JP2006071784A - Confocal microscope, outside appearance inspecting device and semiconductor outside appearance inspecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a confocal microscope capable of compensating the lowering of light quantity caused in the periphery area of the observed image of a sample, capable of successively and easily changing the light quantity of a light source and capable of changing the wavelength of illuminating light. <P>SOLUTION: The confocal microscope is equipped with a light source array 30 comprising a plurality of light sources 40 and positioned on a plane conjugate to the focal plane of an objective 3, and a pinhole array 22 positioned on the plane conjugate to the focal plane of the objective 3 and having apertures 23 at respective positions corresponding to the respective light sources 40 of the light source array 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a confocal microscope, and in particular, a scanning confocal microscope for observing the surface of an inspection object such as a semiconductor integrated device such as a semiconductor wafer, a photomask, and a liquid crystal display device, and an appearance inspection apparatus using the same. About.

  A predetermined pattern is repeatedly formed on a semiconductor wafer, a semiconductor memory photomask, a liquid crystal display panel, or the like. Therefore, an optical image of a pattern is captured using an optical microscope, and a pattern defect is detected by comparing adjacent patterns. As a result of the comparison, if there is no difference between the two patterns, the pattern has no defect, and if there is a difference, it is determined that a defect exists in one of the patterns. In the following description, a semiconductor wafer appearance inspection apparatus that inspects a defect of a pattern formed on a semiconductor wafer will be described as an example. However, the present invention is not limited to this, and can also be applied to an appearance inspection apparatus for inspecting defects such as a semiconductor memory photomask and a liquid crystal display panel.

As such an optical microscope for an appearance inspection apparatus, a confocal microscope as shown in Patent Document 1 below and Patent Document 2 corresponding to US Patent Specification corresponding thereto is used. FIG. 1 is a diagram showing a conventional schematic configuration example of a semiconductor wafer appearance inspection apparatus using a confocal microscope.
As shown in the figure, the semiconductor wafer visual inspection apparatus includes a stage 1 that holds the semiconductor wafer 2, a light source 11, and a large number of minute pinholes that allow illumination light from the light source 11 to pass therethrough as shown in FIG. The first pinhole array 12 that realizes the point light source, the illumination lens 13, and the illumination light that passes through the first pinhole array 12 are condensed on the condensing surface of the semiconductor wafer 2 surface, and the surface of the semiconductor wafer 2 An objective lens 3 for projecting the optical image, a semi-transparent mirror (beam splitter) 14 provided in the projection optical path of the objective lens 3, and an image of the surface of the semiconductor wafer 2 projected by the objective lens 3 are further described below. 4 and a second pin provided with a large number of minute pinholes provided at a position conjugate with the first pinhole array 12 and allowing only focused light to pass therethrough. Comprising a confocal microscope 10 having a hole array 22, a.

  Further, the semiconductor wafer appearance inspection apparatus outputs an optical image of the surface of the semiconductor wafer 2 that has passed through the second pinhole array 22 to an electrical image signal, and is output from the image sensor 4. An image signal processing circuit 5 that processes the analog image signal and converts it into multi-valued digital image data, and a digital image data processing circuit 6 that processes the digital image data and compares the same part of the pattern to detect defects And an image data memory 7 for storing image data for data processing.

  In such a confocal microscope, only the reflected light that illuminates the surface of the semiconductor wafer 2 at the focal position where the illumination light from the point light source is collected by the objective lens 3 and forms an image on the second pinhole array 22, Since it passes through each pinhole on the second pinhole array 22 and is projected onto the imaging device 4 and other light is excluded, a clear image free from noise due to defocusing or leakage light can be obtained.

  As the imaging device 4, a TV camera using a two-dimensional CCD element can be used. However, in order to obtain a high-definition image signal, a line sensor such as a one-dimensional CCD is used, and the stage 1 is used. In many cases, the image signal processing circuit 5 captures the signal of the line sensor 4 and acquires an image in synchronization with the drive pulse signal for driving the stage 1. .

JP-A-10-326587 US Pat. No. 6,429,897

  However, in the configuration of the conventional confocal microscope, even if the light amount decreases in the peripheral region of the optical image of the sample surface projected on the imaging device 4 due to the decrease in the illumination light amount in the peripheral region of the field of view of the objective lens 3, Since the amount of light cannot be partially increased or decreased, there is a problem that such a decrease in the amount of peripheral light cannot be compensated.

  Furthermore, when observing the surface of the sample 2 that is larger than the field of view of the objective lens 3 of the confocal microscope, the field of view of the objective lens 3 is scanned on the surface of the large sample 2, but the surface of the sample 2 has a high pattern density, for example. When there are a plurality of different regions, the brightness of the observation image varies greatly depending on the scanning position. When observing such a sample 2, it is preferable to sequentially change the light source light amount in accordance with the scanning position of the field of view of the objective lens 3 to keep the brightness of the observation image within a predetermined range. In the microscope, it is difficult to control the light source light amount in accordance with the visual field position of the objective lens 3 that scans at high speed.

  Further, when the surface of the sample 2 has a region formed of, for example, a plurality of different substances, the optical reflectance of the object depends on the material of the object, so that the illumination light depends on the scanning position of the field of view of the objective lens 3. It is preferable to illuminate with a suitable reflectance by sequentially changing the wavelength. For example, copper used for a wiring portion of a semiconductor circuit has a property of high reflectivity in the visible light region, but the reflectivity is low in the wavelength region near 350 nm, and the reflectivity decreases. However, the conventional confocal microscope has not been configured to change the wavelength of the illumination light.

  In view of the above problems, an object of the present invention is to provide a confocal microscope that can compensate for a decrease in the amount of light that occurs in a peripheral region of an observation image of a sample. It is another object of the present invention to provide a confocal microscope capable of sequentially changing the light source light amount according to the scanning position of the field of view of the objective lens 3. Furthermore, it aims at providing the confocal microscope which can change the wavelength of illumination light.

In order to achieve the above object, the confocal microscope according to the present invention realizes the above-described many point light sources by a light source array including a plurality of light sources.
That is, the confocal microscope according to the present invention includes a light source array composed of a plurality of light sources positioned on a plane conjugate to the focal plane of the objective lens, and a light source array positioned on a plane conjugate to the focal plane of the objective lens. A pinhole array having an opening at each corresponding position.

The confocal microscope according to the present invention may include a reflective optical system in which a mirror array device is arranged on a plane conjugate with the focal plane of the objective lens, instead of the pinhole array.
In addition, the light source array may include a plurality of light sources having different emission wavelengths. In this case, the confocal microscope is configured to illuminate the sample by selecting a light source that emits light from the light source array. You may provide the light source control part which changes the wavelength of light.
Furthermore, each light source can be realized using a semiconductor light emitting element such as a light emitting diode or a laser diode.

  The confocal microscope according to the present invention is provided in an appearance inspection apparatus, and can be used for observing a pattern formed on the surface of a sample and performing an appearance inspection of the pattern. Furthermore, the confocal microscope according to the present invention is provided in a semiconductor appearance inspection apparatus, and can be used for observing a pattern formed on the surface of a semiconductor wafer and inspecting the appearance of the pattern.

By realizing the above-described many point light sources with a light source array composed of a plurality of light sources, it is possible to adjust the light amount for each individual light source to compensate for the decrease in the light amount that occurs in the peripheral region of the observation image of the sample. .
Further, by using a semiconductor light emitting element for each light source, it is possible to quickly adjust the light amount, and to sequentially change the light source light amount according to the scanning position of the field of view of the objective lens 3.
Furthermore, the light source array includes a plurality of light sources having different emission wavelengths, and further includes a light source control unit that selects a light source to emit light from the light source array, so that the wavelength of the illumination light can be changed. Become.
At this time, instead of the pinhole array, a reflection optical system that arranges the mirror array device on a plane conjugate to the focal plane of the objective lens is provided, and the light source control unit selects from among the many mirrors arranged in the mirror array device. Only the mirror corresponding to the position of the light source element that emits light is controlled so that the projection light from the objective lens is reflected on the projection surface of the observation image such as the imaging surface of the imaging device, and the other mirrors are controlled in other directions. Thus, the same effect as each pinhole in the pinhole array can be obtained.
As a result, even if the position of the light source changes by selecting the light source element that the light source control unit emits, the pin that controls the direction of each mirror of the mirror array device and changes the position of each pinhole accordingly. A hole array can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a diagram showing an optical system portion of the semiconductor wafer appearance inspection apparatus according to the first embodiment of the present invention. Other portions shown in FIG. 1 are omitted here. Further, in the following description, a semiconductor wafer appearance inspection apparatus for inspecting a defect of a pattern formed on a semiconductor wafer will be described as an example, but the present invention is not limited to this, and a photomask for a semiconductor memory, Further, it can be widely applied to an appearance inspection apparatus for inspecting semiconductor devices such as liquid crystal display panels.

  As shown in FIG. 2, the defect inspection apparatus for a semiconductor wafer according to the present embodiment uses a stage 1 for holding a semiconductor wafer 2, a light source array 30, an illumination lens 13, and illumination light from the light source array 30 to the semiconductor wafer. An objective lens 3 for condensing light on the two condensing surfaces and projecting an optical image of the surface of the semiconductor wafer 2; a semi-transparent mirror (beam splitter) 14 provided in the projection optical path of the objective lens 3; Is provided at a position conjugate to the focal plane of the objective lens 3 and a lens 21 that further projects the image of the surface of the semiconductor wafer 2 projected onto the image sensor 4 to be described later, and passes only the light focused at this position. A pinhole array 22 having a large number of pinholes.

The light source array 30 is provided with a large number of two-dimensionally arranged micro light source elements 40 that are substantially point light sources on the light emitting surface thereof, and is provided at a position conjugate with the focal plane of the objective lens 3.
Therefore, the illumination light from the micro light source element 40 which is a point light source is condensed on the surface of the semiconductor wafer 2 by the objective lens 3 and reflected at the focal position of the objective lens 3 out of the light reflected here, and is reflected by the pinhole array 22. Only the reflected light that forms an image on the top passes through each pinhole on the pinhole array 22 and is projected onto the imaging device 4. As a result, the imaging device 4 can acquire a clear image free from noise due to defocusing or leakage light.
As the minute light source element 40, a semiconductor light emitting element such as a light emitting diode or a laser diode can be used.

  The image sensor 4 is preferably a one-dimensional line sensor such as TDI. Then, the stage 1 is driven, the semiconductor wafer 2 is moved relative to the image sensor 4 (scanned), and the image signal processing circuit 5 is synchronized with the drive pulse signal from the stage controller 96 that drives the stage 1. Captures the signal of the line sensor 4 and acquires an image. It is also possible to use a TV camera using a two-dimensional CCD element.

FIG. 3A is a diagram showing the light source array 30 and a large number of micro light source elements 40 arranged thereon, and FIG. 3B is a diagram illustrating a large number of illumination parts by the light source array 30 of FIG. FIG. 3C is a diagram showing the semiconductor wafer 2 that generates the (spot portion) 8, and FIG. 3C is a diagram showing the pinhole array 22 and a large number of minute pinholes 23 provided thereon.
In FIG. 3A, all white circles in the figure indicate micro light source elements. However, for the sake of simplicity, only the micro light source elements 40a to 40f are provided with reference numerals and the others are omitted. Similarly, in FIG. 3B, all white circles in the figure indicate spot portions, but only the spot portions 8a to 8f are denoted by reference numerals and the others are omitted. Further, in FIG. 3C, all white circles in the drawing indicate minute pinholes, but only the minute pinholes 23a to 23f are denoted by reference numerals and the others are omitted.

Illumination images from the micro light source elements 40a to 40f that are point light sources are formed on the semiconductor wafer 2 at the positions of the spot portions 8a to 8f, respectively, and illuminate these portions.
When the semiconductor wafer 2 moves relative to the image sensor 4 in the direction of the arrow S in the figure by driving the stage 1, the micro light source elements 40 a to 40 f have spot portions 8 a to 8 f in the observation region on the semiconductor wafer 2. Arranged to scan all. For example, in the arrangement example of FIG. 3A, the direction of the element array composed of the minute light source elements 40a to 40f arranged at equal intervals is set, and the direction of the corresponding spot portions 8a to 8f is the scanning direction S of the semiconductor wafer 2. The element rows are arranged at equal intervals in the direction orthogonal to the extending direction, and the positions in the extending direction of the element rows are sequentially shifted by equal distances.

  As shown in FIG. 3 (C), the pinhole array 22 has image forming positions at which illumination light from the micro light source elements 40a to 40f reflected on the semiconductor wafer 2 at the focal position of the objective lens 3 forms an image. 23 a to 23 f have minute pinholes, and only the light imaged at these positions passes through the imaging device 4.

  Since each light source arranged in the light source array 30 is composed of individual micro light source elements 40, it is possible to individually increase or decrease the amount of light. Therefore, for example, when the illumination light amount in the peripheral region of the visual field of the objective lens 3 is reduced and the light amount is reduced in the peripheral region of the optical image of the sample surface projected on the imaging device 4, the periphery of the visual field of the objective lens 3 is obtained. It is also possible to increase the amount of light of the micro light source element 40 that illuminates the region and decrease the amount of light of the micro light source element 40 that illuminates the central region of the field of view of the objective lens 3. In the semiconductor wafer defect inspection apparatus, the light source control unit 95 capable of individually increasing / decreasing the amount of light of each micro light source element 40 of the light source array 30 as described above, and each of the light source array 30 disposed at each position on the light source array 30. A micro light source element 40 and a storage unit 94 that stores a look-up table that correlates each light emission amount are provided. The light source control unit 95 refers to a lookup table stored in the storage unit 94 (for example, when the micro light source element 40 is a semiconductor light emitting element such as a light emitting diode or a laser diode, the drive current is increased or decreased. ) It is possible to increase or decrease the amount of light emitted from each micro light source element 40.

  Further, when the micro light source element 40 is a semiconductor light emitting element such as a light emitting diode or a laser diode, the amount of light can be easily increased or decreased by increasing or decreasing its driving current. Therefore, when the surface of the semiconductor wafer 2 includes a region having a significantly different reflectance, the light source control unit 95 determines the reflectance of the region on the surface of the semiconductor wafer 2 captured in the field of view of the objective lens 3 currently being scanned. Accordingly, it is possible to sequentially increase or decrease the amount of light emitted from the micro light source element 40. That is, the light source control unit 95 performs control to increase the amount of emitted light when the scanning position of the field of view of the objective lens 3 is in a region with low reflectivity, and to decrease the amount of emitted light when in the region with high reflectivity. Do. For example, the memory cell region formed on the surface of the semiconductor wafer 2 has a low reflectance because of high pattern density, while the logic circuit region and the peripheral circuit region (peripheral region) have a high reflectance because of low pattern density.

Thus, in order to control the light quantity of the micro light source element 40 according to the pattern on the surface of the semiconductor wafer 2 within the field of view of the objective lens 3, the appearance inspection apparatus of the present embodiment uses a computer or the like as shown in FIG. The type information indicating the computer 91 that can be realized and the reflectance, pattern density, or memory cell area, logic circuit area, or peripheral circuit area of each pattern area formed at each position on the semiconductor wafer 2 is shown. And an input / output unit 93 for inputting pattern data.
The storage unit 94 stores the pattern data input from the input / output unit 93, and the light source control unit 95 is placed on the stage 1 based on the position information of the stage 1 output from the stage control unit 96. The reflectance, pattern density, or type information of the pattern area formed at each position on the semiconductor wafer 2 is read from the storage unit 64, and the micro light source element 40 is read according to the read reflectance, pattern density, or type information. The amount of light increases or decreases sequentially. At this time, the light source control unit 95 can also control the light amount of each micro light source element 40 arranged at each position on the light source array 30 by using the look-up table at the same time.

  A plurality of micro light source elements 40 having different light emission wavelengths are arranged in the light source array 30, and the light source control unit 95 selects the light source elements 40 to emit light for each light emission wavelength. It is also possible to change the wavelength. 4A is a diagram showing a light source array 30 in which a plurality of micro light source elements 41a to 41c having different emission wavelengths are arranged, and FIG. 4B is a diagram showing each micro light source array 30 in FIG. 4A. It is a figure which shows the pinhole array 22 which arrange | positions the micro pinhole 23 corresponding to arrangement | positioning of a light source element.

As shown in FIG. 4A, the light source array 30 includes a plurality of light source array substrates 31a to 31c on which the micro light source elements 41a to 41c are respectively arranged by the same arrangement method as the light source array 30 shown in FIG. I have. The light emission wavelengths of the plurality of minute light source elements arranged in one light source array substrate are all the same, but the minute wavelengths arranged on different light source array substrates 31a and 31b, 31b and 31c, and 31a and 31c, respectively. The light emission wavelengths of the light source elements 41a and 41b, 41b and 41c, and 41a and 41c are different.
In FIG. 4A, the white circles shown in the light source array substrates 31a to 31c all indicate the micro light source elements 41a to 41c, but only one of them is given a reference numeral for the sake of simplicity of the drawing. Others are omitted. Similarly, in FIG. 4B, all the white circles in the figure indicate the minute pinholes 23, but only one of them is given a reference numeral and the others are omitted.

  Then, the light source controller 95 changes the wavelength of the illumination light that illuminates the semiconductor wafer 2 by switching the micro light source elements 41a to 41c that emit light for each emission wavelength (that is, for each light source array substrate 31a to 31c). In addition, the light source control unit 95 can select a combination of a plurality of micro light source elements 41a to 41c that emit light at different emission wavelengths and emit light simultaneously.

FIG. 5A is a diagram showing another embodiment of the light source array 30 in which a plurality of micro light source elements having different emission wavelengths are arranged, and FIG. 5B is a diagram of the light source array 30 in FIG. It is a figure which shows the pinhole array 22 which arrange | positions a micro pinhole corresponding to arrangement | positioning of each micro light source element.
The light source array 30 shown in FIG. 5A includes light source array substrates 31a, 31b, 31c, 32a, 32b, 32c,... 38a, 38b, and 38c each having a row of micro light source elements 41a to 41c. Are arranged in a direction perpendicular to the extending direction.
In FIG. 5A, the white circles shown in the light source array substrates 31a to 38a all indicate the micro light source elements 41a, and the white circles shown in the light source array substrates 31b to 38b are all micro light sources. The white circles indicating the element 41b and shown in the light source array substrates 31c to 38c all indicate the micro light source elements 41c, but for simplicity of the drawing, only one of them is given a reference numeral and the others are omitted. Similarly, in FIG. 5B, all white circles in the figure indicate the minute pinholes 23, but only one of them is given a reference numeral and the others are omitted.

  Each light source array substrate 31a, 32a,... 37a and 38a has micro light source elements 41a having the same emission wavelength arranged in a line at equal intervals, and each light source array substrate 31b, 32b,. The minute light source elements 41b having the same wavelength are arranged in a line at equal intervals, and the light source elements 41c having the same emission wavelength are arranged in a line on the light source array substrates 31c, 32c,. Is done. The light emission wavelengths of the micro light source elements 41a and 41b, 41b and 41c, and 41a and 41c are different.

  The light source array substrates 31a, 31b, 31c, 32a, 32b, 32c,... 38a, 38b, and 38c constitute light source array substrate groups 31 to 38, and the light source array substrates 31a, 31b, and 31c belong to the group 31. The light source array substrates 32a, 32b, and 32c are in the group 32, the light source array substrates 33a, 33b, and 33c are in the group 33, the light source array substrates 34a, 34b, and 34c are in the group 34, and the light source array substrates 35a, 35b, and 35c are the group 35. The light source array substrates 36a, 36b, 36c belong to the group 36, the light source array substrates 37a, 37b, 37c belong to the group 37, and the light source array substrates 38a, 38b, 38c belong to the group 38.

  In the light source array substrates 31a to 31c, 32a to 32c,... 38a to 38c belonging to the same group, the rows of the micro light source elements 41 arranged thereon are equally arranged in the extending direction. In the light source array substrates 31a to 38a, 31b to 38b, and 31c to 38c belonging to different groups, similarly to the relationship between the respective light source element rows shown in FIG. The rows are arranged so that the positions in the extending direction are sequentially shifted by equal distances.

  As in the case of the light source array 30 shown in FIG. 4A, the light source control unit 95 switches the micro light source elements 41a to 41c to emit light for each emission wavelength (that is, for each light source array substrate 31a to 31c). The wavelength of the illumination light that illuminates the semiconductor wafer 2 is changed. In addition, the light source control unit 95 can select a combination of a plurality of micro light source elements 41a to 41c that emit light at different emission wavelengths and emit light simultaneously.

By configuring the light source array 30 as shown in FIGS. 4A and 5A, the semiconductor wafer defect inspection apparatus can change the emission wavelength of the illumination light that illuminates the semiconductor wafer 2. Therefore, for example, when a pattern is formed with a plurality of different substances on the surface of the semiconductor wafer 2, a micro light source that emits light with an emission wavelength corresponding to the optical reflectance of each substance existing at the scanning position of the field of view of the objective lens 3. By selecting the elements 41a to 41c to emit light, it is possible to illuminate with a suitable reflectance.
For this purpose, the pattern data input to the input unit 93 and stored in the storage unit 94 includes information on the wavelength of the illumination light suitable for illuminating each region on the semiconductor wafer 2 with respect to the pattern forming substance or the region. The light source control unit 95 reads out pattern data related to the pattern in the field of view of the objective lens 3 from the storage unit 64 based on the position information of the stage 1 output from the stage control unit 96, and minute data that matches the data. The light source elements 41a to 41c are selected to emit light.
At this time, the light source control unit 95 can also control the light amount of each micro light source element 40 arranged at each position on the light source array 30 by using the lookup table at the same time. As described above, it is possible to increase or decrease the amount of light emitted by the micro light source element 40 in accordance with the pattern in the field of view of the objective lens 3.

FIG. 6 is a diagram showing an optical system portion of a semiconductor wafer appearance inspection apparatus according to the second embodiment of the present invention. In this embodiment, instead of the pinhole array 22 in the semiconductor wafer appearance inspection apparatus according to the first embodiment of the present invention shown in FIG. 2, the mirror array device 50 is arranged on a plane conjugate with the focal plane of the objective lens 3. An optical system is provided.
A large number of very fine minute mirror elements 51 are spread on the surface (reflection surface) of the mirror array device 50, and the reflection angle can be controlled for each of these many minute mirror elements 51. As such a mirror array device 50, a digital micromirror device (DMD) (trademark) of Texas Instruments can be used.

  For example, when the light source array 30 described above with reference to FIG. 3A is used, among the minute mirror elements 51 of the mirror array device 50, the pinhole described above with reference to FIG. An image of the semiconductor wafer 2 projected through the projection lens 21 only through the minute mirror elements 51 arranged in the regions corresponding to the respective hole regions of the micro pinholes 23 of the array 22 is imaged through the projection lens 24. The direction of reflection on the imaging surface of the sensor 4 is controlled, and the other micromirror elements 51 are controlled in other directions. As a result, the mirror array device 50 can achieve the same effect as the pinhole array 22.

  Similarly, when the light source array 30 described above with reference to FIGS. 4A and 5A is used, the pins described above with reference to FIGS. 4B and 5B, respectively. The micromirror element 51 arranged in the region corresponding to the micro pinhole of the hole array 22 is controlled so that the projected image of the semiconductor wafer 2 is reflected on the imaging surface of the image sensor 4, and other micromirror elements By controlling 51 in the other direction, the same effect as the pinhole array 22 can be obtained.

  In particular, when the light source array 30 described above with reference to FIG. 5A is used, by providing the mirror array device 50, the micro light source elements 41a to 41c having different emission wavelengths belonging to the same light source array substrate group. It is possible to provide the arrangement interval between the pinhole arrays 22 smaller than the arrangement interval between the minute pinholes 23.

In other words, the minute pinholes 23 of the pinhole array 22 pass adjacent unfocused light rays projected onto the peripheral region of the adjacent minute pinholes 23 to avoid adverse effects on the captured image. 23 need to be separated from each other by about 4 times the pinhole diameter. The arrangement interval of the minute light source elements is also set in the same manner as the arrangement interval of the minute pinholes.
In the pinhole array 22 shown in FIG. 5B, since all the minute pinholes 23 corresponding to all the minute light source elements 41a to 41c are always opened, different emission wavelengths belonging to the same light source array substrate group. When the arrangement interval of the micro light source elements 41a to 41c is narrowed to less than about four times the pinhole diameter, the arrangement interval of the micro pinholes 23 is reduced accordingly, and adjacent micro light source elements are affected. Therefore, the arrangement interval of the micro light source elements 41a to 41c having different emission wavelengths belonging to the same light source array substrate group cannot be reduced.

Therefore, the micro light source elements 41a to 41c having different emission wavelengths are caused to emit light at different timings for each emission wavelength without simultaneously emitting light, and only the micro mirror element 51 corresponding to the position of the emitted micro light source element is projected. Control is performed so that the image of the wafer 2 is reflected by the imaging surface of the image sensor 4.
In this way, for example, when the micro light source elements 41a having a certain emission wavelength in each of the light source array substrate groups 31 to 38 emit light, the positions of the micro light source elements 41a on the reflection surface of the mirror array device 50 are accommodated. It is possible to form the reflection surface to the imaging surface of the image sensor 4 only at the position where the image sensor 4 is to be formed and not at the position corresponding to the positions of the micro light source elements 41b and 41c having other emission wavelengths.
Therefore, even if the arrangement interval of the micro light source elements 41a to 41c having different emission wavelengths belonging to the same light source array substrate group is narrowed, the interval between the regions for forming the reflection surface to the imaging surface of the image sensor 4 is set to the conventional pinhole 23. It is possible to provide a sufficiently large diameter as compared with the diameter of.

  By making it possible to install the micro light source elements 41a to 41c having different emission wavelengths belonging to the same light source array substrate group by narrowing the arrangement interval, the size of the light source array 30 can be saved, and the scanning distance of the semiconductor wafer 2 is also increased. Since it can be shortened, it helps to save inspection time.

  The control method of each of the micro light source elements 41a to 41c when using the semiconductor wafer appearance inspection apparatus according to the second embodiment of the present invention is the same as that of the semiconductor wafer appearance inspection apparatus according to the first embodiment described above. Therefore, the description is omitted.

  The present invention relates to a confocal microscope, particularly a scanning confocal microscope for observing the surface of an object to be inspected such as a semiconductor integrated device such as a semiconductor wafer, a photomask, and a liquid crystal display device, and an appearance inspection apparatus using the same. Is available.

It is a figure which shows the conventional schematic structural example of the external appearance inspection apparatus for semiconductor wafers which uses a confocal microscope. It is a figure which shows the optical system part of the external appearance inspection apparatus for semiconductor wafers which concerns on 1st Example of this invention. (A) is a figure which shows a light source array and many micro light source elements arrange | positioned on it, (B) is a figure which shows the semiconductor wafer which produces many spot parts by the light source array of (A). (C) is a figure which shows a pinhole array and many micro pinholes provided in it. (A) is a figure which shows the light source array which arrange | positions several micro light source elements of a different light emission wavelength, (B) is a micro pinhole corresponding to arrangement | positioning of each micro light source element of the light source array of (A). It is a figure which shows the pinhole array which arrange | positions. (A) is a figure which shows the other Example of the light source array which arrange | positions the micro light source element of several different light emission wavelength, (B) is arrangement | positioning of each micro light source element of the light source array 30 of (A). It is a figure which shows the pinhole array which arrange | positions a micro pinhole correspondingly. It is a figure which shows the optical system part of the external appearance inspection apparatus for semiconductor wafers concerning 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage 2 Semiconductor wafer 3 Objective lens 4 Imaging device 13, 21 Lens 14 Semi-transparent mirror 14
22 pinhole array 30 light source array 40 micro light source element

Claims (7)

  A light source array composed of a plurality of light sources located on a plane conjugate to the focal plane of the objective lens, and an opening at each position corresponding to each light source of the light source array located on a plane conjugate to the focal plane of the objective lens A confocal microscope comprising: a pinhole array.   A light source array comprising a plurality of light sources positioned on a plane conjugate to the focal plane of the objective lens, and a reflective optical system in which a mirror array device is arranged on a plane conjugate to the focal plane of the objective lens. Confocal microscope.   The confocal microscope according to claim 1, wherein the light source array includes a plurality of light sources having different emission wavelengths.   The confocal microscope according to claim 3, further comprising a light source control unit that changes a wavelength of illumination light that illuminates the sample by selecting the light source to emit light from the light source array.   The confocal microscope according to claim 1, wherein the light source is a semiconductor light emitting element.   An appearance inspection apparatus characterized by observing a pattern formed on a sample surface by the confocal microscope according to any one of claims 1 to 5 and performing an appearance inspection of the pattern.   6. A semiconductor appearance inspection apparatus, wherein a pattern formed on the surface of a semiconductor wafer is observed by the confocal microscope according to claim 1 to perform an appearance inspection of the pattern.

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