speed and film forming time, respectively. That is, by directly measuring the film thickness of the first film-formed substrate or the sample piece formed simultaneously with the substrate using the method for measuring the thickness of the multilayer thin film, the film thickness of a plurality of thin films can be measured in one measurement. The time required for film thickness measurement can be shortened, and the time required for film formation speed measurement can be shortened. In addition, since the film thickness can be measured with an actual medium structure, it is not necessary to temporarily change the manufacturing conditions for sample preparation. Therefore, the production line can be operated more efficiently, and production loss can be reduced. In particular, a remarkable effect is obtained when a film is formed by batch-type sputtering.
[0042]
The second method for producing an optical information recording medium in the present invention is a method for producing an optical information recording medium having a multilayer thin film comprising a plurality of thin films each having a different optical constant provided on a substrate, A step of sequentially depositing the plurality of thin films on the sample piece at a predetermined deposition rate and time, a step of measuring the spectral reflectance of the multilayer thin film on the substrate or the sample piece after the deposition, and the spectral reflection; Detecting the extreme value from the measurement result of the rate and estimating the film thickness of the first thin film (undercoat layer) from the side of measuring the spectral reflectance based on the difference between the wavelength at the maximum value and the standard value The spectral reflectance is measured from the difference between the maximum value of the spectral reflectance and the standard value of the difference in reflectance at the minimum value and the thickness of the first thin film (undercoat layer) from the side where the spectral reflectance is measured. The second thin film from the side Layer), and the quality of the multilayer thin film formed on the substrate is determined based on the difference between the estimated thickness of the first and second thin films and the desired film thickness. And sorting. Accordingly, since the film thickness of the actually manufactured optical information recording medium can be directly measured, it is possible to determine whether the manufactured optical information recording medium is good or not.
[0043]
On the other hand, a first manufacturing apparatus for an optical information recording medium according to the present invention is an apparatus for manufacturing an optical information recording medium having a multilayer thin film composed of a plurality of thin films each having a different optical constant provided on a substrate. Means for sequentially depositing the plurality of thin films on the sample piece respectively at a predetermined film forming speed and film forming time; means for measuring the spectral reflectance of the multilayer thin film on the substrate or the sample piece after film formation; and the spectral reflection Means for estimating the film thickness of the first thin film (undercoat layer) from the side of detecting the extreme value from the measurement result of the rate and measuring the spectral reflectance based on the difference between the wavelength at the maximum value and the standard value The spectral reflectance is measured from the difference between the maximum value of the spectral reflectance and the standard value of the difference in reflectance at the minimum value and the thickness of the first thin film (undercoat layer) from the side where the spectral reflectance is measured. The second thin film from the side The first and second thin films are formed according to the difference between the means for estimating the film thickness of the first layer and the second and the estimated values of the thicknesses of the first and second thin films and the desired film thickness. Means for correcting at least one of the film speed and the film formation time. That is, the film thickness measurement method of the multilayer thin film is used to measure the film thickness of the first film-formed substrate or the sample piece formed at the same time as the substrate, and according to the difference between the measured value and the standard value, By correcting at least one of the film formation time and the film formation speed, the film thickness of the thin film formed on the next substrate can be made closer to the design value. Furthermore, by repeating this step, the accuracy of the thickness of each thin film of the manufactured optical information recording medium can be further increased.
[0044]
Further, a second manufacturing apparatus for an optical information recording medium in the present invention is an apparatus for manufacturing an optical information recording medium having a multilayer thin film comprising a plurality of thin films each having a different optical constant provided on a substrate, Means for sequentially depositing the plurality of thin films on the sample piece respectively at a predetermined film forming speed and film forming time; means for measuring the spectral reflectance of the multilayer thin film on the substrate or the sample piece after film formation; and the spectral reflection Means for estimating the film thickness of the first thin film (undercoat layer) from the side of detecting the extreme value from the measurement result of the rate and measuring the spectral reflectance based on the difference between the wavelength at the maximum value and the standard value The spectral reflectance is measured from the difference between the maximum value of the spectral reflectance and the standard value of the difference in reflectance at the minimum value and the thickness of the first thin film (undercoat layer) from the side where the spectral reflectance is measured. The second thin film from the side And the quality of the multilayer thin film formed on the substrate based on the difference between the estimated value of the film thickness of the first and second thin films and the desired film thickness. And sorting means. Accordingly, since the film thickness of the actually manufactured optical information recording medium can be directly measured, it is possible to determine whether the manufactured optical information recording medium is good or not.
[0045]
Furthermore, in each manufacturing method and manufacturing apparatus of the optical information recording medium, the measurement accuracy of the film thickness is maintained at about 5% by setting the interval between the measurement wavelengths when measuring the spectral reflectance to 5 nm or less. Can do.
[0046]
【The invention's effect】
As described above, according to the method for measuring the thickness of an optical information recording medium of the present invention, the thickness of a plurality of thin films can be measured in one measurement, and the time required for measuring the thickness is shortened. be able to.
[0047]
Further, since the film thickness can be measured with the actual structure of the medium, it is not necessary to temporarily change the manufacturing conditions for sample preparation, and this is particularly effective when the film is formed by batch-type sputtering.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an essential part of an embodiment of a method for producing an optical information recording medium of the present invention. FIG. 2 is a cross-sectional view showing the structure of a general optical information recording medium. FIG. 4 is a characteristic diagram showing the relationship between spectral reflectance and wavelength. FIG. 4 is a block diagram showing the main part of an embodiment of the optical information recording medium manufacturing apparatus of the present invention.
DESCRIPTION OF SYMBOLS 1 Transparent substrate 1 'Transparent substrate in which the multilayer thin film was formed 2 Guide groove 3 Undercoat layer 4 Recording layer 5 Overcoat layer 6 Reflective layer 7 Resin protective layer 9 Center hole 10 Optical information recording medium 11 Substrate input chamber 12 Undercoat layer Deposition chamber 13 Recording layer deposition chamber 14 Overcoat layer deposition chamber 15 Reflective layer deposition chamber 16 Substrate discharge chamber 17 Spectrometer 18 Arithmetic processor 19 Deposition condition controller 20 Optical information recording medium manufacturing apparatus

Claims

Their respective A film thickness measuring method for a multilayer thin film comprising a plurality of different thin films optical constants, the wavelength at the maximum value of the measuring Teiyui results of the spectral reflectance was measured in the multilayer film, a predetermined compared to the standard value of the wavelength, on the basis of the difference between the standard value of the wavelength and the wavelength at the maximum value of the measurement results, the first th thickness of the thin film from the side of measuring the spectral reflectance of the multilayer film The difference between the maximum and minimum values of the measurement results obtained by measuring the spectral reflectance of the multilayer thin film is compared with a predetermined standard value of the difference in reflectance, and the maximum and minimum values of the measurement results are compared. Based on the difference between the reflectance difference and the standard value of the reflectance difference and the film thickness of the first thin film, the film thickness of the second thin film is obtained from the side of measuring the spectral reflectance of the multilayer thin film. A method for measuring the thickness of a multilayer thin film.

The method of measuring a film thickness of a multilayer thin film according to claim 1, wherein an interval between spectral reflectance measurement wavelengths is 5 nm or less.

The method for producing an optical information recording medium having a multilayer thin film comprising a plurality of different thin films their respective optical constants,
A step of sequentially depositing the plurality of thin films on a substrate or a sample piece respectively at a predetermined deposition rate and a deposition time;
Measuring the spectral reflectance of the multilayer thin film on the substrate or sample piece after film formation;
The wavelength at the maximum value of the measurement results of measurement of the spectral reflectance of the multilayer film, as compared with the standard value of the predetermined wavelength, the difference between the standard value of the wavelength and the wavelength at the maximum value of the measurement results Based on the step of estimating the thickness of the first thin film from the side of measuring the spectral reflectance of the multilayer thin film ,
Correcting at least one of a deposition rate and a deposition time of the first thin film according to a difference between an estimated value of the thickness of the first thin film and a desired film thickness ;
The reflectance difference between the maximum value and the minimum value of the measurement result obtained by measuring the spectral reflectance of the multilayer thin film is compared with a predetermined standard value of the difference in reflectance, and the reflectance between the maximum value and the minimum value of the measurement result is compared. Based on the difference between the difference and the standard value of the difference in reflectance and the estimated thickness of the first thin film, the thickness of the second thin film is estimated from the side of measuring the spectral reflectance of the multilayer thin film. And a process of
Correcting at least one of a deposition rate and a deposition time of the second thin film according to a difference between an estimated value of the thickness of the second thin film and a desired film thickness;
And a step of sequentially forming the plurality of thin films on a new substrate at respective corrected film formation speeds and film formation times.

The method for producing an optical information recording medium having a multilayer thin film comprising a plurality of different thin films their respective optical constants,
A step of sequentially depositing the plurality of thin films on a substrate or a sample piece respectively at a predetermined deposition rate and a deposition time;
Measuring the spectral reflectance of the multilayer thin film on the substrate or sample piece after film formation;
The wavelength at the maximum value of the measurement results of measurement of the spectral reflectance of the multilayer film, as compared with the standard value of the predetermined wavelength, the difference between the standard value of the wavelength and the wavelength at the maximum value of the measurement results Based on the step of estimating the thickness of the first thin film from the side of measuring the spectral reflectance of the multilayer thin film ,
A step of selecting and determining the quality of multi-layer thin film formed on a substrate or sample piece based on the difference of the estimated value of the film thickness of the first th thin film and a desired thickness,
The reflectance difference between the maximum value and the minimum value of the measurement result obtained by measuring the spectral reflectance of the multilayer thin film is compared with a predetermined standard value of the difference in reflectance, and the reflectance between the maximum value and the minimum value of the measurement result is compared. Based on the difference between the difference and the standard value of the difference in reflectance and the estimated thickness of the first thin film, the thickness of the second thin film is estimated from the side of measuring the spectral reflectance of the multilayer thin film. And a process of
And a step of selecting and determining the quality of multi-layer thin film formed on a piece of substrate or sample based on the difference of the estimated value of the film thickness of the first second thin film and the desired film thickness, the optical information recording medium Manufacturing method.

The method for producing an optical information recording medium according to claim 3 or 4 , wherein the spectral reflectance measurement wavelength interval is 5 nm or less.

A manufacturing apparatus of an optical information recording medium having a multilayer thin film comprising a plurality of different thin films their respective optical constants,
Means for sequentially depositing the plurality of thin films on a substrate or sample piece respectively at a predetermined deposition rate and deposition time;
Means for measuring the spectral reflectance of the multilayer thin film on the substrate or sample piece after film formation;
The wavelength at the maximum value of the measurement results of measurement of the spectral reflectance of the multilayer film, as compared with the standard value of the predetermined wavelength, the difference between the standard value of the wavelength and the wavelength at the maximum value of the measurement results Based on the means for estimating the film thickness of the first thin film from the side of measuring the spectral reflectance of the multilayer thin film ,
Means for correcting at least one of a deposition rate and a deposition time of the first thin film according to a difference between an estimated value of the thickness of the first thin film and a desired film thickness ;
The reflectance difference between the maximum value and the minimum value of the measurement result obtained by measuring the spectral reflectance of the multilayer thin film is compared with a predetermined standard value of the difference in reflectance, and the reflectance between the maximum value and the minimum value of the measurement result is compared. Based on the difference between the difference and the standard value of the difference in reflectance and the estimated thickness of the first thin film, the thickness of the second thin film is estimated from the side of measuring the spectral reflectance of the multilayer thin film. Means to
And means for correcting at least one of the deposition rate and the deposition time of the second-th thin film according to the difference of the estimated value of the film thickness of the first second thin film and the desired film thickness, the optical An apparatus for manufacturing an information recording medium.

A manufacturing apparatus of an optical information recording medium having a multilayer thin film comprising a plurality of different thin films their respective optical constants,
Means for sequentially depositing the plurality of thin films on a substrate or sample piece respectively at a predetermined deposition rate and deposition time;
Means for measuring the spectral reflectance of the multilayer film on the strip substrate or sample after film formation,
The wavelength at the maximum value of the measurement results of measurement of the spectral reflectance of the multilayer film, as compared with the standard value of the predetermined wavelength, the difference between the standard value of the wavelength and the wavelength at the maximum value of the measurement results Based on the means for estimating the film thickness of the first thin film from the side of measuring the spectral reflectance of the multilayer thin film ,
Means for selecting determines the quality of the multi-layer thin film formed on a substrate or sample piece based on the difference of the estimated value of the film thickness of the first th thin film and a desired thickness,
The reflectance difference between the maximum value and the minimum value of the measurement result obtained by measuring the spectral reflectance of the multilayer thin film is compared with a predetermined standard value of the difference in reflectance, and the reflectance between the maximum value and the minimum value of the measurement result is compared. Based on the difference between the difference and the standard value of the difference in reflectance and the estimated thickness of the first thin film, the thickness of the second thin film is estimated from the side of measuring the spectral reflectance of the multilayer thin film. Means to
An optical information recording medium comprising: means for determining whether or not a multilayer thin film formed on a substrate or a sample piece is good based on a difference between an estimated value of the thickness of the second thin film and a desired film thickness; Manufacturing equipment.

The apparatus for manufacturing an optical recording medium according to claim 6 or 7 , wherein an interval between spectral reflectance measurement wavelengths is 5 nm or less.