JPH0618430A - Surface inspection method for wafer with film - Google Patents
Surface inspection method for wafer with filmInfo
- Publication number
- JPH0618430A JPH0618430A JP4176596A JP17659692A JPH0618430A JP H0618430 A JPH0618430 A JP H0618430A JP 4176596 A JP4176596 A JP 4176596A JP 17659692 A JP17659692 A JP 17659692A JP H0618430 A JPH0618430 A JP H0618430A
- Authority
- JP
- Japan
- Prior art keywords
- wafer
- film
- laser
- foreign matter
- surface roughness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、蒸着膜(以下単に膜と
言う)が蒸着された膜付きウェーハの表面に付着した異
物などの欠陥を検出する検査方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method for detecting defects such as foreign substances attached to the surface of a film-coated wafer on which a vapor-deposited film (hereinafter simply referred to as a film) is deposited.
【0002】[0002]
【従来の技術】半導体ICの製造工程において、シリコ
ンウェーハの表面にCVD装置による多結晶ポリシリコ
ン膜や、スパッタ装置によるアルミ膜などを蒸着する工
程でウェーハに付着する異物は、製品の歩留を低下させ
る主要な原因となる。2. Description of the Related Art In the process of manufacturing a semiconductor IC, foreign matter adhering to a wafer in the process of depositing a polycrystalline polysilicon film by a CVD device or an aluminum film by a sputtering device on the surface of a silicon wafer will reduce the product yield. It is the main cause of decrease.
【0003】従来においては、膜付きウェーハに対する
適切な表面検査方法がなく、膜が蒸着される前の、いわ
ゆる鏡面ウェーハに対する表面検査方法を、膜付きウェ
ーハの表面検査に適用していた。Conventionally, there is no suitable surface inspection method for a film-coated wafer, and a so-called mirror surface wafer surface inspection method before film deposition is applied to the film-coated wafer surface inspection.
【0004】以下、図面を参照しながら、上記した従来
のウェーハ表面検査装置の一例について説明する。An example of the conventional wafer surface inspection apparatus described above will be described below with reference to the drawings.
【0005】図6は従来のウェーハ表面検査装置の検出
光学系を示すものである。図6において、1は入射レー
ザービーム、2は投光レンズ、4aは鏡面ウェーハ、5
は回転ステージ、6はオプティカルファイバーである。FIG. 6 shows a detection optical system of a conventional wafer surface inspection apparatus. In FIG. 6, 1 is an incident laser beam, 2 is a projection lens, 4a is a mirror surface wafer, 5
Is a rotary stage, and 6 is an optical fiber.
【0006】以上のように構成されたウェーハ表面検査
装置について、以下その動作について説明する。The operation of the wafer surface inspecting apparatus constructed as above will be described below.
【0007】まず、入射されたレーザー光1は、投光レ
ンズ2により、ウェーハ表面で10〜100μm程度のスポ
ットに集光される。ウェーハ表面に異物3aが存在して
いる場合、異物からの微弱な散乱光を、多数の光ファイ
バー6が集光し、光電素子で電気信号に変換することに
より異物を検出する。(例えば、「月刊Semiconductor
Worl」(1992.4)116〜121ページ)。First, the incident laser beam 1 is condensed by the light projecting lens 2 into a spot of about 10 to 100 μm on the wafer surface. When the foreign matter 3a is present on the surface of the wafer, the weak scattered light from the foreign matter is collected by a large number of optical fibers 6 and is converted into an electric signal by a photoelectric element to detect the foreign matter. (For example, "Monthly Semiconductor
Worl "(1992.4) pp. 116-121.
【0008】[0008]
【発明が解決しようとする課題】しかしながら上記のよ
うな構成の鏡面ウェーハに対する欠陥検出光学系は、異
物からの十分な散乱光強度を得るために、レーザーの入
射角度はウェーハに対して垂直に近い。したがって、膜
付きウェーハの表面検査に適応する場合、膜に含まれる
結晶微粒子によるレーザー散乱や、膜の厚さの不均一性
によるレーザー干渉レベルの変化によって、結晶微粒子
の誤検出や検出感度にムラが発生し、高感度な膜付きウ
ェーハの欠陥検査を行なうことができないという問題点
を有していた。However, in the defect detection optical system for the mirror-finished wafer having the above-mentioned structure, the incident angle of the laser is almost perpendicular to the wafer in order to obtain sufficient scattered light intensity from the foreign matter. . Therefore, when it is applied to the surface inspection of a film-coated wafer, erroneous detection of crystal particles and uneven detection sensitivity may occur due to laser scattering due to the crystal particles contained in the film and changes in the laser interference level due to non-uniformity of the film thickness. Therefore, there is a problem in that it is not possible to perform a defect inspection of a highly sensitive film-coated wafer.
【0009】本発明は上記問題点に鑑み表面荒れや膜厚
ムラを有した膜付きウェーハの高感度な表面検査方法を
提供するものである。In view of the above problems, the present invention provides a highly sensitive surface inspection method for a film-coated wafer having surface roughness and film thickness unevenness.
【0010】[0010]
【課題を解決するための手段】上記問題点を解決するた
めに本発明の膜付きウェーハの表面検査方法は、レーザ
ー入射角度がウェーハに対して鋭角の光学系を用いたも
のである。In order to solve the above problems, the surface inspection method for a film-coated wafer of the present invention uses an optical system in which the laser incident angle is an acute angle with respect to the wafer.
【0011】[0011]
【作用】本発明は上記した構成によって、蒸着膜4bの
表面荒れに対するレーザー散乱断面積を減少させ、かつ
異物3aからの後方散乱光や蒸着膜4bの表面や界面で
反射した前方散乱光が成分間で起こすレーザー干渉を減
少させることにより、表面荒れや膜厚ムラを有した膜付
きウェーハの表面検査を高感度で行なうことができるの
である。The present invention has the above-described structure to reduce the laser scattering cross-sectional area against the surface roughness of the vapor deposition film 4b, and the backscattered light from the foreign matter 3a and the forward scattered light reflected on the surface or interface of the vapor deposition film 4b are components. By reducing the laser interference that occurs between the surfaces, the surface inspection of the film-coated wafer having surface roughness and film thickness unevenness can be performed with high sensitivity.
【0012】[0012]
【実施例】以下本発明の一実施例の膜付きウェーハの表
面検査方法について、図面を参照しながら説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for inspecting a surface of a film-coated wafer according to an embodiment of the present invention will be described below with reference to the drawings.
【0013】図1は本発明の実施例における膜付きウェ
ーハの表面検査方法の光学系の説明図である。図1にお
いて、1は入射レーザー、2は投光レンズ、4aはウェ
ーハ、4bは蒸着膜、5は回転テーブル、6はオプティ
カルファイバーである 以上のように構成された膜付き
ウェーハの表面検査方法について、以下図2及び図3を
用いてその動作を説明する。FIG. 1 is an explanatory diagram of an optical system of a method for inspecting a surface of a film-coated wafer according to an embodiment of the present invention. In FIG. 1, 1 is an incident laser, 2 is a projection lens, 4a is a wafer, 4b is a vapor deposition film, 5 is a rotary table, and 6 is an optical fiber. The surface inspection method for a film-coated wafer constructed as described above The operation will be described below with reference to FIGS. 2 and 3.
【0014】まず図2a及び図2bは、それぞれ、従来
例と本実施例における異物による散乱光の各成分の干渉
を示すものである。図2aに示す従来例では、異物3a
による後方散乱光7a、異物表面で反射した前方散乱光
7b、ウェーハ4aとウェーハ4bとの界面で反射した
前方散乱光7cの各成分の中心方向が同一であるため、
膜厚により位相にずれが生じる界面で反射した前方散乱
光7cが他の成分と干渉を起こし、ウェーハ面内に膜厚
ムラを有する場合、面内での感度にムラが生じた。一
方、図2(b)に示す本実施例では、各散乱光成分の中
心方向または中心位置が異なるため、各散乱光成分間の
レーザー干渉は低減され、ウェーハ面内で安定した感度
が得られる。First, FIGS. 2a and 2b show the interference of each component of the scattered light by the foreign matter in the conventional example and the present example, respectively. In the conventional example shown in FIG. 2a, the foreign matter 3a
Since the backscattered light 7a, the forward scattered light 7b reflected on the surface of the foreign matter, and the forward scattered light 7c reflected at the interface between the wafer 4a and the wafer 4b have the same central direction,
When the forward scattered light 7c reflected at the interface where the phase shifts due to the film thickness interferes with other components, and the film thickness is uneven within the wafer surface, the in-plane sensitivity is uneven. On the other hand, in the present embodiment shown in FIG. 2B, since the center direction or center position of each scattered light component is different, laser interference between each scattered light component is reduced, and stable sensitivity is obtained within the wafer surface. .
【0015】次に図3a及び図3bは、それぞれ、従来
例と本実施例における表面荒れによるノイズ成分を示す
ものである。図3(a)の従来例では、異物3aと表面
荒れ3bが、入射レーザーに対して同等の散乱面積を持
つが、図3(b)の本実施例では、表面荒れ3bのみの
散乱断面積が減少し、異物3aのみを高感度に検出する
ことができる。Next, FIGS. 3a and 3b show noise components due to surface roughness in the conventional example and the present example, respectively. In the conventional example of FIG. 3 (a), the foreign matter 3a and the surface roughness 3b have the same scattering area with respect to the incident laser, but in the present embodiment of FIG. 3 (b), the scattering cross-sectional area of only the surface roughness 3b. Is reduced, and only the foreign matter 3a can be detected with high sensitivity.
【0016】更に、その効果について図4及び図5を用
いて説明する。図4及び図5は、それぞれ、膜厚ムラ及
び表面荒れを有したウェーハの、OF(オリエンテーシ
ョンフラット)を下にして左半面の表面に0.5μmのP
SL標準粒子を均一に付着した試料について、従来例図
4a、図5aと本実施例図4b、図5bの表面検査方法
で測定した結果である。Further, the effect will be described with reference to FIGS. 4 and 5. FIGS. 4 and 5 show a wafer having unevenness in film thickness and surface roughness, with 0.5 μm P on the left half surface with the OF (orientation flat) facing down.
It is the result of having measured by the surface inspection method of the conventional example FIGS. 4a and 5a and this Example FIG. 4b and FIG.
【0017】まず図4aでは、ウェーハの上下方向に膜
厚ムラが有り、左半面の表面に0.5μmのPSL標準粒
子を均一に付着した試料であるにもかかわらず、OFを
下にして上部左半面の検出感度が低下している。一方、
図4bではウェーハの左半面に均一な検出感度が得られ
ている。First, in FIG. 4a, although the film thickness is uneven in the vertical direction of the wafer and the PSL standard particles of 0.5 μm are evenly adhered to the surface of the left half surface, the OF is turned down and the upper left is turned on. The detection sensitivity on one side is reduced. on the other hand,
In FIG. 4b, a uniform detection sensitivity is obtained on the left half surface of the wafer.
【0018】次に、図5aでは、ウェーハ全面に表面荒
れが有り、0.5μmのPSL標準粒子は、OFを下にし
て左半面にのみ付着しているのにも関わらず、右半面に
も表面荒れによる誤検出が認められる。一方、図5bで
はウェーハの右半面に誤検出はなく、左半面のみに均一
な検出感度が得られている。Next, in FIG. 5a, there is surface roughness on the entire surface of the wafer, and the PSL standard particles of 0.5 μm adhere to only the left half surface with the OF down, but the surface on the right half surface as well. False detection due to roughness is recognized. On the other hand, in FIG. 5b, there is no erroneous detection on the right half surface of the wafer, and uniform detection sensitivity is obtained only on the left half surface.
【0019】以上のように本実施例の膜付きウェーハの
表面検査方法によれば、レーザー入射角度がウェーハに
対して30°の光学系を用いることにより、表面荒れや
膜厚ムラを有した膜付きウェーハの表面検査を高感度で
行なうことができる。As described above, according to the method for inspecting the surface of the film-coated wafer of this embodiment, the film having the surface roughness and the film thickness unevenness is used by using the optical system in which the laser incident angle is 30 ° with respect to the wafer. The surface inspection of the attached wafer can be performed with high sensitivity.
【0020】[0020]
【発明の効果】以上のように本発明は、レーザー入射角
度がウェーハに対して鋭角の光学系を用いることによ
り、表面荒れや膜厚ムラを有する膜付きウェーハの表面
検査を高感度で行なうことができる。INDUSTRIAL APPLICABILITY As described above, the present invention enables highly sensitive surface inspection of a film-coated wafer having surface roughness and film thickness unevenness by using an optical system in which the laser incident angle is an acute angle with respect to the wafer. You can
【図面の簡単な説明】[Brief description of drawings]
【図1】本発明の第1の実施例における膜付きウェーハ
の表面検査光学系の概略図FIG. 1 is a schematic diagram of a surface inspection optical system for a film-coated wafer according to a first embodiment of the present invention.
【図2】同実施例におけるレーザー干渉低減作用につい
ての説明図FIG. 2 is an explanatory view of a laser interference reducing action in the same embodiment.
【図3】同実施例における表面荒れによるノイズ成分の
低減作用についての説明図FIG. 3 is an explanatory diagram of a noise component reducing action due to surface roughness in the example.
【図4】同実施例におけるレーザー干渉低減効果説明の
ための膜付きウェーハ検査結果を示す図FIG. 4 is a diagram showing a film-coated wafer inspection result for explaining a laser interference reducing effect in the example.
【図5】同実施例における表面荒れによるノイズ成分の
低減効果説明のための膜付きウェーハ検査結果を示す図FIG. 5 is a diagram showing a film-coated wafer inspection result for explaining a noise component reducing effect due to surface roughness in the example.
【図6】従来の鏡面ウェーハ表面検査装置の検出光学系
の概略図FIG. 6 is a schematic diagram of a detection optical system of a conventional mirror surface wafer surface inspection apparatus.
1 入射レーザー 2 投光レンズ 3a 異物 3b 表面荒れ 4a ウェーハ 4b 蒸着膜 5 回転テーブル 6 オプティカルファイバー 7a 後方散乱光の中心方向 7b 表面で反射した前方散乱光の中心方向 7c 界面で反射した前方散乱光の中心方向 1 Incident laser 2 Projection lens 3a Foreign matter 3b Surface roughness 4a Wafer 4b Evaporated film 5 Rotating table 6 Optical fiber 7a Center direction of backscattered light 7b Center direction of forward scattered light reflected on the surface 7c Front scattered light reflected at the interface Toward the center
Claims (1)
を入射し、前記レーザースポットの異物による散乱光の
みをオプティカルファイバーによって集光することによ
り、異物を検出する膜付きウェーハの検査において、レ
ーザー入射角度がウェーハに対して鋭角の光学系を用い
たことを特徴とする膜付きウェーハ表面検査方法。1. A laser incident angle in an inspection of a film-coated wafer for detecting a foreign matter by injecting a laser spot on the surface of the wafer and condensing only scattered light by the foreign matter of the laser spot by an optical fiber. Is a method for inspecting a film-coated wafer surface, which uses an optical system having an acute angle with respect to the wafer.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4176596A JPH0618430A (en) | 1992-07-03 | 1992-07-03 | Surface inspection method for wafer with film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4176596A JPH0618430A (en) | 1992-07-03 | 1992-07-03 | Surface inspection method for wafer with film |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0618430A true JPH0618430A (en) | 1994-01-25 |
Family
ID=16016337
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4176596A Pending JPH0618430A (en) | 1992-07-03 | 1992-07-03 | Surface inspection method for wafer with film |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0618430A (en) |
-
1992
- 1992-07-03 JP JP4176596A patent/JPH0618430A/en active Pending
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