JP2000114503A - Solid-state imaging device and aberration measurement device - Google Patents

Abstract

(57) [Summary] The present invention relates to a solid-state imaging device that captures a specific pattern image. The present invention also relates to an aberration measurement device that measures aberration of the optical system based on a specific pattern image formed by the optical system. It is another object of the present invention to provide a solid-state imaging device that can accurately capture a pattern image having a large difference in illuminance by adjusting the light receiving ratio of each light receiving element. In a solid-state imaging device including a plurality of light receiving elements for receiving a specific pattern image, a plurality of light receiving elements (P) are provided.
Comprises a dimming unit 20 for dimming a specific pattern image corresponding to at least a part of the light receiving element, and the light receiving ratio of each light receiving element set by the dimming unit is set to be equal to each light receiving element of the specific pattern image. Is set in advance to a value corresponding to the illuminance distribution corresponding to.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device for picking up a specific pattern image. The present invention also relates to an aberration measurement device that measures aberration of the optical system based on a specific pattern image formed by the optical system.

[0002]

2. Description of the Related Art In recent years, formation of a fine pattern such as a semiconductor circuit pattern is performed by a photolithography method or the like. Among them, the mainstream is a reduced projection method in which an enlarged master (reticle) of a circuit pattern is reduced by an optical system and then transferred to an object to be exposed. At present, the resolution required for forming such a pattern is 0.
It has increased to about 1 μm.

However, the shape of the pattern is greatly affected by the aberration of the optical system used. In order to form a desired pattern while improving the resolution, the aberration must be measured in advance. Is required. Although there are several methods for measuring the aberration of the optical system, there is a phase recovery method that is advantageous in that the aberration can be obtained with a relatively compact device.

FIG. 8 is a diagram showing the principle of an aberration measuring apparatus to which the phase recovery method is applied. In applying the phase recovery method, first, as shown in FIG. 8, a specific pattern image such as a hole pattern 82 is formed by an optical system (optical system to be measured) 81 which is a target of aberration measurement. Statue cc
An image is captured by a D (solid-state imaging device) 83. FIG.
FIG. 8 is a diagram illustrating an example of an intensity distribution of a signal obtained when a CD 83 captures an image of a hole pattern 82; According to FIG. 9, not only the strong signal at the central part 91 but also the peripheral parts 9
2 that a weak signal is generated. This peripheral part 9
The weak signal 2 is affected by the aberration of the test optical system 81.

[0005] Based on the signal including the information on the aberration of the optical system 81 to be inspected, the calculating section 84 shown in FIG.
A predetermined operation based on the phase recovery method is performed. For a detailed description of this phase retrieval method, see U.S. Pat. No. 4,309,60.
Since it is described in the specification of No. 2, it is omitted.

[0006]

As apparent from the intensity distribution in FIG. 9, the image of the hole pattern 82 is
The difference between the illuminance of the central portion 91 and the illuminance of the peripheral portion 92 is very large.

However, in the general CCD 83, only the same accumulation time can be set for all the light receiving elements. Therefore, a relatively short accumulation time is usually set in accordance with the strong illuminance of the central portion 91. As a result, the S / N of the weak signal in the peripheral portion 92 decreases, and the signal corresponding to the weak illuminance in the hole pattern image is buried in the noise.

In the phase recovery method in the arithmetic section 84, arithmetic operations such as Fourier transform are repeatedly performed. In the arithmetic operations, the error in the measurement of the illuminance distribution of the hole pattern image has a great effect. Therefore, conventionally, the accuracy of aberration measurement was poor because each light receiving element of the CCD 83 could not cope with the difference in illuminance.

It is conceivable that a long accumulation time is set for the CCD 83 in accordance with the low illuminance of the peripheral portion 92. However, in practice, the light receiving element in the central portion 91 overflows and blooming, snare and the like occur. Not done because of the problem. Incidentally, in Japanese Patent No. 2555591, the charge generation rate (the number of generated charges with respect to the illuminance) between the light receiving elements is adjusted by changing the impurity concentration of the photodiode used. However, since it is very difficult to control the concentration of impurities, the characteristics of the photodiode vary even when manufactured under the same conditions. Further, if the impurity concentration is changed as described above, the wavelength sensitivity characteristic also changes. Therefore, even if the variation in the characteristic is suppressed, it is necessary to perform a different correction process for each wavelength.

Although Japanese Patent No. 2555591 assumes a light-receiving element having sensitivity in the infrared region, when a light-receiving element having sensitivity in the ultraviolet region is used, Japanese Patent No. 2555981 discloses the same. It is not always possible to change the charge generation rate between light receiving elements in the same manner as described. Therefore, an object of the invention described in claims 1 to 4 is to adjust the light receiving rate of each light receiving element,
An object of the present invention is to provide a solid-state imaging device capable of accurately capturing a pattern image having a large difference in illuminance.

It is another object of the present invention to provide an aberration measuring apparatus capable of accurately measuring the aberration of an optical system to be measured by using the present invention. It is in.

[0012]

According to a first aspect of the present invention, there is provided a solid-state imaging device having a plurality of light receiving elements for receiving a specific pattern image, wherein the plurality of light receiving elements are at least a part of the light receiving elements. The light receiving ratio of each light receiving element set by the light reducing part is a value corresponding to the illuminance distribution corresponding to each light receiving element of the specific pattern image. It is characterized in that it is set in advance.

According to a second aspect of the present invention, in the solid-state imaging device according to the first aspect, the light receiving ratio is set by a size of an opening excluding a light reducing portion formed in each light receiving element. It is characterized by. The third aspect of the present invention is the first aspect.
In the solid-state imaging device described in (1), the light receiving rate is set based on the transmittance of the light reduction unit formed in each light receiving element.

According to a fourth aspect of the present invention, there is provided the solid-state imaging device according to any one of the first to third aspects, further comprising: transfer means for outputting a charge generated by the light receiving element as a signal; A signal correcting unit configured to multiply a signal value output from the light receiving element by a reciprocal of a light receiving rate of the light receiving element to correct the signal value.

According to a fifth aspect of the present invention, there is provided an aberration measuring apparatus for measuring aberration of a test optical system, wherein the aberration measuring device is arranged on at least one of an object side and an image side of the test optical system and specified to the test optical system. 5. A spatial image supply unit for supplying a pattern image of (1) and a measuring unit for measuring a secondary image of the pattern re-imaged by the test optical system, wherein the measuring unit is any one of claims 1 to 4. A solid-state imaging device according to claim 1 is included.

(Operation) According to the first aspect of the present invention, the light receiving ratio of each light receiving element can be adjusted by the dimming unit. Therefore, by setting the light receiving ratio of the light receiving element corresponding to the high illuminance portion of the specific pattern image to be lower than the light receiving ratio of the light receiving element corresponding to the low illuminance portion, the specific pattern image Range can be set according to the illuminance distribution. As a result, even a pattern image having a large difference in illuminance can be accurately imaged.

According to the second aspect of the invention, the light receiving ratio of each light receiving element is set by the size of the opening. In general,
Since the light receiving ratio of the light receiving element is proportional to the area of the opening, a desired light receiving ratio can be easily set by adjusting the area of the opening. In addition, the setting of the light receiving rate by this area adjustment can be performed with high accuracy by a known technique.
Variations in device manufacturing are kept low.

According to the third aspect of the present invention, the light receiving ratio of each light receiving element is set by the transmittance of the light reducing portion. Therefore, the setting of the light receiving rate is realized by applying a material that restricts the light transmittance to the light receiving element. According to a fourth aspect of the present invention, in the solid-state imaging device according to any one of the first to third aspects, the signal correction unit includes:
Since the reciprocal of the light receiving rate of the corresponding light receiving element is multiplied, the output signal value is automatically normalized.

According to the fifth aspect of the present invention, the measuring means includes:
In measuring a secondary image of a specific pattern supplied from the aerial image supply unit, the solid-state imaging device according to any one of claims 1 to 4 is used. Since the solid-state imaging device can accurately capture a pattern image having a large difference in illuminance as described above, the calculation accuracy of the aberration calculation performed based on the result of the imaging also increases as a result.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> First, a first embodiment according to the present invention will be described.
Description will be made based on FIGS. 1, 2, 3, and 4. FIG. This embodiment corresponds to claims 1, 2, and 4.

In the first embodiment, a CCD (solid-state imaging device) that uses a hole pattern image as an object to be imaged will be described. FIG. 1 is a diagram illustrating a planar shape of the CCD 1 according to the first embodiment. The CCD 1 according to the first embodiment uses a conventional C
Like the CD (83 in FIG. 8, reference numeral 83), it has a light receiving surface on which a plurality of light receiving elements P are arranged in a matrix.

The charge generated in each light receiving element P is transferred to a plurality of vertical CCDs 11 (corresponding to transfer means in the claims) arranged in each column of the light receiving surface. Each vertical C
The charge transferred to the CD 11 is transferred to a horizontal CCD 13 (corresponding to a transfer unit in the claims) connected to one end of each vertical CCD 11. In addition, these charges
After being converted into a voltage by an output circuit amplifier 15 connected to the horizontal CCD 13, the voltage is output to the outside.

At the time of this charge transfer, these vertical CCDs
11 is driven in four phases by drive pulses applied to the electrodes φ1 to φ4, and the horizontal CCD 13 is driven by the electrodes φH1 and φH.
2 are driven in two phases by the drive pulse applied to the second and the third drive pulses.
According to the configuration described above, when an image is formed on the light receiving surface of the CCD 1, an image signal indicating the illuminance distribution of the image is output in series from the output circuit amplifier 15.

Here, in the CCD 1 of the first embodiment, the configuration of the light receiving element P is different between an area E1 located at the center of the light receiving surface of the CCD 1 and an area E2 around the area E1. Hereinafter, the light receiving elements P in the region E1 and the region E2
Will be described. FIG. 2 shows the CCD 1 shown in FIG.
, The “region E3” which extends over the region E1 and the region E2 and has two light receiving elements P in both regions.
It is an enlarged view which shows the planar shape of. In FIG. 2, a shaded region is a light shielding film 20 made of an aluminum film or the like.
(Corresponding to the light-reducing portion in FIG. 2).

The region E1 is almost entirely covered by the light-shielding film 20, and the light-shielding film 20 is partially removed at the center of the light-receiving element P (reference numeral P1 in FIG. 2). E9 (corresponding to the opening in claim 2) is formed. On the other hand, in the area E2, as in the related art,
The light-shielding film 20 is almost entirely removed above the light-receiving element P (symbol P2 in FIG. 2), and the opening region E9
A larger opening region E10 is formed (for example,
The area of the opening area E10 is ten times as large as the area of the opening area E9. ).

As a result, the light receiving ratio of the light receiving element P1 is limited to be lower by the smaller the opening area E9 than the opening area E10. FIG. 3 shows the CCD of FIG. 1 according to the first embodiment,
FIG. 2 is a longitudinal sectional view taken along the line XX ′. In FIG. 3, C
CD is a P-type semiconductor substrate 3 made of Si or the like as in the prior art.
A plurality of N-type diffusion layers 32 are formed in a row on a main surface of the light-receiving element P1, the light-receiving element P1, the vertical CCD 11, and the light-receiving element P in order from the X side in the figure.
2. The vertical CCD 11 is configured.

In each of the light receiving elements P1 and P2, the N-type diffusion layer 32 and the P-type semiconductor substrate 31 form a photodiode, and these two photodiodes have the same diffusion area.

Further, on each N-type diffusion layer 32, Si
An insulating film 33 such as O ₂ is formed. Of these, vertical CC
At a position corresponding to the upper part of D11, an electrode (φ4) is formed via an insulating film 33. Furthermore, these electrodes φ4
The light-shielding film 20 made of aluminum or the like is formed on the insulating film 33.

The light shielding film 20 is located above the light receiving element P1.
Above the light receiving element P2, the openings are partially removed to form the above-described opening regions E9 and E10, respectively. The formation of the light-shielding film 20 is performed by a well-known patterning technique or the like, similarly to the formation of the conventional light-shielding film, so that the opening regions E9 and E10 are formed with high accuracy.

Therefore, it is possible to reliably set a desired light receiving rate for the light receiving elements P1 and P2. FIG.
FIG. 4 is a diagram comparing the characteristics of such a light receiving element P1 with the characteristics of the light receiving element P2. The number of electric charges generated in the light receiving elements P1 and P2 increases as the illuminance increases. Both also have photodiodes of the same material and the same diffusion area, so the saturation charge numbers are equal.

In general, the number of electric charges generated in a photodiode increases as the illuminance increases, but the amount of light actually incident on the photodiodes of the light receiving elements P1 and P2 described here is calculated by multiplying the illuminance by the respective light receiving rates. There is a characteristic that the value is obtained. As a result, the measurable illuminance range of the light receiving element P1 is wider than that of the light receiving element P2. On the other hand, the light-receiving element P2 has a narrow measurable illuminance range, but can convert the illuminance in a low value range into a signal in a relatively wide range.

That is, the light receiving element P1 is suitable for imaging a pattern with relatively high illuminance,
Is suitable for imaging a pattern with relatively low illuminance. Here, as shown in FIG. 1, in the CCD 1, a light receiving element P1 having a low light receiving rate is assigned to an area E1 at the center of the light receiving surface, and a light receiving element P2 having a high light receiving rate is assigned to a peripheral area E2.
Is assigned, it is possible to cope with both high illuminance and low illuminance of the hole pattern image as shown in FIG.

Therefore, according to the CCD 1, it is possible to accurately measure the illuminance distribution of a hole pattern image having a large difference in illuminance. In addition, as described above, since the setting of the light receiving ratio of each light receiving element is performed with high accuracy by a known technique, there is an advantage that variations in device manufacturing can be suppressed. In addition,
In FIG. 1, for simplicity, the number of pixels of the CCD 1 is 11 in total.
Although there are two pixels, the actual CCD 1 has about several hundred pixels both vertically and horizontally. In FIG. 1, the central region E1
Corresponds to (6 × 3) pixels at the center of the light receiving surface,
Actually, the central portion 91 where the illuminance of the hole pattern image is high
(16 × 16) to fit the size of (see FIG. 9)
It is assumed to be for a pixel.

The storage time to be set in the CCD 1 is larger than that in the conventional example in which the light receiving rate is not limited.
The light receiving rate of the light receiving element P1 is increased by a lower amount. Alternatively, instead of increasing the accumulation time, the brightness of the light source that generates the hole pattern is increased to increase the illuminance of the entire hole pattern image. In addition, C shown in FIG.
The CD1 is provided with a function described below to normalize signals from the light receiving elements P1 and P2 having different light receiving rates. Note that the CCD 1 with this function is added.
Particularly corresponds to claim 4.

First, as the output circuit amplifier 15 shown in FIG. 1, a variable gain amplifier having a variable gain is used. Further, an output of a gain setting unit 17 (corresponding to a signal correction unit in claims) is connected to a gain adjustment terminal of the output circuit amplifier 15. This gain setting device 17
From the electrodes φ1 to φ4, φH1, and φH2
The drive timing of CD1 is obtained, and based on this timing, it is distinguished whether the signal input to the output circuit amplifier 15 is a signal from the area E1 or a signal from the area E2.

Further, the gain setting device 17 controls the region E
The value G1 is set as the gain of the output circuit amplifier 15 for the signal from 1 and the value G2 is set as the gain of the output circuit amplifier 15 for the signal from the region E2. However,
These values G1 and G2 correspond to the light receiving elements P1 and P2, respectively.
Are determined in advance in accordance with the light receiving rates of.

That is, the characteristics of the photodiode and FIGS.
After calculating the light receiving rates of the light receiving elements P1 and P2 determined by the areas of the opening regions E9 and E10 shown in FIG. 8 by calculation or measurement, the value G1 is set to a constant multiple of the reciprocal of the light receiving rate of the light receiving element P1. , The value G2 is set to the constant multiple of the reciprocal of the light receiving rate of the light receiving element P2. According to such an output circuit amplifier 15 and gain setting device 17, the above-described CCD
The level of the signal output from 1 is automatically normalized.

In the first embodiment, for simplicity, the region E1 in which the light receiving rate is limited to a low level has a rectangular shape, but may have a shape flexibly adapted to the shape of the pattern. Specifically, when the object to be imaged is a hole pattern as described above, the shape of the region E1 may be circular. In the first embodiment, the opening regions formed in the light shielding film 20 include two opening regions E9 and E10.
Although the types are prepared, three or more types of aperture regions may be prepared, and three or more types of light receiving elements P having different light receiving rates may be prepared. In this case, it is possible to more flexibly cope with the difference in the illuminance of the pattern than in the first embodiment.

For example, the area of the opening region of each light receiving element is
If the value is inversely proportional to the illuminance of the corresponding portion of the hole pattern, the S / S of all signals indicating the hole pattern image
N can be made substantially the same before the output circuit amplifier 15, which is convenient.

In this case, the gain value set by the gain setting unit 17 is prepared by the number of types of light receiving elements. <Second Embodiment> Next, a second embodiment according to the present invention will be described.
A description will be given based on FIGS. 1, 5 and 6. This embodiment corresponds to claims 1 and 3.

Here, only the differences from the first embodiment will be described, and the description of the other parts will be omitted. In the second embodiment, the area E of the CCD 1 shown in FIG.
This embodiment is the same as the first embodiment in that different light receiving rates are set for the first light receiving element P1 and the light receiving element P2 in the area E2, but the setting method is different.

FIG. 5 is a longitudinal sectional view of the CCD according to the second embodiment, taken along plane XX 'of FIG. In FIG. 5, FIG.
The same parts as those of the CCD shown in FIG. The photodiodes constituting the light receiving elements P1 and P2 according to the second embodiment include surface P layers 51 and 52 made of a P-type semiconductor between an N-type diffusion layer 32 and an insulating film 33, respectively.
This is a buried photodiode in which (corresponding to the darkening portion in claim 3) is formed, that is, a photodiode having a structure in which an N-type diffusion layer 32 is buried in a P-type semiconductor.

In these light receiving elements P1 and P2, the opening regions E9 and E10 formed in both are widened as in the prior art, but instead, the surface P layer 52
The surface P layer 51 is formed thicker than that. FIG. 6 is a diagram showing the light absorption rate of the surface P layer. FIG. 6 shows data in the case where Si is used as the surface P layer.

As shown in FIG. 6, the thicker the surface P layer, the more light is absorbed. Therefore, even if the opening regions E9 and E10 in FIG.
The light receiving ratio is lower than 2. The thickness of each surface P layer is adjusted in advance based on the relationship between the thickness of the surface P layer and the light absorption (transmittance) as shown in FIG. 6, and as a result, the light receiving elements P1 and P2 shown in FIG. A desired light receiving rate is set in P2 as in the first embodiment.

The formation of each of the surface P layers 51 and 52 is performed by N
Since the impurity is implanted into the N-type diffusion layer 32 after the formation of the N-type diffusion layer 32, the surface P layer 5
The thickness adjustment of the layers 1 and 52 is performed by adjusting the energy of the impurity implantation and the impurity concentration at that time, adjusting the number of times of impurity implantation, or adjusting the specific gravity of the impurity. Among them, adjustment by the number of times of impurity implantation is performed, for example, in the following:
Is performed in the following procedure.

An N-type diffusion layer 32 is formed for each of the light receiving elements P1 and P2. The surface P is applied to these N-type diffusion layers 32 under the same conditions.
Impurities for forming the layers 51 and 52 are implanted. By masking only the light receiving element P2, the impurity implantation is performed again only on the light receiving element P1.

As a result, the surface P layer 51 of the light receiving element P1 becomes thicker than the surface P layer 52 of the light receiving element P2 by the number of times of impurity implantation. As described above, depending on the combination of the number of times the above is performed, the surface P layer 51 and the surface P layer 5
2 can have a desired thickness relationship. FIG.
It is clear from the above that, in a light receiving element that receives light of a relatively short wavelength, within a relatively small range from 0 to 0.05 μm, the light receiving ratio is only slightly changed by the thickness of the surface P layer. It changes greatly. Therefore, within this range, a large difference can be made between the light receiving rate of the light receiving element P1 and the light receiving rate of the light receiving element P2 by making only a small change in the thickness of the surface P layer.

Therefore, the CCD of the second embodiment, which adjusts the thickness of the surface P layer when setting the light receiving ratio, is suitable for measuring a hole pattern image in which a light source having a short wavelength in the ultraviolet region is generally used. It is. In the second embodiment,
The adjustment of the light receiving rate was performed by the thickness of the surface P layer of the embedded photodiode, but the present invention is not limited to this, and the same adjustment can be performed by providing a light absorbing layer in a normal photodiode and making a difference in the light absorbing rate. May go.

In addition, the light transmittance of each light receiving element may be adjusted by changing the light transmittance of a sealing glass generally used when a CCD is put in a package.
In this case, the correction content of the output signal can be easily determined by previously measuring the light intensity of each light receiving element by measuring each signal intensity obtained under uniform illumination.

According to this method, it is possible to measure various pattern images with high accuracy only by replacing the sealing glass without changing the configuration of the light receiving element. In this method, since the sensitivity characteristics of each light receiving element may be uniform, the semiconductor process for manufacturing the CCD is performed in the same manner as in the related art. Third Embodiment Next, a third embodiment according to the present invention will be described.
A description will be given based on FIG. This embodiment corresponds to claim 5.

Here, only the differences from the first and second embodiments will be described, and the description of the other parts will be omitted. In the third embodiment, the CCD 1 (see FIG. 1) according to the first or second embodiment is applied to an aberration measuring device. FIG. 7 is a diagram schematically showing such an aberration measuring device.

The aberration measuring apparatus is provided in a projection exposure apparatus for manufacturing a semiconductor, and includes a projection optical system for projecting a circuit pattern on a reticle (or a mask) onto a substrate such as a wafer or a plate, and a test optical system. Is what you do.

On the object side and the image side of the optical system 70 to be inspected,
The aerial image supply unit 71 and the CCD 1 are arranged respectively. The aerial image supply unit 71 includes a measurement illumination optical system 73 that illuminates a test reticle 72 on which a predetermined test pattern is provided, and an image (aerial image) of light transmitted through the test reticle 72 to an intermediate image plane L1 (a Object surface of optical system 70)
And an imaging optical system 74 formed thereon. The test reticle 72 has a hole pattern including a light-shielding portion and a fine light transmitting portion as a test pattern. The imaging optical system 74 in the aerial image supply unit 71 includes lens groups 741 and 742.

The test optical system 70 includes lens groups 701 and 70
2 and an aperture stop 75 disposed therebetween.
The aerial image is re-imaged. On the image side of the test optical system 70, there is provided a CCD 1 (corresponding to a measuring means in the claims) in which a light receiving surface is arranged on the re-imaging surface. CCD
As described in the first embodiment and the second embodiment, each light receiving element 1 is designed to correspond to the hole pattern.

The central control unit (CCU) 76 (corresponding to the measuring means in the claims) performs a predetermined calculation based on the illuminance distribution of the hole pattern image obtained via the CCD 1 and Find the aberration. In the aberration measuring apparatus having the above-described configuration, the CCD 1 measures the illuminance distribution with high accuracy for the same reason as in the first and second embodiments, and as a result, the aberration performed based on the illuminance distribution The accuracy of the measurement is increased.

In the third embodiment, if the above-described gain setting unit 17 (see FIG. 1) is not provided in the CCD 1 of FIG. 7, the gain setting is performed during the calculation by the central control unit 76. The same correction as that performed by the device 17 is performed. In the third embodiment,
The test pattern formed on the test reticle 72 may be any pattern such as a line and space pattern as long as it is a predetermined specific pattern. Also in this case, each light receiving element of the CCD 1 is designed according to the test pattern. Since the pattern captured by the CCD 1 has a low illuminance portion and a high illuminance portion corresponding to the light shielding portion and the light transmitting portion of the test pattern, the light receiving element corresponding to the light shielding portion has a high light receiving rate,
A low light receiving rate is set for the light receiving element corresponding to the transmitting part. This setting method may be any of the first embodiment and the second embodiment described above.

The CCD described above can be applied to, for example, each aberration measuring device described in Japanese Patent Application Laid-Open No. H10-170399. Specifically, each of the above-mentioned CCDs is provided in place of the “image position measuring system” in each of the aberration measuring devices described in JP-A-10-170399. This aberration measurement device measures the light beam from the aerial image supply unit by limiting it to a partial area on the pupil of the test optical system, and measures the aberration at a desired position on the pupil of the test optical system. However, the above CCDs can be easily applied to such an aberration measuring device. Also in this case, the design of each light receiving element of the CCD is performed according to the shape of the test pattern used in the device.

The CCD of the present invention can also be applied to semiconductors, wafers and other inspection devices and observation devices.

[0059]

As described above, according to the first aspect of the present invention, a range suitable for the illuminance distribution of a specific pattern image can be set for each light receiving element by adjusting the light receiving ratio. It is possible to accurately capture an intense pattern image.

According to the second aspect of the present invention, a desired light receiving rate can be set for each light receiving element by adjusting the area of the opening. In addition, since the setting of the light receiving ratio by the area adjustment can be performed with high accuracy, variations in device manufacturing can be suppressed low.

According to the third aspect of the present invention, the setting of the light receiving rate is realized by applying a material for limiting the light transmittance to the light receiving element. According to the fourth aspect of the present invention, the output signal value is automatically normalized by a correction by a simple operation. According to the fifth aspect of the invention, in the first aspect,
Since the solid-state imaging device according to claim 4 is used, the accuracy of aberration measurement can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a planar shape of a CCD according to a first embodiment.

FIG. 2 is an enlarged view showing a planar shape of a region E3 which straddles a region E1 and a region E2 and has two light receiving elements P in both regions.

FIG. 3 is a cross-sectional view of the CCD according to the first embodiment;
It is a longitudinal cross-sectional view in the X 'plane.

FIG. 4 is a diagram comparing characteristics of the light receiving element P1 and characteristics of the light receiving element P2.

FIG. 5 is a cross-sectional view of the CCD according to the second embodiment taken along plane XX ′ of FIG. 1;

FIG. 6 is a diagram showing a light absorption rate of a surface P layer.

FIG. 7 is a view schematically showing an aberration measuring device.

FIG. 8 is a diagram illustrating the principle of the aberration measurement device.

FIG. 9 is a diagram illustrating an example of an intensity distribution of a signal obtained when a CCD captures a hole pattern image.

[Description of Signs] 1,83 CCD P light receiving element 11 vertical CCD 13 horizontal CCD 15 output circuit amplifier 17 gain setting unit E area φ1 to φ4, φH1, φH2 electrode 20 light shielding film 31 P-type semiconductor substrate 32 N-type diffusion layer 33 Insulating film 70 Test optical system (projection optical system) 71 Spatial image supply unit 701, 702 Lens group 72 Test reticle 73 Measurement illumination optical system 74 Imaging optical system 75 Aperture stop 76 Central control unit (CCU) L1 Intermediate image plane Reference Signs List 81 optical system to be tested 82 hole pattern 84 operation unit 91 central part 92, 93 peripheral part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G086 EE01 EE04 HH06 4M118 AA02 AB01 AB10 BA10 CA03 CA04 CA26 DA03 DB06 DB08 FA06 GB11 HA02 5C024 AA01 CA15 EA08 FA01 FA11 GA11 GA52 JA23 JA25

Claims (5)

[Claims] 1. A solid-state imaging device including a plurality of light receiving elements for receiving a specific pattern image, wherein the plurality of light receiving elements diminish the specific pattern image corresponding to at least a part of the light receiving elements. A light reduction unit, wherein the light receiving rate of each light receiving element set by the light reduction unit is set in advance to a value corresponding to an illuminance distribution corresponding to each light receiving element of the specific pattern image. Solid-state imaging device. 2. The solid-state imaging device according to claim 1, wherein the light receiving ratio is set by a size of an opening excluding a light reducing portion formed in each light receiving element. 3. The solid-state imaging device according to claim 1, wherein the light receiving ratio is set by a transmittance of a light reduction unit formed in each light receiving element. 4. A transfer means for outputting a charge generated in the light receiving element as a signal, a signal value output from each light receiving element being multiplied by a reciprocal of a light receiving rate of the light receiving element, and The solid-state imaging device according to any one of claims 1 to 3, further comprising a signal correction unit that corrects a value. 5. An aberration measuring apparatus for measuring an aberration of a test optical system, wherein the test pattern is arranged on at least one of an object side and an image side of the test optical system and supplies a specific pattern image to the test optical system. An aerial image supply unit, and a measuring unit that measures a secondary image of the pattern re-imaged by the test optical system, wherein the measuring unit is any one of claims 1 to 4. An aberration measurement device, comprising the solid-state imaging device according to any one of the preceding claims.