JP2014143719A - Image sensor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image sensor substrate which improves mounting accuracy of semiconductor substrates by resolving limitations caused by arrangement positions of alignment marks provided in the semiconductor substrate for alignment .SOLUTION: An image sensor substrate includes: a semiconductor substrate 1 having a terminal part 4 and a circuit wiring pattern 1d; a photoelectric conversion section 2 which photoelectrically converts light; a driving circuit section 3 which outputs from the terminal part 4 an electric signal which was output from the photoelectric conversion section 2; a plurality of optical filters 5 which are selectively arranged on the photoelectric conversion section 2, and transmit light of different optical wavelengths; a light reflecting pattern part 6 which is formed in a predetermined region by laminating the plurality of optical filters 5 on the driving circuit section 3, except a predetermined region of the circuit wiring pattern 1d of the semiconductor substrate 1 or an open pattern 1d thereof in a region of the driving circuit section 3; a sensor substrate 7 having the semiconductor substrate 1 mounted thereon; and reference marks 7a provided on the sensor substrate 7. The semiconductor substrate 1 and the sensor substrate 7 are aligned by means of clearances between the reference marks 7a and the light reflecting pattern parts 6.

Description

  The present invention relates to an image sensor substrate for reading image information such as a copying machine, a facsimile machine, and an OCR, and more particularly to alignment of the image sensor substrate.

  In an apparatus for reading a document such as a copying machine or a facsimile, a contact image sensor is used as a small device. In the contact image sensor, an image sensor substrate on which a solid-state image sensor (sensor chip) such as a multi-chip mounting type CMOS is mounted is used. On a multi-chip type image sensor substrate, sensor chips are arranged at equal intervals while maintaining a constant pitch, and as the resolution of the sensor chip becomes higher, improvement in mounting accuracy is required. In order to improve mounting accuracy, for example, Japanese Patent Laid-Open No. 2000-182914, FIG. 1 (refer to Patent Document 1) discloses a cross shape of a smooth surface made of an aluminum layer 3 as an alignment mark for alignment of a semiconductor element. The mark main body portion 1 and the peripheral region of the mark main body portion 1 in which a stripe-shaped fine pattern 4 is formed by an aluminum layer 3 are disclosed.

  In FIG. 1c of Japanese Patent Laid-Open No. 5-183145 (see Patent Document 2), a semiconductor device is manufactured in which the light shielding film 13 is partially removed and the sensor light receiving unit 11 is opened, leaving a region to be shielded from light. A method is disclosed.

Japanese Unexamined Patent Publication No. 2000-182914 (FIG. 1) JP-A-5-183145 (FIG. 1)

  However, since the thing of patent document 1 has a large brightness | luminance difference with the reflected light from the mark main-body part 1 and the reflected light from the fine pattern 4 formation part of a peripheral region, it obtains the stable recognition by an image recognition apparatus. However, there is a problem that the arrangement position of the alignment mark is limited because it is necessary to arrange the fine pattern 4 in the peripheral region.

  Although the thing of patent document 2 uses the light shielding film 13 which shields light except the sensor light-receiving part 11, there is no description regarding the filter function of a light wavelength.

  An object of the present invention is to provide a substrate for an image sensor that can eliminate restrictions due to the position of alignment marks for alignment provided on a semiconductor substrate and improve the mounting accuracy between semiconductor substrates by using the alignment marks. To do.

  An image sensor substrate according to the present invention includes a semiconductor substrate having a terminal portion and a circuit wiring pattern to form a circuit, and a number of photoelectric conversions that are linearly provided in the longitudinal direction of the semiconductor substrate and photoelectrically convert light. A drive circuit unit provided between the photoelectric conversion unit and the terminal unit, which sequentially switches an electrical signal output from the photoelectric conversion unit and outputs the analog signal as an analog signal from the terminal unit, and the photoelectric conversion unit A plurality of optical filters having different optical wavelengths that are selectively applied to each of the conversion units and transmit light of a predetermined optical wavelength, and a circuit wiring pattern of the semiconductor substrate in the area of the drive circuit or the Except for a predetermined region of the open pattern, by laminating a plurality of the optical filters on the drive circuit unit, the light reflection pattern unit formed in the predetermined region, A sensor board on which a conductor board is placed, and a reference mark provided on the sensor board, and the semiconductor substrate and the sensor board are positioned at a distance between the reference mark and the light reflection pattern portion. is there.

  According to the image sensor substrate according to the present invention, there is an effect that the restriction due to the arrangement position of the alignment mark for alignment is eliminated, and the mounting accuracy between the semiconductor substrates can be improved by the alignment mark.

It is a top view of the semiconductor substrate part of the substrate for image sensors by Embodiment 1 of this invention. It is a top view of the semiconductor substrate part of the substrate for image sensors by Embodiment 1 of this invention. It is a figure explaining the arrangement | sequence of the photoelectric conversion part of the board | substrate for image sensors by Embodiment 1 of this invention. It is sectional drawing of the semiconductor substrate part of the substrate for image sensors by Embodiment 1 of this invention. It is a top view explaining the mounting method of the semiconductor substrate of the substrate for image sensors by Embodiment 1 of this invention. It is a partial enlarged plan view explaining the mounting method of the semiconductor substrate of the substrate for image sensors by Embodiment 1 of this invention. FIG. 7A is a diagram for explaining the relationship between the pattern of the optical filter applied to the semiconductor substrate 1 of the image sensor substrate according to Embodiment 1 of the present invention and the circuit wiring pattern of the semiconductor substrate. When the punching pattern is L-shaped, FIG. 7B shows the case where the punching pattern is circular. It is a top view of the semiconductor substrate part of the substrate for image sensors by Embodiment 2 of this invention. It is a figure explaining the arrangement | sequence of the photoelectric conversion part of the board | substrate for image sensors by Embodiment 2 of this invention. It is a top view of the semiconductor substrate part of the substrate for image sensors by Embodiment 3 of this invention. It is a top view explaining the mounting method of the semiconductor substrate of the substrate for image sensors by Embodiment 3 of this invention. It is a partial expanded plan view explaining the mounting method of the semiconductor substrate of the substrate for image sensors by Embodiment 3 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIG. FIG. 1 is a plan view of a semiconductor substrate portion of an image sensor substrate according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a semiconductor substrate using a silicon material or the like, and an area for receiving light on the surface, a circuit pattern using PMOS or NMOS, an input / output terminal pad, and the like are formed in a CMOS configuration. 2 is composed of a photodiode circuit (PD) or a transistor circuit (TR) on the semiconductor substrate 1, and a photoelectric conversion unit that accumulates received photoelectric charges and performs photoelectric conversion, and 3 indicates an electric signal photoelectrically converted by the photoelectric conversion unit 2. A driving circuit unit that obtains a sequential output of analog signals by sequentially switching with an analog switch via a latch circuit by a start signal input to the shift register circuit, 4 is a terminal unit that outputs the analog signal of the driving circuit unit 3 to the outside The input / output terminals (wire bond input / output pads) are electrically connected to the outside of the semiconductor substrate 1 by a wire bond process.

  FIG. 2 is a plan view of the semiconductor substrate portion of the image sensor substrate according to the first embodiment of the present invention. In FIG. 2, 5 denotes an optical filter (light shielding film) that shields light except a predetermined optical wavelength, and 6 denotes an extraction pattern (light reflection pattern portion) of the optical filter 5. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

  FIG. 3 is a diagram illustrating the arrangement of the photoelectric conversion units of the image sensor substrate according to the first embodiment of the present invention. In FIG. 3, 2r is a photoelectric conversion portion coated with a red filter using a gelatin material or the like (light receiving surface), 2g is a photoelectric conversion portion coated with a green filter using a gelatin material or the like on the surface (light receiving surface), 2b Is a photoelectric conversion portion in which a blue filter using a gelatin material or the like is coated on the surface (light receiving surface). The photoelectric conversion unit 2 is linearly arranged in the longitudinal direction in the order of a photoelectric conversion unit 2r mounted with a red filter, a photoelectric conversion unit 2g mounted with a green filter, and a photoelectric conversion unit 2b mounted with a blue filter. Arrange repeatedly. That is, optical filters 5r, 5g, and 5b (photoelectric conversion units 2r, 2g, and 2b) having different optical wavelengths are arranged in order for each photoelectric conversion unit 2, and a plurality of sets are repeatedly arranged with the arranged group as one set. .

  FIG. 4 is a cross-sectional view of the semiconductor substrate portion of the image sensor substrate according to the first embodiment of the present invention. In FIG. 4, 1a is a silicon substrate, 1b is a transparent protective film (lower insulating layer) that protects the active region of the semiconductor substrate 1, and 1c is a transparent protective film (upper insulating layer) that protects the upper circuit of the semiconductor substrate 1. ) 1d is a conductor pattern (circuit wiring pattern) using an aluminum material provided on the surface of the lower insulating layer 1b, 1e is a photodiode (PD), an analog switch, a latch, and a shift register that constitute the photoelectric conversion unit 2. These are electrodes (terminals) of a CMOS circuit constituting the drive circuit unit 3. An optical filter (red filter) 5r is applied to the surface of the photoelectric conversion unit 2r and not applied to the other photoelectric conversion unit 2, and 5g is applied to the surface of the photoelectric conversion unit 2g. An optical filter (green filter) 5b is applied to the surface of the photoelectric conversion unit 2b, and an optical filter (blue filter) is not applied to the other photoelectric conversion units 2.

  The optical filter 5 includes a driving circuit unit 3 disposed between the photoelectric conversion unit 2 arranged at one longitudinal end of the semiconductor substrate 1 and the terminal unit 4 arranged around the other longitudinal end. It is also applied to the area where it is. The optical filters 5r, 5g, and 5b in the region where the drive circuit unit 3 is disposed are stacked by overlapping three layers to form a light shielding film that shields light.

  In a color reading contact type image sensor, an optical filter is disposed on a light receiving surface of a photoelectric conversion unit constituted by a photodiode (PD) or the like for accumulating electric charges in order to identify an optical signal as color information. This optical filter is composed of, for example, red, green, and blue, and has different optical wavelengths for transmitting or blocking light. The red optical filter transmits or blocks a wavelength of about 640 nm. The green optical filter transmits or blocks a wavelength of about 525 nm. The blue optical filter transmits or blocks a wavelength of about 475 nm. In this Embodiment 1, these optical filters are arrange | positioned at the light-receiving surface of the photoelectric conversion part 2, and three types of optical filters are repeatedly arrange | positioned in the decided order. In addition, in order to shield visible light from areas other than the photoelectric conversion unit 2, the respective optical filters are stacked, and in the stacked areas, visible light is shielded when an optical filter that transmits a specific wavelength is used. .

  Next, the operation will be described. The light irradiated to the photoelectric conversion unit 2 transmits only a predetermined wavelength component by the optical filter 5, passes through the protective films 1b and 1c, and reaches the photodiode (PD). The light irradiated to the semiconductor substrate 1 generates carriers by its own energy. These carriers diffuse and move in the semiconductor and reach the region of the photoelectric conversion unit 2 composed of the PN junction. The reached carrier is photoelectrically converted by the photoelectric conversion unit 2, subjected to signal processing by the drive circuit unit 3, and taken out as an electric signal from the terminal unit 4.

  Light irradiated outside the region of the photoelectric conversion unit 2 is blocked by the stacked optical filter 5. The light irradiated to the region where the laminated optical filter 5 is not disposed is reflected by the circuit wiring pattern 1 d wired with an aluminum material formed on the surface of the protective film 1 b in the active region of the semiconductor substrate 1.

  FIG. 5 is a plan view for explaining a semiconductor substrate mounting method of the image sensor substrate according to the first embodiment of the present invention. In FIG. 5, 7 is a sensor substrate on which the semiconductor substrate 1 is placed, and 7 a is an alignment mark (reference mark) installed on the sensor substrate 7. In FIG. 5, the semiconductor substrates 1 are arranged at an equal pitch, and the photoelectric conversion units 2 are extended linearly. In the figure, the same reference numerals as those in FIG. 2 denote the same or corresponding parts.

  FIG. 6 is a partially enlarged plan view for explaining the mounting method of the semiconductor substrate of the image sensor substrate according to the first embodiment of the present invention. In FIG. 6, L1 and L2 indicate the separation pattern of the optical filter 5 and the separation distance between the reference mark 7a and the XY direction. L <b> 3 is a distance in the X direction between the extraction patterns 6 that are symmetrical with respect to the end side of the adjacent semiconductor substrate 1. 6, the same reference numerals as those in FIG. 5 denote the same or corresponding parts.

  Next, the extraction pattern 6 of the optical filter 5 will be described. The blank pattern 6 is provided to mount the semiconductor substrate 1 on the sensor substrate 7 with high accuracy, and is used as an alignment mark on the semiconductor substrate 1 side. A part of the circuit wiring pattern 1d or a floating island pattern (open pattern) 1d is provided in both end regions in the semiconductor substrate 1, and there are an L shape, an H shape, a cross shape, and the like. In addition, the unique shape portion of the circuit wiring pattern 1d may be substituted for the alignment mark.

  Next, mounting on the semiconductor substrate 1 will be described. The distance between the reference mark 7a provided on the sensor substrate 7 and the pattern that can be aligned with the circuit wiring pattern 1d of the semiconductor substrate 1 is recognized or detected and mounted. Mounting is performed with reference to the absolute coordinates of the extracted pattern 6 inside the semiconductor substrate 1 with reference to the reference mark 7 a arranged on the sensor substrate 7. This is called an absolute value correction method.

  As another mounting method, mounting is performed while correcting the position of the pixel position coordinate at the end of the semiconductor substrate 1 mounted in advance and the extraction pattern 6 of the semiconductor substrate 1 to be mounted from now on, which is mounted by the absolute value correction method. To do. This is called a relative value correction method.

  By using the relative value correction method, the gap between adjacent semiconductor substrates 1 can be corrected at a short distance (L3), so that the mounting accuracy is improved.

Next, the relationship between the blank pattern 6 and the circuit wiring pattern 1d will be described. FIG. 7 is a diagram for explaining the relationship between the extraction pattern 6 of the optical filter 5 applied to the semiconductor substrate 1 of the image sensor substrate and the circuit wiring pattern 1d of the semiconductor substrate 1 according to the first embodiment of the present invention. 7A shows a case where the punching pattern 6 is L-shaped, and FIG. 7B shows a case where the punching pattern 6 is circular. 7, the same reference numerals as those in FIG. 2 denote the same or corresponding parts.
In FIG. 7A, a partial region of the circuit wiring pattern 1 d is an L-shaped extraction pattern 6. In FIG. 7B, a partial region of the region where the circuit of the circuit wiring pattern 1 d is a floating island is a circular cut pattern 6.

  The circuit wiring pattern 1d that reflects light preferably uses a circuit wiring pattern 1d region of a shift register circuit or a latch circuit that forms a logic circuit, except for the floating island pattern 1d.

  As described above, according to the image sensor substrate according to the first embodiment, the extraction pattern 6 is formed in a part of the optical filter 5 in which the filters having different optical wavelengths are stacked, and the semiconductor that reflects the unnecessary light incident on the extraction pattern 6 is reflected. Since the light reflection pattern portion formed on the substrate 1 is provided, there is an effect that the restriction due to the position of the alignment mark for alignment can be eliminated, and the alignment mark can improve the mounting accuracy between the semiconductor substrates.

Embodiment 2. FIG.
FIG. 8 is a plan view of the semiconductor substrate portion of the image sensor substrate according to the second embodiment of the present invention. In FIG. 8, 20 indicates a photoelectric conversion unit, 50 indicates an optical filter, and 60 indicates an extraction pattern of the optical filter 50. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. FIG. 9 is a diagram for explaining the arrangement of the photoelectric conversion units of the image sensor substrate according to the second embodiment of the present invention. In FIG. 9, 20r is a photoelectric conversion unit coated with a red filter, 20g is a photoelectric conversion unit coated with a green filter, and 20b is a photoelectric conversion unit coated with a blue filter.

  The photoelectric conversion unit 20r mounted with a red filter, the photoelectric conversion unit 20g mounted with a green filter, and the photoelectric conversion unit 20b mounted with a blue filter are photoelectric conversion units 20 that are optical filters having different optical wavelengths in a direction orthogonal to the longitudinal direction. Are arranged in parallel. And it is set as the photoelectric conversion part 20 made into the optical filters 5 of the same optical wavelength over the longitudinal direction. Since other configurations are the same as those described in the first embodiment, description thereof will be omitted.

  In the first embodiment, the photoelectric conversion units 2 to which three types of filters 5 are applied in one row are arranged in a regular order. However, in the second embodiment, the photoelectric conversion units 20 are arranged in three rows. Also, three systems of drive circuit units are arranged, and filters 50 that transmit light of different optical wavelengths are arranged in the photoelectric conversion units 20 of the respective columns.

  As described above, according to the image sensor substrate according to the second embodiment, the extraction pattern 60 is formed in a part of the optical filter 50 in which the filters having different optical wavelengths are stacked, and the unnecessary light incident on the extraction pattern 60 is reflected. Since the light reflection pattern portion formed on the substrate 1 is provided, the restriction due to the arrangement position of the alignment mark for alignment is eliminated, and the alignment mark has the effect of improving the mounting accuracy between the semiconductor substrates and the same. A high-resolution image sensor substrate can be obtained by increasing the arrangement density of the photoelectric conversion units provided with the optical filters of wavelengths.

Embodiment 3 FIG.
FIG. 10 is a plan view of a semiconductor substrate portion of an image sensor substrate according to Embodiment 3 of the present invention. In FIG. 10, 51 is an optical filter, 61 is a removal pattern of the optical filter 51 arranged at the end. Reference numeral 62 denotes a removal pattern of the optical filter 51 disposed inside the end portion. In the figure, the same reference numerals as those in FIG. 2 denote the same or corresponding parts. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

FIG. 11 is a plan view for explaining a semiconductor substrate mounting method of an image sensor substrate according to the third embodiment of the present invention. In FIG. 11, 70 is a sensor substrate on which the semiconductor substrate 1 is placed, and 70 a is an alignment mark (reference mark) installed on the sensor substrate 70. In the figure, the same reference numerals as those in FIG. 2 denote the same or corresponding parts.

FIG. 12 is a partially enlarged plan view for explaining the mounting method of the semiconductor substrate of the image sensor substrate according to the first embodiment of the present invention. In FIG. 12, L4 indicates a distance in the X direction between the extraction pattern 61 of the optical filter 51 provided at the end of the semiconductor substrate 1 and the extraction pattern 62 of the optical filter 51 provided inside the end of the semiconductor substrate 1. 12, the same reference numerals as those in FIG. 10 denote the same or corresponding parts.

  Next, the operation will be described. In FIG. 11, the semiconductor substrates 1 are mounted on the sensor substrate 70 in a staggered arrangement. In the staggered mounting, the odd-numbered semiconductor substrates 1 and the even-numbered semiconductor substrates 1 are arranged on the sensor substrate 70 with reference to the reading line. The odd-numbered semiconductor substrates 1 and the even-numbered semiconductor substrates 1 are arranged with a certain overlap with each other. In other words, the photoelectric conversion unit 2 installed on the semiconductor substrate 1 is calculated from the number of overlapping pixels of the odd-numbered semiconductor substrate 1 and the even-numbered semiconductor substrate 1. Unlike a mounting method in which a gap is provided in a straight line, an overlap area of several pixels is provided, and an area corresponding to the gap generated between the semiconductor substrates 1 is provided to perform pixel interpolation.

  When mounting in a staggered arrangement, the semiconductor substrates 1 are arranged in a zigzag pattern at equal pitches and die-bonded in a straight line by a mechanical mounting device. At this time, the mounting is performed using the alignment marks 70 a provided on the sensor substrate 70 and the extraction patterns 61 and 62 provided on the semiconductor substrate 1. For example, the reference marks 70a are provided at both ends of the sensor substrate 70 on the reading line, and the blank pattern 61 of the odd-numbered semiconductor substrate 1 is recognized and die-bonded from the position of the reference mark 70a. Next, the die-bonding pattern 62 of the even-numbered semiconductor substrate 1 is recognized and die-bonded. Thereafter, die bonding is performed using the relative value correction method described in the first embodiment.

  As described above, according to the image sensor substrate according to the third embodiment, the extraction patterns 61 and 62 are formed on a part of the optical filter 51 in which filters having different optical wavelengths are stacked, and unnecessary light incident on the extraction pattern is reflected. Since the light reflection pattern portion formed on the semiconductor substrate 1 is provided, there is an effect that the restriction due to the position of the alignment mark for alignment can be eliminated and the mounting accuracy between the semiconductor substrates 1 can be improved by the alignment mark. At the same time, it is possible to mount the semiconductor substrates 1 arranged in a staggered manner with high accuracy by properly using the extraction patterns 61 and 62.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate 1a ... Silicon substrate 1b ... Protective film 1c ... Protective film 1d ... Conductor pattern (circuit wiring pattern) 1e ... Electrode 2 ... Photoelectric conversion part 2r ... Photoelectric with red filter applied Conversion unit 2g ·· Photoelectric conversion unit 2b coated with green filter ·· Photoelectric conversion unit 3 coated with blue filter ·· Drive circuit unit 4 ·· Terminal unit (input / output pad)
5. ・ Optical filter 5r ・ ・ Optical filter (red filter)
5g ・ ・ Optical filter (green filter)
5b ・ ・ Optical filter (blue filter)
6. ・ Punching pattern (light reflection pattern part)
7. Sensor board 7a Alignment mark (reference mark)
20. Photoelectric conversion unit 20r, photoelectric conversion unit 20g coated with red filter, photoelectric conversion unit 20b coated with green filter, photoelectric conversion unit 50 coated with blue filter, optical filter 51, optical filter 60 ..Punching pattern (light reflection pattern part)
61..Pattern pattern (light reflection pattern)
62 .. Removal pattern (light reflection pattern part)
70..Sensor board 70a..Alignment mark (reference mark)

Claims (1)

A semiconductor substrate having a terminal portion and a circuit wiring pattern to form a circuit;
A large number of photoelectric conversion units that are linearly provided in the longitudinal direction of the semiconductor substrate and photoelectrically convert light;
A drive circuit unit provided between the photoelectric conversion unit and the terminal unit, which sequentially switches the electrical signal output from the photoelectric conversion unit and outputs the analog signal from the terminal unit;
A plurality of optical filters having different optical wavelengths that are selectively applied to each of the photoelectric conversion units and transmit light of a predetermined optical wavelength;
A plurality of the optical filters are stacked on the drive circuit unit except for a predetermined region of the circuit board wiring line pattern or the open pattern of the semiconductor substrate in the drive circuit region, and formed in the predetermined region. A light reflection pattern portion;
A sensor substrate on which the semiconductor substrate is placed;
With a reference mark provided on this sensor board,
An image sensor substrate for positioning the semiconductor substrate and the sensor substrate at a distance between the reference mark and the light reflection pattern portion.

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