JP5061579B2 - Solid-state imaging device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof, and more particularly, to a solid-state imaging device capable of keeping a distance between a wafer and a glass substrate constant during manufacturing and a manufacturing method thereof.

  In recent years, digital cameras and video cameras using solid-state imaging devices such as CCDs and CMOSs have become widespread, but a technology for further downsizing the solid-state imaging devices using a CSP (chip size package) system has been developed. . Such a small solid-state imaging device is suitable for being incorporated in an electronic device that is desired to be small, light, and thin, such as a mobile phone.

  A small solid-state image sensor is placed opposite to each other, with a spacer for maintaining a certain distance between the solid-state image sensor chip with a large number of microlenses on the light receiving surface and an infrared cut transparent glass plate. The peripheral edge of the gap is sealed with an adhesive (for example, see Patent Document 1).

  A small solid-state image sensor configured in this way is obtained by bonding a solid-state image sensor wafer on which a solid-state image sensor chip is multifaceted and an infrared cut transparent glass substrate with a spacer interposed therebetween, and then solid-state image sensor It is manufactured by polishing the back surface of the wafer to a thickness of about 30 to 100 μm and then cutting each solid-state imaging device chip.

In this case, the distance between the solid-state imaging device wafer and the infrared cut transparent glass substrate is defined by the height of the spacer, and it is necessary to make this uniform over the entire surface of the wafer having a diameter of 20 to 30 cm. However, in the conventional spacer, when pressure is applied from above the infrared cut transparent glass substrate at the time of bonding, there is a problem that it is easily compressed and the distance cannot be maintained uniformly over the entire wafer surface.
JP 2002-329852 A

  The present invention has been made under the circumstances as described above, and has sufficient strength even when a large pressure is applied in the manufacturing process, and maintains a uniform distance between the solid-state imaging device wafer and the glass substrate. An object of the present invention is to provide a solid-state imaging device having such a structure and a manufacturing method thereof.

In order to solve the above-described problems, a first aspect of the present invention is a solid-state image sensor chip having a microlens, a transparent plate disposed to face a light receiving surface of the solid-state image sensor chip, and the solid-state image sensor. In order to keep the distance between the chip and the transparent plate constant, a spacer arranged in a frame shape around the light receiving surface of the solid-state image sensor chip and the periphery of the gap between the solid-state image sensor chip and the transparent plate are sealed In the solid-state imaging device including the adhesive layer, the spacer includes a plurality of partition walls including a partition wall higher than the microlens formed on the solid-state image sensor chip and another partition wall higher than the partition wall. A solid-state imaging device is provided.

  In such a solid-state imaging device, the spacer can be composed of three partition walls.

  According to a second aspect of the present invention, there is provided a manufacturing method of the above-described solid-state imaging device, wherein each of the solid-state imaging element wafers provided with a plurality of solid-state imaging element chips and at least one of the transparent substrates is an individual solid-state imaging element. Forming a plurality of frame-shaped partition walls having different heights constituting a spacer at a peripheral portion of the chip or a position corresponding thereto, the solid-state imaging device wafer and a transparent substrate interposed between the plurality of partition walls In a state where the solid-state image pickup device chip is bonded to each other through the adhesive layer provided on the periphery of each solid-state image pickup device chip on the wafer, and the step of cutting the bonded structure for each solid-state image pickup device chip. A method of manufacturing a solid-state imaging device is provided.

  In the manufacturing method of such a solid-state imaging device manufacturing method, the plurality of partition walls constituting the spacer are constituted by one partition wall having a high height and two partition walls having a low height provided on both sides thereof. be able to.

  Moreover, in the manufacturing method of the above solid-state imaging device and its manufacturing method, a spacer can be comprised with at least 1 sort (s) of resin chosen from the group which consists of a polyimide resin, an epoxy resin, and an epoxy-acrylate resin.

  According to the present invention, by configuring the spacer with a plurality of partition walls, particularly with a plurality of partition walls having different heights, even with a large pressure when the solid-state imaging device wafer and the transparent substrate are bonded in the manufacturing process of the solid-state imaging device, Since the two kinds of spacers having different heights support in two stages, the distance between the solid-state imaging device wafer of the spacer and the transparent substrate can be uniformly maintained over the entire surface.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a cross-sectional view showing a solid-state imaging device according to an embodiment of the present invention. In FIG. 1, a plurality of microlenses 2 are provided on the upper surface (light receiving surface) of the solid-state imaging device chip 1, and a transparent plate, that is, an infrared cut transparent glass plate 3 is opposed to the microlenses 2. Has been placed. As the solid-state image sensor chip 1, a CCD or CMOS sensor can be used.

  Between the solid-state imaging device chip 1 and the infrared cut transparent glass plate 3, a spacer 4 composed of three frame-shaped partitions is interposed, and the distance between the two is kept constant. The periphery of the gap between the solid-state imaging device chip 1 and the infrared cut transparent glass plate 3 is sealed with an adhesive layer 5 formed by curing an ultraviolet curable resin.

  An electrode pad (not shown) of the solid-state image sensor is provided on the periphery of the upper surface of the solid-state image sensor chip 1, and a back electrode (not shown) is provided on the periphery of the bottom surface. In order to connect the back surface electrode, a side wall wiring layer 6 extending from the upper surface periphery of the solid-state imaging device chip 1 through the side surface to the bottom surface periphery is formed. Further, external connection bumps 7 are formed on the side wall peripheral wiring layer 6 in the periphery of the bottom surface of the solid-state imaging device chip 1.

  The side part and the bottom part of such a structure are covered with an insulating layer 8 made of a solder resist.

  The solid-state imaging device configured as described above is manufactured by the following manufacturing process.

  That is, first, a solid-state image sensor wafer provided with a plurality of solid-state image sensor chips and a plurality of microlenses formed on the upper surface thereof, and a transparent glass substrate having the same size as this wafer are prepared. Next, a plurality of partition walls having different heights are formed on one or both of the solid-state image sensor wafer and the transparent glass substrate at the peripheral portion of each solid-state image sensor chip or a position corresponding thereto. An example is shown in FIG.

  That is, FIG. 2 is an enlarged view of a portion where a spacer is formed in a state in which the solid-state imaging device wafer 11 and the transparent substrate 12 are arranged to face each other for bonding. In FIG. 2, a first partition 13 having a high height is formed on the lower surface of the transparent substrate 12, and the first partition 13 is positioned on both sides of the first partition 13 on the upper surface of the solid-state imaging device wafer 11. Second and third partition walls 14 and 15 having a height lower than that of the partition wall 13 are provided. The first to third partition walls constitute the spacer 4 shown in FIG.

  The height of the first partition wall 13 is, for example, 50 to 120 μm, and the width is, for example, 70 to 150 μm. The height of the second and third partition walls 14 and 15 is higher than the height of the microlens 2 so that the microlens 2 does not come into contact with the transparent glass substrate and is damaged, for example, 40 to 100 μm. And the width is, for example, 70 to 150 μm.

  The partition wall can be formed by patterning the photosensitive resin composition by photolithography. As the constituent resin, polyimide resin, epoxy resin, epoxy-acrylate resin, or the like can be used.

  Next, an adhesive layer made of an ultraviolet curable resin or the like is applied to a position outside the partition wall of the solid-state imaging device wafer. And a solid-state image sensor wafer and a transparent glass substrate are bonded together.

  At the time of bonding, a large pressure is applied to the transparent glass substrate. As a result, the first partition wall 13 having a high height is compressed, the height is reduced, and the space between the solid-state imaging device wafer and the transparent substrate is reduced. The distance decreases. However, due to the presence of the second and third partition walls 14 and 15 on both sides, the distance between the solid-state imaging device wafer and the transparent substrate does not decrease any more, and is maintained uniformly over the entire surface. In other words, the spacer made up of the compressed first partition wall 13 having a predetermined repulsive force and the second and third partition walls 14 and 15 having low heights on both sides of the first partition wall 13 can be applied even under a large pressure at the time of bonding. The distance between the solid-state imaging device wafer and the transparent substrate can be maintained uniformly over the entire surface.

  In addition, after bonding, the distance between a solid-state image sensor wafer and a transparent substrate is fixed by hardening | curing an adhesive bond layer by irradiation of an ultraviolet-ray.

  After that, the bonded structure is cut for each solid-state imaging device chip at the position of the adhesive layer by a dicing apparatus, and the insulating layer 8 including the sidewall wiring layer 6 and the solder resist is formed. By forming the external connection bumps 7 through the formed holes, a solid-state imaging device including one solid-state imaging device chip as shown in FIG. 1 is manufactured.

  In the example shown in FIG. 2, the first partition 13 having a high height is provided on the lower surface of the transparent substrate 12, and the second and third partitions having a lower height than the first partition 13 are provided on the upper surface of the solid-state imaging device wafer 11. Although 14 and 15 are provided, the present invention is not limited to this, and various partition arrangements can be employed.

  For example, in FIG. 3, the first partition 13 having a high height is provided on the upper surface of the solid-state imaging device wafer 11, and the second and third partitions 14 and 15 having a lower height than the first partition 13 are provided on the transparent substrate 12. The example provided in the lower surface of is shown. FIG. 4 shows an example in which the first partition 13 having a high height and the second and third partitions 14 and 15 having a low height are all provided on the upper surface of the solid-state imaging device wafer 11.

  In the above example, a high partition wall is provided at the center and low partition walls are provided on both sides thereof. However, the present invention is not limited to this, and a high partition wall is adjacent to either side. It is also possible to provide two partition walls having a low height. However, when there are three partition walls, it is desirable to provide two partition walls having a low height in order to reliably keep the distance between the solid-state imaging device wafer and the transparent substrate constant.

  The number of partition walls is not limited to three, but may be four or more, or may be two in some cases.

It is sectional drawing which shows the solid-state imaging device which concerns on one Embodiment of this invention. It is a figure which shows arrangement | positioning of the three partition walls which comprise a spacer in the manufacturing process of the solid-state imaging device shown in FIG. It is a figure which shows the other example of arrangement | positioning of the three partition walls which comprise a spacer. It is a figure which shows the other example of arrangement | positioning of the three partition walls which comprise a spacer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Solid-state image sensor chip, 2 ... Micro lens, 3 ... Infrared cut transparent glass plate, 4 ... Spacer, 5 ... Adhesive layer, 6 ... Wiring layer around a side wall, 7 ... Bump for external connection, 8 ... Insulating layer, DESCRIPTION OF SYMBOLS 11 ... Solid-state image sensor wafer, 12 ... Transparent substrate, 13 ... 1st partition, 14 ... 2nd partition, 15 ... 3rd partition.

Claims (6)

The solid-state imaging device chip having a microlens, the transparent plate disposed to face the light receiving surface of the solid-state imaging device chip, and the solid-state imaging in order to keep a constant distance between the solid-state imaging device chip and the transparent plate a spacer arranged like a frame on the periphery of the light receiving surface of the element chip, in the solid-state imaging device including an adhesive layer for sealing the periphery of the air gap of the solid-state imaging device chip and the transparent plates, the spacer, the A solid-state imaging device comprising a plurality of partition walls including a partition wall higher than a microlens formed on a solid-state image sensor chip and another partition wall higher than the partition wall .   The solid-state imaging device according to claim 1, wherein the spacer includes three partition walls.   3. The solid-state imaging device according to claim 2, wherein the plurality of partition walls constituting the spacer include a partition wall having a high height and two partition walls having a low height provided on both sides thereof.   The solid-state imaging device according to claim 1, wherein the spacer is made of at least one resin selected from the group consisting of a polyimide resin, an epoxy resin, and an epoxy-acrylate resin. The manufacturing method of the solid-state imaging device according to claim 1, wherein at least one of a solid-state imaging device wafer provided with a plurality of solid-state imaging device chips and a transparent substrate, Forming a plurality of frame-shaped partition walls having different heights constituting the spacer at positions corresponding thereto;
A step of bonding the solid-state imaging element wafer and the transparent substrate through an adhesive layer provided on a peripheral edge of each solid-state imaging element chip on the wafer with the plurality of partition walls interposed therebetween. And a step of cutting the bonded structure for each solid-state imaging device chip. 6. The method of manufacturing a solid-state imaging device according to claim 5 , wherein the spacer is made of at least one resin selected from the group consisting of polyimide resin, epoxy resin, and epoxy-acrylate resin.

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