JP2005260111A - Method for manufacturing image sensor, image sensor, and package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an accurate image sensor having a sensor chip accurately mounted on a package. <P>SOLUTION: A method for manufacturing an image sensor includes steps of preparing a package board having a suction hole in its internal bottom surface and having an adhesive coated on the internal bottom surface, mounting a sensor chip on the adhesive, sucking the sensor chip through the suction hole and fixing the sensor chip to the internal bottom surface, and curing the adhesive to adhere the sensor chip to the internal bottom surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an image sensor and its structure, and more particularly to a method for manufacturing a multi-chip image sensor and its structure.

  In an image sensor, one or more sensor chips are arranged in a package. However, in order to suppress distortion of an image obtained from the image sensor and a decrease in resolution, the sensor chip needs to be arranged on the package substrate with high accuracy. .

For example, in a multi-chip image sensor, a recess having a size substantially the same as that of the sensor chip is provided at a position where the sensor chip is disposed inside the package, and the sensor chip is fitted into the recess and bonded with a resin. Thereby, the sensor chip is fixed at an accurate position (for example, Patent Document 1).
JP-A-5-75788

Such a mounting method has a problem that a manufacturing process for forming a recess in the package is separately required, resulting in an increase in manufacturing cost.
In addition, as the pixel pitch of the image sensor is reduced, there is a problem in that the displacement and inclination of the sensor chip in the recess also cause image distortion. In particular, when the sensor chip is chipped by chipping, the position of the sensor chip in the recess is greatly displaced.

  Accordingly, an object of the present invention is to provide an image sensor manufacturing method for mounting a sensor chip on a package with high accuracy, and an image sensor manufactured by such a method.

  The present invention includes a step of preparing a package substrate having an adsorption hole on the inner bottom surface and an adhesive applied to the inner bottom surface, and a placement step of placing the sensor chip on the adhesive so as to cover the adsorption hole And a suction step of sucking the sensor chip through the suction hole and fixing the sensor chip to the inner bottom surface, and a step of curing the adhesive and bonding the sensor chip to the inner bottom surface. It is a manufacturing method of a sensor.

  The present invention also provides a package substrate having a suction hole penetrating the inner bottom surface, a sensor chip fixed to the inner bottom surface with an adhesive so as to cover the suction hole, and a package substrate so as to cover the sensor chip. The image sensor is also characterized in that the suction hole is arranged point-symmetrically with respect to the center of gravity of the sensor chip when viewed from the normal direction of the inner bottom surface.

  In the method of manufacturing the image sensor according to the present invention, the sensor chip can be arranged without causing a positional shift or an inclination.

  In addition, the image sensor according to the present invention can obtain an image with high accuracy and high resolution.

Embodiment 1 FIG.
FIG. 1 is a top view of the linear sensor according to the present embodiment, the whole being represented by 100. 2 is a cross-sectional view of the linear sensor 100 of FIG. 1 when viewed in the II direction.

  The linear sensor 100 includes a package substrate 1. The package substrate 1 is made of, for example, ceramic and includes a die pad portion 1a on which the sensor chip 2 is mounted and a side wall portion 1b provided around the die pad portion 1a. A step portion 1c is provided inside the side wall portion 1b.

The die pad portion 1a of the package substrate 1 is provided with a suction hole 3 penetrating to the back surface (the lower surface in FIG. 2) of the package substrate 1. Each suction hole 3 has substantially the same shape, and the sensor chip is sucked through the suction hole 3 as described later. The suction is performed under the condition that the center of the suction force for sucking the sensor chip 2 and the center of gravity of the sensor chip 2 (here, the intersection of the diagonal lines of the sensor chip 2) are substantially the same.
In addition, as long as this condition is satisfied, the position, shape, and suction force of the suction hole 3 may be changed.

  As shown in FIG. 1, in the linear sensor 100, the sensor chip 2 will be mounted in a point-symmetrical position with respect to the center of the sensor chip area 2 a (corresponding to the center of gravity of the sensor chip 2) in the future. Adsorption holes 3 are provided. The suction force from each suction hole 3 is substantially the same.

  In addition, an adhesive 4 for bonding the sensor chip 2 is provided in the sensor chip region 2a. For the adhesive 4, for example, a thermosetting epoxy resin is used.

  Although three sensor chips 2 are finally mounted on the die pad portion 1a, only one sensor chip 2 is described here. A sensor chip region 2a indicated by a broken line is a position where the remaining two sensor chips are mounted.

  A predetermined wiring is performed on the sensor chip 2 by a bonding wire (not shown). Further, a lid (not shown) is placed on the stepped portion 1c, and the sensor chip 2 is covered. A cover part consists of glass or a germanium window, for example.

  The sensor chip 2 may be a chip such as a MOS or CMD in addition to a CCD chip.

Next, a method for manufacturing the linear sensor 100 will be described with reference to FIGS.
In such a manufacturing process, first, the package substrate 1 is prepared. As described above, the package substrate 1 includes the die pad portion 1a that is the inner bottom surface and the side wall portion 1b that surrounds the die pad portion 1a. Further, the side wall portion 1b is provided with the stepped portion 1c. A suction hole 3 is formed in the package substrate 1 in advance. Moreover, the adhesive 4 is also applied.

Next, as shown in FIG. 2, the package substrate 1 is placed on a table 150. The stage 150 is provided with exhaust lines 151 and 152. The suction hole 3 of the package substrate 1 is provided at a position corresponding to the end of the exhaust line 152, and the exhaust line 152 sucks the sensor chip 2 through the suction hole 3. Specifically, the die pad portion 1a is provided with an alignment mark (not shown), and the sensor chip 2 is arranged so as to meet the alignment mark.
Further, the back surface of the package substrate 1 is sucked by the exhaust line 151, and the package substrate 1 is fixed on the table 150.

  Next, the sensor chip 2 is held by, for example, the manipulator 153 and carried and placed on the sensor chip region 2a. After mounting, the back surface of the sensor chip 2 is sucked by the exhaust line 152 through the suction hole 3, and the sensor chip is fixed to the sensor chip region 2a of the die pad portion 1a. In this way, the three sensor chips 2 are each fixed.

Next, for example, by heating to about 150 ° C., the adhesive 4 made of an epoxy resin is cured, and the sensor chip 2 is fixed on the die pad portion 1a. The table 150 preferably includes a heater for heating.
In such a bonding process, even if the adhesive 3 is fluidized by heating, the package substrate 1 and the sensor chip 2 are sucked and fixed through the suction holes 3 and thus deviate or tilt from the sensor chip region 2a. There is nothing.

  Finally, after removing the package substrate 1 from the base 150 and performing wire bonding or the like, a lid (not shown) is placed on the stepped portion 1c. Thereby, the image sensor 100 including the three sensor chips 3 is completed.

  In the image sensor 100 according to the present embodiment, the displacement and inclination of the sensor chip 2 can be almost eliminated, and the sensor chip 2 can be arranged with high accuracy. In particular, the position of the sensor chip 2 can be arranged with an accuracy of only an arrangement error by the manipulator 153.

  As a result, it is possible to prevent image distortion caused by the positional deviation or inclination of the sensor chip 2. In addition, in a multi-chip type image sensor including a plurality of sensor chips 2, adjacent sensor chips 2 can be arranged with high accuracy, and image disturbance and resolution reduction at the connecting surface can be minimized.

In the first embodiment and the second to seventh embodiments described below, the image sensor includes both a line sensor and an area sensor.
The structure of the image sensor includes both a one-chip type in which only one sensor chip is mounted and a multi-chip type in which a plurality of chips are mounted.

Embodiment 2. FIG.
FIG. 3 is a top view of the linear sensor according to the present embodiment, indicated as a whole by 200. 4 is a cross-sectional view of the linear sensor 100 of FIG. 3 when viewed in the III-III direction.

  The linear sensor 200 includes a package substrate 11 made of, for example, ceramic. The package substrate 11 has a die pad portion 11a on which the sensor chip 12 is mounted and a side wall portion 11b provided around the die pad portion 11a. Further, a step portion 11c is provided inside the side wall portion 11b.

  A suction hole 13 is provided in the die pad portion 11 a of the package substrate 11. The suction hole 13 is provided with a relatively large opening in the approximate center of each sensor chip region 12a. The suction from the suction hole 13 is performed under the condition that the center of the suction force for sucking the sensor chip 12 is substantially the same as the center of gravity of the sensor chip 12.

  The sensor chip region 12a is provided with an adhesive 14 made of, for example, an epoxy resin.

  In the linear sensor 200, after the package substrate 11 is mounted on the table 160 provided with the heater 161, the manipulator 163 passes through the suction hole 13 and holds the sensor chip 12 from the back surface. After the sensor chip 12 is placed at a predetermined position using the manipulator 163, the sensor chip 12 is sucked and fixed by the vacuum line 162 through the suction hole 13.

  In such a state, the adhesive 161 is heated and cured by the heater 161, and the sensor chip 12 is fixed to the die pad portion 11a.

  In particular, when the sensor chip 12 is a chip that cannot touch the chip surface, such as a MEMS (Mechanical Electro Micro System) sensor, the manipulator 163 can be used to hold the sensor chip 12 from the back surface.

  As described above, in the sensor chip 200 according to the present embodiment, the sensor chip 12 can be arranged with high accuracy, and image disturbance and the like can be prevented. In particular, in a MEMS sensor or the like, damage to the sensor during assembly can be prevented.

Embodiment 3 FIG.
FIG. 5 is a cross-sectional view of the linear sensor according to the third embodiment, indicated as a whole by 250, and is a cross-sectional view seen in the III-III direction shown in FIG.

  The linear sensor 250 includes a package substrate 21 made of, for example, ceramic, and the package substrate 21 has a die pad portion 21a and a side wall portion 21b. Further, a step portion 21c is provided inside the side wall portion 21b.

  In the linear sensor 250, similarly to the linear sensor 200 described above, the suction hole 23 having a relatively large opening is provided, and the sensor chip 22 is sucked and fixed from the suction hole 23 while the sensor chip 22 is mounted on the package substrate 21. Secure to.

  Further, the suction hole 23 is filled with an adhesive 25 having high thermal conductivity such as silver paste, and a heat sink 26 is attached to the back surface of the sensor chip 22. The adhesive 25 is preferably made of a material that does not have high hardness in order to alleviate the occurrence of strain due to the difference in expansion coefficient between the sensor chip 22 and the heat sink 26. Instead of silver paste, silicon grease or indium may be used. The heat sink 26 is made of, for example, aluminum.

  Here, the heat sink 26 is attached using the suction hole 23 having a large opening, but the heat sink 26 may be attached by filling the plurality of holes arranged in a grid with the adhesive 25.

  As described above, in the image sensor 250 according to the present embodiment, the sensor chip 22 can be arranged with high accuracy, and image disturbance and the like can be prevented. Moreover, when using the sensor chip 22 which needs cooling like an infrared sensor, the sensor chip 22 can be cooled efficiently.

Embodiment 4 FIG.
FIG. 6 is a top view of a part of the image sensor according to the fourth embodiment, the whole being represented by 300. The package substrate 31 includes a die pad part 31a, a side wall part 31b, and a step part 31c.

  Two suction holes 33 are provided in the sensor chip region 32 where the sensor chip will be placed in the future. The suction holes 33 are arranged so as to be substantially point-symmetric with respect to the center point of the sensor chip region 32. Adhesives 34 are provided between and on both sides of the suction holes 33.

  By arranging the suction hole 33 and the adhesive 34, the center of the suction force for sucking the sensor chip and the center of gravity of the sensor chip are substantially the same, and the sensor chip can be sucked without being tilted.

Embodiment 5 FIG.
FIG. 7 is a top view of a part of the image sensor according to the fifth embodiment, the whole being represented by 400. The package substrate 41 includes a die pad part 41a, a side wall part 41b, and a step part 41c.

  A sensor chip region 42 where a sensor chip will be placed in the future is provided with a suction hole 43 having a relatively large opening at the center. The substantially circular suction hole 43 is arranged so that the center thereof is the center of the sensor chip region. An adhesive 44 is provided on both sides of the suction hole 43.

  By arranging the suction hole 43 and the adhesive 44, the center of the suction force for sucking the sensor chip and the center of gravity of the sensor chip are substantially the same, and the sensor chip can be sucked without being tilted. Further, the sensor chip can be held from the back surface by the manipulator 45 through the suction hole 43.

Embodiment 6 FIG.
FIG. 8 is a top view of a part of the image sensor according to the sixth embodiment, which is generally indicated by 500. The package substrate 51 includes a die pad part 51a, a side wall part 51b, and a step part 51c.

  In the sensor chip region 52 where the sensor chip will be placed in the future, a substantially rectangular suction hole 53 having a relatively large opening is provided in the center. An adhesive 54 is annularly provided around the suction hole 53 so as to surround the suction hole 53. The suction hole 53 is arranged so that the center thereof is the center of the sensor chip region 52.

By arranging the suction hole 53 and the adhesive 54, the center of the suction force for sucking the sensor chip and the center of gravity of the sensor chip are substantially the same, and the sensor chip can be sucked without being tilted.
Further, the sensor chip can be held from the back surface by the manipulator 55 through the suction hole 53.

Embodiment 7 FIG.
FIG. 9 is a top view of a part of the image sensor according to the seventh embodiment, the whole being represented by 600. The package substrate 61 includes a die pad portion 61a, a side wall portion 61b, and a step portion 61c.

  In the sensor chip area 62 where the sensor chip will be mounted in the future, an adhesive 64 is provided in a substantially rectangular area at the center. Around the periphery, four suction holes 63 are provided at symmetrical positions with the adhesive 64 in between.

  By arranging the suction hole 63 and the adhesive 64, the center of the suction force for sucking the sensor chip and the center of gravity of the sensor chip become substantially the same, and the sensor chip can be sucked without being tilted.

It is a top view of the image sensor concerning Embodiment 1 of the present invention. It is sectional drawing of the image sensor concerning Embodiment 1 of this invention. It is a top view of the image sensor concerning Embodiment 2 of this invention. It is sectional drawing of the image sensor concerning Embodiment 2 of this invention. It is sectional drawing of the image sensor concerning Embodiment 3 of this invention. It is a top view of the image sensor concerning Embodiment 4 of this invention. It is a top view of the image sensor concerning Embodiment 5 of this invention. It is a top view of the image sensor concerning Embodiment 6 of this invention. It is a top view of the image sensor concerning Embodiment 7 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Package board | substrate, 1a Die pad part, 1b Side wall part, 1c Step part, 2 Sensor chip, 3 Adsorption hole, 4 Adhesive, 100 Image sensors, 150 units, 151, 152 Exhaust line, 153 Manipulator.

Claims (13)

A step of preparing a package substrate having an adsorption hole on the inner bottom surface and an adhesive applied to the inner bottom surface;
A mounting step of mounting a sensor chip on the adhesive so as to cover the suction hole;
A suction step of sucking the sensor chip through the suction hole and fixing the sensor chip to the inner bottom surface;
Curing the adhesive and adhering the sensor chip to the inner bottom surface.   The placing step is a step of placing the sensor chip such that the suction hole is point-symmetric with respect to the center of gravity of the sensor chip when viewed from the normal direction of the inner bottom surface. The manufacturing method of Claim 1 characterized by the above-mentioned.   The manufacturing method according to claim 1, wherein the placing step is a step of holding the sensor chip from the back surface with a manipulator passing through the suction hole and placing the sensor chip on the adhesive.   The manufacturing method according to claim 1, wherein the placing step is a step of placing a plurality of sensor chips sequentially.   The manufacturing method according to claim 1, wherein the suction step is a step of sucking the sensor chip so that a center of the suction force acting on the sensor chip substantially coincides with a center of gravity of the sensor chip. Method.   The manufacturing method according to claim 1, wherein the suction step is a step of exhausting with a vacuum line through the suction hole.   The manufacturing method according to claim 1, further comprising a step of filling the suction hole with an adhesive and adhering a heat sink to the package substrate with the adhesive. A package substrate having a suction hole penetrating the inner bottom surface;
A sensor chip fixed to the inner bottom surface with an adhesive so as to cover the suction hole;
A lid placed on the package substrate so as to cover the sensor chip,
An image sensor, wherein the suction hole is arranged point-symmetrically with respect to the center of gravity of the sensor chip when viewed from the normal direction of the inner bottom surface.   The image sensor according to claim 8, wherein the center of gravity is an intersection of diagonal lines of the sensor chip.   The image sensor according to claim 8, wherein a plurality of sensor chips are fixed to the inner bottom surface.   The image sensor according to claim 8, further comprising: an adhesive filled in the suction hole; and a heat sink adhered to the package substrate with the adhesive.   A package comprising a sensor chip region on which a sensor chip is placed on an inner bottom surface, and a suction hole penetrating the inner bottom surface is provided in the sensor chip region.   The package according to claim 12, wherein the sensor chip area is substantially rectangular, and the suction holes are arranged point-symmetrically with respect to the intersection of diagonal lines of the sensor chip area.

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