JP3869584B2

JP3869584B2 - Semiconductor device test element manufacturing method and thin film physical property value measuring method thereof

Info

Publication number: JP3869584B2
Application number: JP19992399A
Authority: JP
Inventors: 靖夫大曽根; 典生中里; 達也纐纈; 一男今井; 洋一玉置; 弘成松田
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1999-07-14
Filing date: 1999-07-14
Publication date: 2007-01-17
Anticipated expiration: 2019-07-14
Also published as: JP2001028385A

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体装置テストエレメントの製造方法及びその薄膜物性値測定方法に係わり、特にイオンスパッタリング等の手段により特定の原子を不純物として薄膜内に拡散させる半導体装置テストエレメントの製造方法及びその薄膜物性値測定方法に好適なものである。
【０００２】
【従来の技術】
半導体装置の熱的設計をする場合においては、発熱している接合部の温度を所定値以下に保ち、信頼性に優れた半導体装置を製造することが一つの目標となるが、そのために半導体装置の個々の構成材料の熱物性値及び部材界面における熱伝達率等を定量的に把握しようとすることが試みられている。半導体装置の発熱動作している領域の温度を直接測定することは困難であるため、接合部温度を予測するのに、数値シミュレーションを用いることが一般的に行われているが、従来は、個々の材料のバルクの物性値を薄膜材料に対しても用いることによって上記半導体装置の接合部温度を算出し、熱的設計の基準としている。
【０００３】
一方、代表的な熱物性値である熱拡散率については、交流加熱法を用いた薄膜材料の厚さ方向の熱拡散率の測定方法が特開平１０−３１８９５３号公報、特開平１０−２２１２７９号公報において開示されている。この従来技術は、熱拡散率を測定する薄膜を半導体装置とは全く別個に製作し、この薄膜の一方を電気的、もしくは光学的に周期加熱し、入射する熱の変動の位相と薄膜裏面側の温度の変動の位相との位相差から上記薄膜の膜厚方向の熱拡散率を測定するものである。特開平１０−３１８９５３号公報において開示された熱拡散率測定方法によれば導電性材料の熱拡散率を測定することが、また、特開平１０−２２１２７９号公報において開示された熱拡散率測定方法によれば複数層の薄膜の熱拡散率を測定することができる。上記測定方法により求めた膜厚方向の熱拡散率と、別途求めた比熱及び密度から薄膜材料の熱伝導率を算出する。
【０００４】
従来の半導体装置は、このような熱的設計に基いて、被測定薄膜の製造とは全く別個に独立して、ウエハ上に複数の薄膜を積層して半導体素子を形成することにより製造している。
【０００５】
【発明が解決しようとする課題】
現実の半導体装置の積層工程においては、例えばイオンスパッタリング等の手段により特定の原子を不純物として膜内に拡散させることにより、半導体装置としての特性を引き出すことが行われている。このため、半導体装置の個々の薄膜材料の物性値は上記不純物の拡散濃度や拡散範囲により強く影響を受ける。また、半導体装置の積層工程の温度や時間のばらつき、あるいは同一装置を製造する複数の製造装置間のばらつき等により、同じ製造方法の半導体装置であっても薄膜材料の物性値はばらつきを有する可能性がある。このため、半導体装置の熱的設計に必要な物性値は、標準的なサンプルの物性値ではなく、実際の半導体装置の構成材料となっている個々の薄膜材料そのものの物性値により近い値を測定することが必要である。特に、半導体装置においては、薄膜材料の厚さが非常に薄いことから、マクロスケールのサンプル材料と比較して、上述した不純物の拡散濃度等の条件による物性値の変動は極めて大きくなる。そこで、半導体装置の接合部温度の値をより実際に近いものに予測するために、材料物性値が実際の半導体装置の内部構造部材の物性値により近い物性値を測定することができる半導体装置テストエレメントの製造方法及びその薄膜物性値測定方法が望まれる。
【０００６】
本発明は、半導体装置の製造工程中に同一工程で被測定薄膜を製造することにより、被測定薄膜を製造する被測定薄膜の物性値を半導体素子の薄膜物性値に近いものとすることができ、信頼性に優れた半導体装置の熱的設計が可能な半導体装置テストエレメントの製造方法及びその薄膜物性値測定方法を得ることを目的とする。
【０００９】
【課題を解決するための手段】
本発明は、複数の薄膜を積層して半導体素子を形成するウエハ上に薄膜物性値を測定するためのテストエレメント領域を確保し、このテストエレメント領域に前記半導体素子を形成する絶縁性薄膜の形成工程と同一工程で絶縁性の被測定薄膜を形成し、かつ前記半導体素子を形成する導電性薄膜の形成工程と同一工程で加熱源用及び温度測定用の導電性薄膜を前記絶縁性の被測定薄膜の両側に形成して前記絶縁性の被測定薄膜に積層し、前記絶縁性の被測定薄膜及び加熱源用及び温度測定用の導電性薄膜の上に層間絶縁膜を積層させる構成にしたことにある。
【００１３】
また、本発明は、複数の薄膜を積層して半導体素子を形成するウエハ上に薄膜物性値を測定するためのテストエレメント領域を確保し、このテストエレメント領域に前記半導体素子を形成する絶縁性薄膜の形成工程と同一工程で絶縁性の被測定薄膜を形成し、かつ前記半導体素子を形成する導電性薄膜の形成工程と同一工程で加熱源用及び温度測定用の導電性薄膜を前記絶縁性の被測定薄膜の両側に形成して前記絶縁性の被測定薄膜に積層し、前記絶縁性の被測定薄膜及び加熱源用及び温度測定用の導電性薄膜の上に層間絶縁膜を積層させる工程と、前記加熱源用の導電性薄膜を通電加熱し、前記測定用の導電性薄膜の温度を測定することで熱物性値を測定する工程とを有する構成にしたことにある。
また、本発明は、複数の薄膜を積層して半導体素子を形成するウエハ上に薄膜物性値を測定するためのテストエレメント領域を確保し、このテストエレメント領域に前記半導体素子を形成する絶縁性薄膜の形成工程と同一工程で形成する絶縁性の被測定薄膜を形成し、かつ前記半導体素子を形成する導電性薄膜の形成工程と同一工程で加熱源用及び温度測定用の導電性薄膜を前記絶縁性の被測定薄膜の両側に形成して前記絶縁性の被測定薄膜に積層し、前記絶縁性の被測定薄膜及び加熱源用及び前記温度測定用の導電性薄膜は段差を有し、前記絶縁性の被測定薄膜及び加熱源用及び温度測定用の導電性薄膜の上に層間絶縁膜を積層させる構成にしたことにある。
また、本発明は、複数の薄膜を積層して半導体素子を形成するウエハ上に薄膜物性値を測定するためのテストエレメント領域を確保し、このテストエレメント領域の絶縁膜の切れ込みに、に前記半導体素子を形成する絶縁性薄膜の形成工程と同一工程で絶縁性の被測定薄膜を形成し、かつ前記半導体素子を形成する導電性薄膜の形成工程と同一工程で加熱源用及び温度測定用の導電性薄膜を前記絶縁性の被測定薄膜の両側に形成して前記絶縁性の被測定薄膜に積層し、前記絶縁性の被測定薄膜及び加熱源用及び前記温度測定用の導電性薄膜は前記絶縁膜の切れ込みによる段差を有し、前記絶縁性の被測定薄膜及び加熱源用及び温度測定用の導電性薄膜の上に層間絶縁膜を積層させる工程と、前記加熱源用の導電性薄膜を通電加熱し、前記測定用の導電性薄膜の温度を測定する工程とを有する構成にしたことにある。
【００１６】
【発明の実施の形態】
以下、本発明の導体装置用テストエレメントの製造方法が及びその薄膜物性値測定方法の各実施例を図を用いて説明する。なお、各実施例の共通または相当する部分の説明は省略すると共に、各実施例の図における同一符号は同一物または相当物を示す。
【００１７】
まず、本発明の第１実施例を図１及び図２を用いて説明する。図１は本発明の第１実施例における半導体ウェハ内に構成される薄膜物性値測定用テストエレメント領域の断面及び信号処理系を含む構成図、図２は本発明の各実施例における共通な半導体装置の平面図である。
【００１８】
図１に示す半導体装置は、代表的な一例として、シリコンウエハ上に絶縁膜であるＳｉＯ₂を載せたシリコンオンインシュレータウエハの場合を示すが、ウエハ上に半導体素子と同時にテストエレメント１７ａを積層できる構成であれば、ウエハの種類はシリコン単結晶に限らず、化合物半導体ウエハを含む全ての種類のウエハに適用可能である。シリコンウエハ１上にＳｉＯ２等の酸化膜２を積層させ、または両者を貼り合わせた基板の上のテストエレメント領域に、エピタキシャル成長層３、絶縁性の酸化膜４、５、６等を半導体装置の半導体素子のマスク工程順に積層する。図１の半導体装置の工程においては、熱物性値を測定する被測定薄膜７より先にポリシリコン等の導電性の薄膜を成膜する工程がある場合であり、テストエレメント１７ａは、この導電性薄膜８、被測定薄膜７を工程順に半導体素子と同一工程で積層し、更にその上に別の導電性の薄膜９を積層する。導電性の薄膜９については、配線層に用いられるタングステン、銅などの金属薄膜であってもよい。テストエレメント１７ａは、これらの薄膜８、７、９を順に積層した後、層間絶縁膜１０と配線層１１を積層し、最後にパッド電極１２を積層する。個々の導電性の薄膜８、９に対する配線１１はそれぞれ独立していなければならない。この第１実施例では導電性薄膜８を温度測定用薄膜として、導電性薄膜９を加熱源用薄膜として示すが、導電性薄膜８、９のうち、通電時の抵抗の温度特性が予め求められている方を温度測定用薄膜として、もう一方を加熱源用薄膜として使用することが良い。両方とも温度特性が判明している場合は、任意に加熱源用薄膜と温度測定用薄膜を定めることができる。
【００１９】
図１に示すように、加熱源である導電性薄膜９に交流電流発生装置１３を接続し、複数の加熱周波数を用いて被測定薄膜７を通電交流加熱する。被測定薄膜７に流入した熱は膜厚方向に伝播し、温度測定抵抗体薄膜側の面の温度も加熱周波数と同じ周波数で周期的に変動する。この変動の信号は、被測定薄膜７への入射熱の変動に対し一定の時間遅れを有し、変動の位相差は被測定薄膜７の熱拡散率と厚さに依存し、また、変動の振幅は被測定薄膜７の熱伝導率に依存する。従って、この位相差と、被測定薄膜７裏面の温度変動の振幅を温度測定用抵抗体である導電性薄膜８を用いて測定することにより、被測定薄膜７の熱拡散率と熱伝導率を求めることができる。具体的には、導電性薄膜８に直流電源１４により一定の微小電流を通電しておくことにより、被測定薄膜７裏面の温度が変動すると、導電性薄膜８の温度も同じ位相、振幅で変動し、その抵抗値が周期的に変動する。上記直流電源１４は常時一定電流を導電性薄膜８に供給するよう制御しておくことにより、温度に比例した電圧が導電性薄膜８にかかることになる。この電圧変動の信号をロックイン増幅器１５に取り込み、交流電流発生装置１３からの出力信号とロックインして両者の信号の位相差と、電圧変動の振幅を求め、コンピュータ等のデータ処理装置１６に電送する。このデータ処理装置１６により被測定薄膜７の熱拡散率と熱伝導率を算出する。
【００２０】
なお、図１において、絶縁膜４が中央部で切れ込み、絶縁性の酸化膜６、導電性薄膜８、被測定薄膜７、導電性薄膜９が下方に落ち込むような構造となっているが、実際の段差は無視できるほど小さい。また、エピタキシャル成長層３に特定の不純物を拡散させる必要がなく、被測定薄膜の物性に影響のない場合などには、テストエレメント１７ａにおいて絶縁性の酸化膜４の中央部の切れ込みは必要ない。図1における各種絶縁膜２、４、５、６、１０は、電気的な絶縁体としてのみならず、加熱源９から被測定薄膜７を経由して薄膜８に流れる熱の漏れを防ぐ断熱材として機能するので、実際の薄膜物性値により一層近い物性値を測定することができる。
【００２１】
図２に示すように、テストエレメント１７ａの領域は、このままの状態で製品である各半導体素子１８と全く同一のウエハ１上に確保されている。またテストエレメント１７ａは、図２の拡大図に示すように、テストエレメント１７ａを複数グループ化してテストエレメントグループ１７を形成しているので、図２の例においては、テストエレメント領域はテストエレメントグループ１７の領域を指すことになるが、テストエレメント１７ａがグループ化されずに単独で形成されている場合には、テストエレメント領域はテストエレメント１７ａの領域を指すことになる。このテストエレメントグループ１７の領域は、各半導体素子１８の領域と同じ大きさで隣接してその一つとみなされるように確保されているので、半導体素子１８の領域の一つをテストエレメントグループ１７の領域に割り当てることによりテストエレメントグループ１７の領域が確保でき、半導体装置用テストエレメントグループを容易に製造することができる。なお、図２には一つのテストエレメントグループ１７の領域にパッド電極１２を１２個ずつ持つテストエレメント１７ａが１６個並んで実装された例を示すが、このテストエレメント１７ａ当たりのパッド電極１２の数、テストエレメントグループ１７の領域内のテストエレメント１７ａの数や寸法も、図２の通りでなくても構わない。
【００２２】
上記半導体装置テストエレメントの製造方法及びその薄膜物性値測定方法においては、半導体素子１８を形成するウエハ１上に薄膜物性値を測定するためのテストエレメントグループ１７の領域を確保し、このテストエレメントグループ１７の領域に半導体素子１８を形成する薄膜の形成工程と同一工程で被測定薄膜７を形成することにより、半導体装置の半導体素子１８の製造工程を特に変更する必要がなく、半導体素子１８の薄膜に拡散されあるいは埋め込まれる各種不純物を被測定薄膜７も同様に吸収させることができ、被測定薄膜７の物性値を半導体素子１８の薄膜の物性値に近いものとすることができる。これにより信頼性に優れた半導体装置の熱的設計が可能な導体装置テストエレメントの製造方法が得られる。
【００２３】
また、電圧変動の振幅から被測定薄膜７の熱伝導率を算出することにより、容易に熱伝導率を測定することができる。
【００２４】
上記テストエレメント１７ａにおいては、ウエハ１上でプローブカード等によりパッド電極１２に直接通電して熱物性値を測定できる。なお、テストエレメントグループ１７の領域のみダイシング等により切り出して被測定薄膜７の熱物性値を求めても構わない。また、加熱源用薄膜９と温度測定抵抗体薄膜８への通電方法も、パッド電極１２経由でなくても良い。
【００２５】
なお、被測定薄膜７の熱伝導率については、被測定薄膜７のみ別途ガラス基板等の上に積層し、これから比熱と密度を求め、熱拡散率の測定結果と照らし合わせることによって算出してもよい。
【００２６】
さらに、テストエレメントグループ１７の領域は、複数箇所（この実施例においては４個所）確保しているので、図１の被測定薄膜７を測定するためのテストエレメントグループ１７の領域と、このテストエレメントグループ１７の領域に積層される温度測定用薄膜８に相当するものを被測定薄膜とするテストエレメントグループ１７の領域とを確保でき、図１の被測定薄膜７の物性値測定に必要な複数の薄膜を同一工程で製造することができることとなり、簡単で、より信頼性に優れた物性値の測定をすることができる半導体装置テストエレメントの製造方法が得られる。なお、テストエレメントグループ１７の領域の数やウエハ１上の配置は、図２の通りである必要はない。
【００２７】
次に、本発明の第２実施例を図３を用いて説明する。図３は本発明の第２実施例における半導体ウエハ内に構成される薄膜物性値測定用テストエレメント領域の断面及び信号処理系を含む構成図である。
【００２８】
この第２実施例のものにおいては、被測定薄膜７が導電性の薄膜である場合のものである。この被測定薄膜７が導電性の薄膜である場合には、第１実施例のように被測定薄膜７に加熱源用薄膜９と温度測定抵抗体薄膜８とを直接積層すると、加熱源用薄膜９と温度測定抵抗体薄膜８との間が短絡してしまい、熱物性値を測定することはできない。このため、導電性の薄膜の熱物性値を測定するためには、図３に示すように、加熱源である導電性薄膜９と被測定薄膜７との間、及び被測定薄膜７と温度測定用抵抗体である導電性薄膜８との間に、それぞれ絶縁性の薄膜１９、２０を積層し、薄膜７、１９、２０の多層薄膜の合成の熱物性値を測定する。薄膜１９、２０は絶縁膜であるから、予め図１の方法により薄膜１９、２０の熱物性値を測定しておくか、或いは他のテストエレメントグループ１７の領域でその薄膜を形成してその物性値を測定するようにすれば、被測定薄膜７の熱物性値を合成の熱物性値から算出できる。物性値を個々に測定すべき薄膜のためのテストエレメント１７ａを予めウエハ１上に組み込むことで、全く同じ工程を経た薄膜の物性値を測定でき、測定の精度を向上させることができる。また、薄膜１９、７、２０がこのままの順番で半導体素子１８内においても用いられている場合は、多層薄膜の合成の熱物性値を求め、一つの被測定薄膜として取り扱うことに実際の半導体装置により一層近い物性値を得ることができる。なお、この第２実施例のものにおいて、第１実施例と共通する構成においては同じ効果を奏するものである。
【００２９】
次に、本発明の第３実施例を図４及び図５を用いて説明する。図４は本発明の第３実施例におけるテストエレメント領域の製造工程を示す断面概略図、図５は図４で製造されたテストエレメント領域の断面及び信号処理系を含む構成図である。
【００３０】
この第３実施例のものは、被測定薄膜７を挟み込む形で複数の導電性薄膜８、９を積層できないような場合に適用するものである。例えば、図１または図３におけるエピタキシャル成長層３や絶縁性酸化膜２、４、６等を被測定薄膜としてその物性値を測定する場合であり、第３実施例として図４及び図５に示すものはエピタキシャル成長層３に被測定薄膜７を有するものである。このような場合は、まず、図４（ａ）に示すように、エピタキシャル成長層３に被測定薄膜７を有し、かつ絶縁性酸化膜６の上に導電性薄膜８及び被測定薄膜７を有しないテストエレメントを製造した後に、図４（ｂ）に示すように、ウエハ１の裏面側から研磨、エッチング等によりテストエレメント領域を薄層化する。次に、図４（ｃ）に示すように、アルミニウムや金等の金属薄膜２１を薄層化した面に積層する。なお、ウエハ表面側に加熱源用の導電性薄膜９は、半導体素子１８の製造工程と同一工程で積層しており、図５に示すように、この導電性薄膜９を用いて被測定薄膜７を交流通電加熱する。
【００３１】
一方、図５に示すように、光源２３から、ビームスプリッタ２４、１／４波長偏光板２５、光学顕微鏡２６を介して、一定出力のレーザ光２２を金属薄膜２１に照射し、金属薄膜２１裏面での反射光をフォトディテクタ２７で測定する。フォトディテクタ２７で測定される反射光の強度変動の大きさから金属薄膜２１裏面の温度を、反射光の位相と加熱源９へ供給される交流電流の位相との位相差から、上記第１及び第２実施例と同様に被測定薄膜７の熱物性値を測定することができる。照射レーザ光２２の波長が８１０ｎｍ前後の場合はアルミニウムを、６３０ｎｍ前後の場合は金を金属薄膜２１として積層することが望ましい。金属薄膜２１の厚さは、上記レーザ光２２に対して透明とならない程度以上の厚さであり、かつ、被測定薄膜７の厚さの１／１０以下であることが望ましいが、それ以外の厚さであっても、較正を十分行うことにより対応できる。一方、被測定薄膜７の面方向の寸法は、最低でも照射するレーザ光２２の直径以上、できれば１．５倍程度以上であることが望ましい。
【００３２】
上記各実施例においては、被測定薄膜を通過する熱の流れが膜厚方向のみであると考えてよい程度まで被測定薄膜７の膜厚の一辺長に対する比が小さいことが望ましく、この条件は第３実施例のレーザ光２２に対する寸法の条件に優先する。
【００３３】
【発明の効果】
本発明によれば、半導体装置の製造工程中に同一工程で被測定薄膜を製造することにより、被測定薄膜を製造する被測定薄膜の物性値を半導体素子の薄膜の物性値に近いものとすることができ、信頼性に優れた半導体装置の熱的設計が可能な半導体装置テストエレメントの製造方法及びその薄膜物性値測定方法を得ることができる。
【図面の簡単な説明】
【図１】発明の第１実施例における半導体ウエハ内に構成される薄膜物性値測定用テストエレメント領域の断面及び信号処理系を含む構成図である。
【図２】本発明の各実施例における共通な半導体装置の平面図である。
【図３】本発明の第２実施例における半導体ウエハ内に構成される薄膜物性値測定用テストエレメント領域の断面及び信号処理系を含む構成図である。
【図４】本発明の第３実施例におけるテストエレメント領域の製造工程を示す断面概略図である。
【図５】図４で製造されたテストエレメント領域の断面及び信号処理系を含む構成図である。
【符号の説明】
１…ウエハ、２…絶縁性酸化膜、３…エピタキシャル成長層、４、５、６…絶縁性酸化膜、７…被測定薄膜、８…導電性薄膜、９…導電性薄膜、１０…層間絶縁膜、１１…配線層、１２…パッド電極、１３…交流電流発生装置、１４…直流電源、１５…ロックイン増幅器、１６…データ処理装置、１７…テストエレメント、１８…半導体素子、１９…絶縁性薄膜、２０…絶縁性薄膜、２１…金属薄膜、２２…レーザ光、２３…レーザ光源、２４…ビームスプリッタ、２５…１／４波長偏光板、２６…光学顕微鏡、２７…フォトディテクタ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device test element and a method for measuring physical properties of the thin film, and more particularly to a method for manufacturing a semiconductor device test element in which specific atoms are diffused as impurities into the thin film by means such as ion sputtering and the thin film properties. It is suitable for a value measuring method.
[0002]
[Prior art]
In the case of thermal design of a semiconductor device, one of the goals is to manufacture a semiconductor device with excellent reliability by keeping the temperature of a junction that generates heat below a predetermined value. Attempts have been made to quantitatively grasp the thermophysical values of individual constituent materials and the heat transfer coefficient at the member interface. Since it is difficult to directly measure the temperature of the region where the semiconductor device generates heat, it is common to use numerical simulation to predict the junction temperature. The junction temperature of the semiconductor device is calculated by using the bulk physical property value of the material for the thin film material as a reference for the thermal design.
[0003]
On the other hand, as for the thermal diffusivity, which is a representative thermophysical value, a method for measuring the thermal diffusivity in the thickness direction of a thin film material using an AC heating method is disclosed in JP-A-10-318953 and JP-A-10-212279. It is disclosed in the publication. In this prior art, a thin film for measuring the thermal diffusivity is manufactured completely separately from the semiconductor device, one of the thin films is periodically heated electrically or optically, and the phase of the fluctuation of incident heat and the back side of the thin film The thermal diffusivity in the film thickness direction of the thin film is measured from the phase difference from the temperature fluctuation phase. According to the thermal diffusivity measuring method disclosed in Japanese Patent Laid-Open No. 10-318953, it is possible to measure the thermal diffusivity of a conductive material, and the thermal diffusivity measuring method disclosed in Japanese Patent Laid-Open No. 10-212279. Can measure the thermal diffusivity of a thin film of a plurality of layers. The thermal conductivity of the thin film material is calculated from the thermal diffusivity in the film thickness direction obtained by the above measurement method and the specific heat and density obtained separately.
[0004]
Conventional semiconductor devices are manufactured by laminating a plurality of thin films on a wafer to form a semiconductor element, independently of manufacturing a thin film to be measured, based on such a thermal design. Yes.
[0005]
[Problems to be solved by the invention]
In an actual semiconductor device stacking process, characteristics of the semiconductor device are extracted by diffusing specific atoms as impurities into the film by means such as ion sputtering. For this reason, the physical property value of each thin film material of the semiconductor device is strongly influenced by the diffusion concentration and diffusion range of the impurities. In addition, physical properties of thin film materials may vary even with semiconductor devices of the same manufacturing method due to temperature and time variations in the stacking process of semiconductor devices, or variations among multiple manufacturing devices that manufacture the same device. There is sex. For this reason, the physical property values required for the thermal design of semiconductor devices are not the physical property values of standard samples, but the values closer to the physical property values of the individual thin film materials themselves that are the constituent materials of actual semiconductor devices. It is necessary to. In particular, in a semiconductor device, since the thickness of the thin film material is very thin, the variation in the physical property value due to the above-described conditions such as the impurity diffusion concentration becomes extremely large as compared with the macroscale sample material. Therefore, in order to predict the junction temperature value of the semiconductor device closer to the actual one, the semiconductor device test that can measure the physical property value closer to the physical property value of the internal structure member of the actual semiconductor device An element manufacturing method and a thin film property value measuring method are desired.
[0006]
According to the present invention, by measuring the thin film to be measured in the same process during the manufacturing process of the semiconductor device, the physical property value of the thin film to be measured can be made close to the thin film physical property value of the semiconductor element. An object of the present invention is to obtain a method for manufacturing a semiconductor device test element and a method for measuring physical properties of the thin film, which enable thermal design of a semiconductor device having excellent reliability.
[0009]
[Means for Solving the Problems]
The present invention secures a test element region for measuring a physical property value of a thin film on a wafer on which a plurality of thin films are stacked to form a semiconductor element, and forms an insulating thin film for forming the semiconductor element in the test element region in the same process to form the measured thin film of insulating and the conductive thin film to be measured of the insulating heating source and for temperature measurement by forming the same process of the conductive thin film to form a semiconductor device It is formed on both sides of the thin film and laminated on the insulating thin film to be measured, and an interlayer insulating film is laminated on the insulating thin film to be measured and the conductive thin film for heating source and temperature measurement. It is in.
[0013]
Further, the present invention secures a test element region for measuring a thin film physical property value on a wafer on which a plurality of thin films are stacked to form a semiconductor element, and the insulating thin film forms the semiconductor element in the test element region The insulating thin film to be measured is formed in the same step as the forming step, and the conductive thin film for heating source and temperature measurement is formed in the same step as the conductive thin film forming step for forming the semiconductor element . a step of laminating the formed on both sides of the measured thin film laminated to the measured thin film of the insulating, the insulating interlayer insulating film on the conductive thin film and for the temperature measurement to be measured thin film and a heat source And a step of measuring a thermophysical value by energizing and heating the conductive thin film for the heating source and measuring the temperature of the conductive thin film for measurement.
Further, the present invention secures a test element region for measuring a thin film physical property value on a wafer on which a plurality of thin films are stacked to form a semiconductor element, and the insulating thin film forms the semiconductor element in the test element region An insulating thin film to be measured is formed in the same process as that for forming the conductive film, and the conductive thin film for heat source and temperature measurement is insulated in the same process as the conductive thin film forming process for forming the semiconductor element. sex and formed on both sides of the measured thin film laminated to the measured thin film of the insulating, the insulation of the conductive thin film for and the temperature measurement to be measured thin film and heat source has a step, the insulation In other words , an interlayer insulating film is laminated on the conductive thin film to be measured and the conductive thin film for heating source and temperature measurement.
Further, the present invention secures a test element region for measuring a thin film physical property value on a wafer on which a plurality of thin films are stacked to form a semiconductor element, and the semiconductor is cut into the insulating film in the test element region. The insulating thin film to be measured is formed in the same process as the insulating thin film forming process for forming the element, and the heat source and temperature measuring conductive process is performed in the same process as the conductive thin film forming process for forming the semiconductor element. An insulating thin film is formed on both sides of the insulating thin film to be measured, and is laminated on the insulating thin film. The insulating thin film, the heat source and the temperature measuring conductive thin film are insulated. It has a step due to cut the film, energizing a step of stacking an interlayer insulating film on the insulating conductive thin film and for the temperature measurement to be measured thin film and a heat source, a conductive thin film for the heat source Heat and measure In that a configuration and a step of measuring the temperature of the conductive thin film.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the method for producing a test element for a conductor device according to the present invention and the method for measuring thin film physical properties will be described below with reference to the drawings. In addition, while omitting the description of the common or corresponding parts of the embodiments, the same reference numerals in the drawings of the embodiments indicate the same or equivalent.
[0017]
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram including a cross section of a test element region for measuring thin film physical property values and a signal processing system formed in a semiconductor wafer in a first embodiment of the present invention, and FIG. 2 is a common semiconductor in each embodiment of the present invention. It is a top view of an apparatus.
[0018]
The semiconductor device shown in FIG. 1 shows a case of a silicon-on-insulator wafer in which SiO ₂ as an insulating film is placed on a silicon wafer as a representative example, but a test element 17a can be stacked on the wafer simultaneously with a semiconductor element. If it is a structure, the kind of wafer is applicable not only to a silicon single crystal but to all kinds of wafers including a compound semiconductor wafer. An epitaxial growth layer 3, insulating oxide films 4, 5, 6, etc. are formed on a test element region on a substrate on which an oxide film 2 such as SiO 2 is laminated or bonded together on a silicon wafer 1. The layers are stacked in the order of the mask process of the element. In the process of the semiconductor device of FIG. 1, there is a process of forming a conductive thin film such as polysilicon before the thin film to be measured 7 for measuring the thermophysical value. The thin film 8 and the thin film 7 to be measured are stacked in the same process as the semiconductor element in the order of processes, and another conductive thin film 9 is stacked thereon. The conductive thin film 9 may be a metal thin film such as tungsten or copper used for the wiring layer. In the test element 17 a, these thin films 8, 7, and 9 are sequentially stacked, the interlayer insulating film 10 and the wiring layer 11 are stacked, and finally the pad electrode 12 is stacked. The wirings 11 for the individual conductive thin films 8 and 9 must be independent from each other. In this first embodiment, the conductive thin film 8 is shown as a temperature measurement thin film and the conductive thin film 9 is shown as a heating source thin film. Of the conductive thin films 8 and 9, the temperature characteristics of the resistance during energization are obtained in advance. It is preferable to use the other as the temperature measurement thin film and the other as the heating source thin film. When the temperature characteristics of both are known, a heating source thin film and a temperature measurement thin film can be arbitrarily determined.
[0019]
As shown in FIG. 1, an alternating current generator 13 is connected to a conductive thin film 9 that is a heating source, and the thin film 7 to be measured is subjected to alternating current heating using a plurality of heating frequencies. The heat flowing into the thin film 7 to be measured propagates in the film thickness direction, and the temperature of the surface on the temperature measuring resistor thin film side also periodically varies at the same frequency as the heating frequency. The fluctuation signal has a certain time delay with respect to the fluctuation of the incident heat to the thin film 7 to be measured. The phase difference of the fluctuation depends on the thermal diffusivity and the thickness of the thin film 7 to be measured. The amplitude depends on the thermal conductivity of the thin film 7 to be measured. Therefore, by measuring the phase difference and the amplitude of the temperature fluctuation on the back surface of the thin film 7 to be measured using the conductive thin film 8 which is a temperature measuring resistor, the thermal diffusivity and the thermal conductivity of the thin film 7 to be measured are obtained. Can be sought. Specifically, when the temperature of the back surface of the thin film 7 to be measured is changed by passing a constant minute current from the DC power supply 14 to the conductive thin film 8, the temperature of the conductive thin film 8 also changes with the same phase and amplitude. However, the resistance value fluctuates periodically. The DC power supply 14 is controlled so as to always supply a constant current to the conductive thin film 8, whereby a voltage proportional to the temperature is applied to the conductive thin film 8. This voltage fluctuation signal is taken into the lock-in amplifier 15 and locked in with the output signal from the alternating current generator 13 to obtain the phase difference between the two signals and the amplitude of the voltage fluctuation. Send by electricity. The data processor 16 calculates the thermal diffusivity and thermal conductivity of the thin film 7 to be measured.
[0020]
In FIG. 1, the insulating film 4 is cut at the center, and the insulating oxide film 6, the conductive thin film 8 , the thin film 7 to be measured, and the conductive thin film 9 are lowered downward. The level difference is negligibly small. Further, when there is no need to diffuse a specific impurity in the epitaxial growth layer 3 and the physical properties of the thin film to be measured are not affected, it is not necessary to cut the central portion of the insulating oxide film 4 in the test element 17a. The various insulating films 2, 4, 5, 6, and 10 in FIG. 1 are not only electrical insulators but also heat insulating materials that prevent leakage of heat flowing from the heating source 9 to the thin film 8 via the thin film 7 to be measured. Therefore, the physical property value closer to the actual thin film physical property value can be measured.
[0021]
As shown in FIG. 2, the region of the test element 17a is secured on the same wafer 1 as each product semiconductor element 18 in this state. Further, as shown in the enlarged view of FIG. 2, the test element 17a is formed by grouping a plurality of test elements 17a to form the test element group 17. Therefore, in the example of FIG. When the test element 17a is formed independently without being grouped, the test element area indicates the area of the test element 17a. Since the area of the test element group 17 has the same size as the area of each semiconductor element 18 and is secured so as to be regarded as one of the areas, one of the areas of the semiconductor element 18 is defined as the area of the test element group 17. By allocating to the area, the area of the test element group 17 can be secured, and the test element group for a semiconductor device can be easily manufactured. FIG. 2 shows an example in which 16 test elements 17a each having 12 pad electrodes 12 are mounted side by side in the area of one test element group 17. The number of pad electrodes 12 per test element 17a is shown in FIG. The number and dimensions of the test elements 17a in the region of the test element group 17 may not be as shown in FIG.
[0022]
In the semiconductor device test element manufacturing method and the thin film physical property value measuring method, an area of the test element group 17 for measuring the thin film physical property value is secured on the wafer 1 on which the semiconductor element 18 is formed. By forming the thin film to be measured 7 in the same process as the thin film forming process for forming the semiconductor element 18 in the region 17, there is no need to change the manufacturing process of the semiconductor element 18 of the semiconductor device. Various impurities diffused or embedded in the thin film 7 to be measured can be similarly absorbed, and the physical property value of the thin film 7 to be measured can be close to the physical property value of the thin film of the semiconductor element 18. As a result, a method of manufacturing a conductor device test element capable of thermally designing a semiconductor device having excellent reliability can be obtained.
[0023]
Further, the thermal conductivity can be easily measured by calculating the thermal conductivity of the thin film 7 to be measured from the amplitude of the voltage fluctuation.
[0024]
In the test element 17a, a thermal property value can be measured by directly energizing the pad electrode 12 with a probe card or the like on the wafer 1. Note that only the region of the test element group 17 may be cut out by dicing or the like to obtain the thermal property value of the thin film 7 to be measured. Also, the method of energizing the heating source thin film 9 and the temperature measuring resistor thin film 8 may not be via the pad electrode 12.
[0025]
Note that the thermal conductivity of the thin film 7 to be measured may be calculated by laminating only the thin film 7 to be measured on a glass substrate or the like, obtaining the specific heat and density from this, and comparing it with the measurement result of the thermal diffusivity. Good.
[0026]
Further, since a plurality of test element group 17 regions (four in this embodiment) are secured, the test element group 17 region for measuring the thin film 7 to be measured shown in FIG. 1 can be secured, and a plurality of regions necessary for measuring physical properties of the thin film 7 to be measured in FIG. 1 can be secured. Since the thin film can be manufactured in the same process, a method of manufacturing a semiconductor device test element that can measure physical property values that are simpler and more reliable can be obtained. The number of test element group 17 areas and the arrangement on the wafer 1 do not have to be as shown in FIG.
[0027]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram including a cross section of a thin film physical property value measurement test element region formed in a semiconductor wafer and a signal processing system in a second embodiment of the present invention.
[0028]
In the second embodiment, the thin film 7 to be measured is a conductive thin film. When the thin film to be measured 7 is a conductive thin film, the thin film for heating source is obtained by directly laminating the thin film for heating source 9 and the thin film for temperature measuring resistor 8 on the thin film to be measured 7 as in the first embodiment. 9 and the temperature measuring resistor thin film 8 are short-circuited, and the thermophysical property value cannot be measured. Therefore, in order to measure the thermophysical value of the conductive thin film, as shown in FIG. 3, between the conductive thin film 9 as a heating source and the thin film 7 to be measured and between the thin film 7 to be measured and the temperature measurement. Insulating thin films 19 and 20 are laminated between the conductive thin film 8 and the conductive thin film 8, respectively, and the thermal properties of the multilayer thin films 7, 19 and 20 are measured. Since the thin films 19 and 20 are insulating films, the thermophysical values of the thin films 19 and 20 are measured in advance by the method of FIG. 1, or the thin film is formed in the region of another test element group 17 and the physical properties thereof. If the value is measured, the thermophysical value of the thin film 7 to be measured can be calculated from the synthesized thermophysical value. By incorporating the test element 17a for the thin film whose physical property values are to be individually measured on the wafer 1, the physical property value of the thin film that has undergone exactly the same process can be measured, and the measurement accuracy can be improved. Further, when the thin films 19, 7, and 20 are also used in the semiconductor element 18 in this order, the actual semiconductor device is obtained by obtaining the thermophysical value of the synthesis of the multilayer thin film and handling it as one thin film to be measured. Therefore, it is possible to obtain closer physical property values. In the second embodiment, the same effects as those in the first embodiment can be obtained.
[0029]
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a schematic cross-sectional view showing the manufacturing process of the test element region in the third embodiment of the present invention, and FIG. 5 is a block diagram including the cross-section of the test element region manufactured in FIG. 4 and a signal processing system.
[0030]
The third embodiment is applied to a case where a plurality of conductive thin films 8 and 9 cannot be stacked with the thin film 7 to be measured interposed therebetween. For example, the physical property value is measured using the epitaxially grown layer 3 or the insulating oxide films 2, 4, 6, etc. in FIG. 1 or FIG. 3 as a thin film to be measured. The third embodiment is shown in FIGS. 4 and 5. Has the thin film 7 to be measured in the epitaxial growth layer 3. In such a case, first, as shown in FIG. 4A, the epitaxially grown layer 3 has the measured thin film 7, and the insulating thin film 6 has the conductive thin film 8 and the measured thin film 7. After the test element to be manufactured is manufactured, as shown in FIG. 4B, the test element region is thinned by polishing, etching, or the like from the back side of the wafer 1. Next, as shown in FIG. 4C, a metal thin film 21 such as aluminum or gold is laminated on the thinned surface. In addition, the conductive thin film 9 for the heat source is laminated on the wafer surface side in the same process as the manufacturing process of the semiconductor element 18, and as shown in FIG. Is heated by alternating current.
[0031]
On the other hand, as shown in FIG. 5, a laser beam 22 having a constant output is irradiated onto the metal thin film 21 from the light source 23 via the beam splitter 24, the quarter wavelength polarizing plate 25, and the optical microscope 26. The reflected light at is measured with a photodetector 27. The temperature of the back surface of the metal thin film 21 is determined from the magnitude of the intensity fluctuation of the reflected light measured by the photodetector 27, and the first and second phases are determined from the phase difference between the phase of the reflected light and the phase of the alternating current supplied to the heating source 9. The thermophysical property value of the thin film 7 to be measured can be measured as in the second embodiment. It is desirable to laminate aluminum as the metal thin film 21 when the wavelength of the irradiation laser beam 22 is around 810 nm and when it is around 630 nm. It is desirable that the thickness of the metal thin film 21 is not less than the thickness of the laser beam 22 and not more than 1/10 of the thickness of the thin film 7 to be measured. Even the thickness can be accommodated by sufficient calibration. On the other hand, the dimension in the plane direction of the thin film 7 to be measured is desirably at least the diameter of the laser beam 22 to be irradiated, preferably about 1.5 times or more if possible.
[0032]
In each of the above embodiments, it is desirable that the ratio of the film thickness of the thin film to be measured 7 to the length of one side is small to the extent that the heat flow passing through the thin film to be measured can be considered only in the film thickness direction. This takes precedence over the dimensional condition for the laser beam 22 of the third embodiment.
[0033]
【The invention's effect】
According to the present invention, by manufacturing the thin film to be measured in the same process during the manufacturing process of the semiconductor device, the physical property value of the thin film to be measured for manufacturing the thin film to be measured is close to the physical property value of the thin film of the semiconductor element. Therefore, it is possible to obtain a method for manufacturing a semiconductor device test element and a method for measuring physical properties of the thin film, which enable thermal design of a semiconductor device having excellent reliability.
[Brief description of the drawings]
FIG. 1 is a configuration diagram including a cross section of a thin film property value measurement test element region formed in a semiconductor wafer and a signal processing system in a first embodiment of the invention.
FIG. 2 is a plan view of a common semiconductor device in each embodiment of the present invention.
FIG. 3 is a block diagram including a cross section of a thin film property value measurement test element region configured in a semiconductor wafer and a signal processing system in a second embodiment of the present invention;
FIG. 4 is a schematic cross-sectional view showing a manufacturing process of a test element region in a third embodiment of the present invention.
5 is a configuration diagram including a cross section of a test element region manufactured in FIG. 4 and a signal processing system. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Insulating oxide film, 3 ... Epitaxial growth layer, 4, 5, 6 ... Insulating oxide film, 7 ... Thin film to be measured, 8 ... Conductive thin film, 9 ... Conductive thin film, 10 ... Interlayer insulating film DESCRIPTION OF SYMBOLS 11 ... Wiring layer, 12 ... Pad electrode, 13 ... AC current generator, 14 ... DC power supply, 15 ... Lock-in amplifier, 16 ... Data processing device, 17 ... Test element, 18 ... Semiconductor element, 19 ... Insulating thin film 20 ... Insulating thin film, 21 ... Metal thin film, 22 ... Laser light, 23 ... Laser light source, 24 ... Beam splitter, 25 ... 1/4 wavelength polarizing plate, 26 ... Optical microscope, 27 ... Photo detector.

Claims

The same process as the process of forming an insulating thin film for securing a test element region for measuring thin film physical properties on a wafer on which a plurality of thin films are stacked to form a semiconductor element and forming the semiconductor element in the test element region And forming a conductive thin film for heating source and temperature measurement on both sides of the thin film to be measured in the same process as the conductive thin film forming process for forming the semiconductor element. A semiconductor device test comprising: forming and laminating the insulating thin film to be measured; and laminating an interlayer insulating film on the insulating thin film to be measured and the conductive thin film for heating source and temperature measurement Element manufacturing method.

The same process as the process of forming an insulating thin film for securing a test element region for measuring thin film physical properties on a wafer on which a plurality of thin films are stacked to form a semiconductor element and forming the semiconductor element in the test element region And forming a conductive thin film for heating source and temperature measurement on both sides of the thin film to be measured in the same process as the conductive thin film forming process for forming the semiconductor element. Forming and laminating the insulating thin film to be measured, and laminating an interlayer insulating film on the insulating thin film to be measured and the conductive thin film for heat source and temperature measurement;
A method for measuring a thin film physical property value of a semiconductor test element, comprising: a step of energizing and heating the conductive thin film for the heating source, and measuring a thermophysical property value by measuring a temperature of the conductive thin film for measurement.

The same process as the process of forming an insulating thin film for securing a test element region for measuring thin film physical properties on a wafer on which a plurality of thin films are stacked to form a semiconductor element and forming the semiconductor element in the test element region in the measured film insulative forming to form, and the conductive thin film said insulating measured films for heat source and for temperature measurement in the same step as the step forming the conductive thin film to form a semiconductor device formed on both sides is laminated to the measured thin film of the insulating, the insulation of the conductive thin film for and the temperature measurement to be measured thin film and heat source has a step, the insulating of the measured thin film and A method for manufacturing a semiconductor device test element, comprising: laminating an interlayer insulating film on a conductive thin film for heating source and temperature measurement.

A test element region for measuring physical property values of a thin film is secured on a wafer on which a plurality of thin films are stacked to form a semiconductor element, and the insulating property for forming the semiconductor element in the cut of the insulating film in the test element region The insulating thin film to be measured is formed in the same process as the thin film forming process, and the conductive thin film for heating source and temperature measurement is formed in the same process as the conductive thin film forming process for forming the semiconductor element . of and on both sides of the measured thin film laminated to the measured thin film of the insulating, the insulation of the conductive thin film for and the temperature measurement to be measured thin film and heat source the step due to cuts of the insulating film a, a step of stacking an interlayer insulating film on the insulating conductive thin film and for the temperature measurement to be measured thin film and heating source,
A method for measuring a physical property of a thin film of a semiconductor test element, comprising a step of energizing and heating the conductive thin film for the heating source and measuring the temperature of the conductive thin film for measurement.