This application claims priority under 35 USC 119 from Japanese Patent Application No. 2008-200010 filed on Aug. 1, 2008, the disclosure of which is incorporated by reference herein.
1. Technical Field
The present invention relates to a semiconductor device and to a fabrication method thereof. In particular the present invention relates to a semiconductor device structure having a semiconductor chip, such as a sensor module, and a protection glass.
2. Related Art
Existing known semiconductor devices having a semiconductor chip, such as a sensor module, and a protection glass include: a structure with a light blocking film formed on the side surfaces of an optical member provided on microlenses of a semiconductor chip (see Japanese Patent Application Laid-Open (JP-A) No. 2007-142058); a structure having a covering layer formed on a semiconductor chip having a circuit portion including a photoreceptor element, with a sealing resin formed to the whole of the semiconductor chip and on the side surfaces of the covering layer (see JP-A No. 2004-363380); and a solid state image capture device structure of a wafer-level chip sized package provided with a cover glass, supported with interposed spacers, for covering and protecting a photoreceptor portion of an image sensor chip, and with penetrating wires penetrating through the image sensor chip (see JP-A No. 2007-184680).
In the technology of JP-A No. 2007-142058 a light blocking film is provided for each of the individual optical members, and each of the individual optical members is adhered to each individual semiconductor chip one at a time, consequently this leads to many manufacturing processes for each image capture element, and a structure enabling the elimination of processing is desired.
In the technology of JP-A No. 2004-363380 after making external terminals of the back surface of the semiconductor chip in high pillar shapes, a sealing layer is formed covering the back surface and side surfaces of the semiconductor device, and bump electrodes are formed on top of the external terminals after the sealing layer has been polished, leading to a semiconductor device that is thick overall. In addition, various processes are added in order to lead the bump electrodes from the pillar shaped external terminals, giving rise to many manufacturing processes. A thin semiconductor device is therefore desired, and a structure enabling a reduction in processing is also desired. Cutting must be made in the dicing process with a blade appropriate for both a glass covering layer and a semiconductor wafer (referred to sometimes below simply as wafer), with there being fewer options for blade choice. Also, in comparison to when a blade appropriate to a covering layer is used, with a blade appropriate for both materials there is concern of breakage and defects etc. occurring at the cut face of the covering layer and also of affecting the top surface of the covering layer onto which light is incident. When the side surfaces of a semiconductor device are cut at an angle this also limits the yield of semiconductor devices obtained from one semiconductor wafer.
In the solid state image capture device of JP-A No. 2007-184680, an anti-reflection layer is formed to the back surface of an image sensor to prevent reflection of light that has been transmitted through the image sensor during image capture, and incidence thereof onto the photoreceptor. However, since light enters from the side surfaces of the above cover glass, there is the problem that desired characteristics are not obtained. In addition, the cover glass and the semiconductor wafer are partitioned using dicing technology, requiring a wide cut width by a blade suited to both materials, and therefore the scribe line width of the semiconductor chip needs to be set wide, with an issue being that the effective number of elements on a semiconductor wafer is reduced. In addition, technical problems arise, such as defects to corner portions of the cover glass during dicing and defects readily occurring during handling, reducing the yield rate, or dicing stress acting on a spacer bonding portion interface reducing reliability such as water resistance.
The present invention is made in consideration of the above technical problems and provides a semiconductor device with suppressed number of fabrication processes and obtaining raised yields of the semiconductor device, and a fabrication method thereof.
According to an aspect of the present invention, there is provided a semiconductor device including:
a semiconductor chip having a penetrating electrode penetrating through from a first main surface of the semiconductor chip to a second main surface on the opposite side thereof, a photoreceptor portion formed on the first main surface, and a first wire at a periphery of the photoreceptor portion;
a light transmitting chip adhered to the first main surface at the periphery of the light transmitting chip, with a bonding layer interposed between the light transmitting chip and the first main surface, the light transmitting chip covering the light transmitting chip; and
a light blocking resin layer formed only on the side surfaces of the light transmitting chip and the bonding layer.
Further, according to another aspect of the present invention, there is provided a semiconductor device fabrication method including:
forming a bonded body from a semiconductor wafer and a light transmitting substrate, the semiconductor wafer having a plurality of circuit regions thereon, the circuit regions each including a penetrating electrode penetrating through from a first main surface of the semiconductor wafer to a second main surface on the opposite side thereof, a photoreceptor portion formed on the first main surface, and a first wire at a periphery of the photoreceptor portion, and the light transmitting substrate adhered at the periphery of each of the circuit regions with a bonding layer interposed therebetween, and the light transmitting substrate covering the photoreceptor portion;
forming a groove in the light transmitting substrate of the bonded body so as to reach the bonding layer, and filling the groove with light blocking resin to form a light blocking resin layer;
severing the light blocking resin layer with a width narrower than the groove width, dividing the bonded body into a plurality of semiconductor chips and respective light transmitting chips joined by a bonding layer, leaving the light blocking resin layer remaining formed only on the side surfaces of the light transmitting chip and the bonding layer.
In the another aspect, the groove may be formed from the light blocking resin layer side as far as the bonding layer such that the light blocking resin layer has an outside surface that is orthogonal to the first main surface and the second main surface, and the outside surface is in the same flat plane as a side surface of the semiconductor chip.
Further, the groove may formed so as to divide the bonding layer such that the light blocking resin layer has an outside surface that is orthogonal to the first main surface and the second main surface, and the outside surface is parallel to a side surface of the light transmitting chip and to a side surface of the semiconductor chip.
In the another aspect, forming the bonded body may include:
preparing the light transmitting substrate, forming the bonding layer on at least one of the light transmitting substrate and the first main surface of the semiconductor wafer so as to surround the photoreceptor portions on the semiconductor wafer, and adhering the light transmitting substrate and the semiconductor wafer with the bonding layer;
grinding away the semiconductor wafer, from the opposite side to that of the first main surface of the semiconductor wafer to which the light transmitting substrate is attached, so as to form the second main surface;
forming the penetrating electrodes so as to penetrate through the semiconductor wafer from the second main surface to the first wires of the first main surface.
The semiconductor device fabrication method of the present invention may further include forming second wires on the second main surface of the semiconductor wafer so as to be connected to the penetrating electrodes.
The semiconductor device fabrication method of the present invention may further include forming a metal pad at a portion at the end of the penetrating electrodes on the first main surface side.
In the semiconductor device structure of the present invention, the light blocking resin layer is stuck only to the side surfaces of the light transmitting chip and the bonding layer, therefore enabling a semiconductor device to be formed with a thin overall structure, while maintaining reliability, such as in water resistance. The present invention enables a more compact semiconductor device in comparison to the thick semiconductor device in the technology of JP-A No. 2004-363380 above that has resin also formed to the back surface of the semiconductor chip and forms the external terminals after forming posts and raising the electrodes. The structure of the present invention is also equipped with penetrating electrodes and so the mounting surface area becomes more narrow, enabling a more compact semiconductor device, in comparison to the technology of JP-A No. 2007-142058 in which a light blocking film is formed to the side surfaces of an optical member.
In addition, in the fabrication method of the present invention, grooves are formed in the dicing regions, and the light blocking resin is only injected therein, enabling formation while suppressing the cost. According to the present invention, there is a dramatic reduction in processing in comparison to the technology of JP-A No. 2004-363380 above in which a resin layer is formed to the entire semiconductor chip after grooves are formed in the dicing regions, and post forming processing is added for leading out electrodes from the resin layer.
In the fabrication method of the semiconductor device according to the present invention, the groove may be formed from the light blocking resin layer side as far as the bonding layer such that the light blocking resin layer has an outside surface that is orthogonal to the first main surface and the second main surface, and the outside surface is in the same flat plane as a side surface of the semiconductor chip. Namely, according to the present invention, since the light blocking resin layer is configured only covering the side surfaces of the light transmitting chip and not covering the side surfaces of the semiconductor chip, a compact device is enabled in which it is possible to make the size of the device mounting surface area the same as the size of the semiconductor chip. In addition, according to the present invention, only the light transmitting substrate portion is cut, without cutting the semiconductor wafer, in groove forming, and so it is possible to select a blade appropriate for the light transmitting substrate. With regard to this point, in the technology of JP-A No. 2004-363380 above, cutting must be made in the groove forming process with a blade appropriate for both a glass plate and a semiconductor wafer, limiting options for blade selection, however in the present invention there is no such limitation. Also, in comparison to when a blade appropriate to a glass plate is used, in the technology of JP-A No. 2004-363380 where a blade appropriate for both materials is used there is concern of breakage and defects etc. occurring in the cut face of the glass plate and also of affecting the top surface of the glass plate onto which light is incident.
In addition, according to the present invention, since only the light transmitting substrate portion is cut, without cutting the semiconductor wafer, in groove forming, in comparison to the technology of JP-A No. 2004-363380 above, the effective number of semiconductor devices obtained from a single semiconductor wafer can be increased, and yield is improved.
In the semiconductor device fabrication method of the present invention, the groove may be formed so as to divide the bonding layer such that the light blocking resin layer has an outside surface that is orthogonal to the first main surface and the second main surface, and the outside surface is parallel to a side surface of the light transmitting chip and to a side surface of the semiconductor chip. Namely, in the structure of this exemplary embodiment, since the light blocking resin layer is stuck only to the side surfaces of the light transmitting chip and to the bonding layer between the light transmitting substrate and the semiconductor wafer, it is possible to save on material for the light blocking resin layer while maintaining reliability, such as in water resistance etc.
In the semiconductor device fabrication method according to the present invention, forming the bonded body may include: forming the bonding layer on at least one of the light transmitting substrate and/or the first main surface of the semiconductor wafer so as to surround the photoreceptor portions on the semiconductor wafer, and sticking together the light transmitting substrate and the semiconductor wafer with the bonding layer; grinding away the semiconductor wafer, from the opposite side to that of the first main surface of the semiconductor wafer to which the light transmitting substrate is attached, so as to form the second main surface; forming the penetrating electrodes so as to penetrate through the semiconductor wafer from the second main surface to the first wires of the first main surface.
Since the process for forming the bonded body of the light transmitting substrate and the semiconductor wafer, includes a process of grinding away the semiconductor wafer and reducing the thickness of the semiconductor wafer, the light transmitting substrate supports and maintains the strength of the semiconductor wafer, and contributes to avoiding damage to the semiconductor wafer during the processing the bonded body and during transportation thereof.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
Explanation will now be given regarding details of a sensor module of a semiconductor device of an exemplary embodiment of the present invention, with reference to the attached drawings. It should be noted that in each of the drawings, where the same configuration element is shown in separate drawings the same reference number is allocated thereto, and detailed explanation thereof is omitted.
A light blocking resin layer 5 is formed on the bonding layer 9, stuck onto the side surfaces of the glass plate 4.
A photoreceptor portion 11 including photoreceptor elements, such as CMOS sensors etc., is formed to a first main surface of the semiconductor chip 10 to which the bonding layer 9 is attached. On the photoreceptor portion 11, on-chip microlenses may be provided respectively mounted to photoelectric conversion elements. First wires 15 and metal pads 8 are formed, as a sensor circuit, on the first main surface around the periphery of the photoreceptor portion 11 of the semiconductor chip 10, the first wires 15 connected to the photoreceptor portion 11 and to the metal pads 8.
Second wires 15 and external terminals 7 are formed at specific positions on a second main surface (back surface) at the opposite of the semiconductor chip 10 to the side of the first main surface, with an insulating film 14 formed to portions thereof other than at the external terminals 7. The side surfaces of the semiconductor chip 10, which intersect with the first and the second main surfaces and define insulating portions, are exposed in the drawings, but an insulating coating treatment or the like may be performed thereto as required.
Penetrating electrodes 6 are provided in the semiconductor chip 10, below the metal pads 8 that are provided in the vicinity of the external periphery of the first main surface, and the penetrating electrodes 6 electrically connect the wires 15 of the first main surface to the wires 15 of the second main surface. By provision of the penetrating electrodes 6 penetrating through between the first and the second main surfaces, electrical connection to the photoreceptor portion 11 becomes possible through the second wires 15 on the back surface, instead of leading an electrical conductor around the side surfaces of the semiconductor chip. It should be noted that the penetrating electrodes 6 are electrically insulated from the material of the semiconductor chip 10 by an insulating film 16 that pre-covers the entire back surface of the chip and the inside surfaces of the through holes.
A space is provided between the glass plate 4 and the photoreceptor portion 11. However, this space may be filled with a resin of a light transmitting bonding material etc., as long as the glass plate 4 is bonded to the first main surface of the semiconductor chip 10 via the bonding layer 9 at least at the periphery of the photoreceptor portion 11.
The light blocking resin layer 5 that is stuck to the side surfaces of the glass plate 4 has a side surface that is stuck to the bonding layer 9 and that is in the same plane as the side surfaces of the semiconductor chip 10. Therefore, when the glass plate 4 is viewed from the front, the glass plate 4 configures a smaller surface area than that of the semiconductor chip 10. External light passes through the glass plate 4 from the front surface to the back surface, arrives at the main surface of the semiconductor chip 10, and is converted into an electrical signal by the photoreceptor portion 11. Incident light from the side surfaces of the glass plate 4 is blocked by the light blocking resin layer 5. Since there is a black colored light blocking resin layer 5 provided to the side surfaces, a sensor module capable of avoiding light entering from the side surfaces is obtained.
In this manner, since the light blocking resin layer 5 is formed to the side surfaces of the glass plate 4, the glass plate 4 becomes smaller, and incident light from the side surfaces, which produces noise, can be suppressed. In addition, local defects of the glass plate 4 during fabrication processes can be prevented, and by relieving stress at the bonding layer interface an improvement in the reliability can be achieved.
Explanation will now be given of an outline of the process flow in a fabrication method of the sensor module in the first exemplary embodiment, with reference to the substrate cross-sections etc. of the drawings.
Semiconductor Wafer Processing
In the semiconductor wafer state, plural sensor circuit regions are formed in a matrix shape on the front face of the semiconductor wafer by a semiconductor process.
First, each of the sensor circuit regions is formed on a first main surface of a semiconductor wafer 101, as shown in
Next, the first wires 15 are formed, connecting the photoreceptor portion 11 including the photoreceptor elements and the metal pads 8 around the periphery of the photoreceptor portion 11, then plural sensor circuit regions are formed in a matrix array on the first main surface, with lattice shaped spaces left therebetween for use as dicing regions.
Glass Plate Processing
A 300 to 500 μm thickness glass plate for protection of the same size as the semiconductor wafer described above is prepared.
As shown in
The bonding layer 9 may, instead of being formed on the back surface of the glass plate 4, be formed by screen printing directly onto the first main surface of the wafer 101 in positions surrounding each of the sensor circuit regions.
Attachment Process
The glass plate 4 on which the bonding layer 9 has been formed is attached to the wafer 101 that has been formed with the sensor circuit regions.
The glass plate 4 and the wafer 101 are positionally aligned, as shown in
Grinding Process
The back surface of the wafer 101, which is integrated to the glass plate 4, is ground away, as shown in
It should be noted that when the wafer 101 is of the specific thickness already, then the grinding process can be omitted.
Electrode Forming Process
Penetrating electrodes are formed, the second wires and external terminal are formed to the second main surface of the wafer 101 that has been integrated to the glass plate 4.
Through holes 61 (diameter=100 to 200 μm) are formed, as shown in
After this, as shown in
Then, a specific pattern mask (not shown in the drawings), having openings at the through holes where the metal pads 8 are exposed, at portions around these openings where the penetrating electrodes are to be formed, and at portions where the second wires 15 for connecting to the penetrating electrodes are to be formed, is formed in advance on the insulating film 16 at the second main surface of the wafer 101, and the second wires 15 and the penetrating electrodes 6 are formed, as shown in
Then, as shown in
Materials that may be used for the insulating film 14, other than Si02, include SiN, and PI (polyimide); materials that may be used for the wires include one or more conductive material selected from Cu, Al, Ag, Ni, Au etc.; and materials that may be used for the external terminals 7 include SnAg and NiAu.
Light Blocking Resin Layer Forming Process
As shown in
Next, as shown in
Dicing Process
As shown in
The glass plate 4 and the wafer 101 are full cut to a specific size in the above manner, and a sensor module is obtained like the one shown in
According to the above exemplary embodiment, as well as an improvement being expected in the properties of the sensor module for suppressing incident light from the side surfaces of the glass plate 4 with the light blocking resin layer 5, since a wide width of the light blocking resin layer and a narrow the scribe line width of the semiconductor chip can be designed, a large effective number of chips can be obtained on a wafer, so an increase in yield and reduction in cost can also be expected. In addition, since the wide width light blocking resin layer is aligned with the scribe line width of the semiconductor chip 10 and cut finely, forming the light blocking resin layer at the same time as forming each of the sensor modules, the number of processes can be reduced. Also, since there is the resin layer formed to the side surfaces of the brittle glass, defects and breakage of the glass can also be prevented, and handling becomes easy. Furthermore, by providing the black colored light blocking resin layer 5 on the side surfaces of the glass plate 4 the provision of a separate guide cover for light blocking becomes unnecessary, and a cost reduction effect is obtained.
The above fabrication method is applicable to various sensor modules other than a CMOS sensor circuit, including: an image sensor circuit such as a CCD sensor circuit; an illumination intensity sensor circuit; a UV sensor circuit, an IR sensor circuit, or a temperature sensor circuit.
As a second exemplary embodiment a sensor module 1 is configured, as shown in
Processes prior to the light blocking resin layer forming process in the fabrication method of the sensor module are similar to those for producing the bonded body, of the glass plate 4 and the wafer 101, shown in
In the light blocking resin layer forming process, as shown in
As shown in
Next, as shown in
Dicing Process
As shown in
In the above manner, the glass plate 4 and the wafer 101 are full cut to a specific size, and a sensor module is obtained like the one shown in
According to the second exemplary embodiment, light blocking ability is further raised by providing the light blocking resin layer 5 over the entirety of the side surfaces of the sensor module (the glass plate 4, the bonding layer 9 and the semiconductor chip 10), and water resistance of the interface and gas sealing properties thereof can also be raised.
A modification of the first exemplary embodiment is configured, as shown in
In this sensor module 1 of the exemplary modification the side surfaces of the glass plate 4 can be formed in a stepped profile by using plural dicing blades of differing thicknesses in dicing process.
Another exemplary modification of the first exemplary embodiment is configured, as shown in
In the sensor module of this exemplary modification, the side surfaces of the glass plate 4 can be formed into the sloped collimator lens by using in the dicing process a dicing blade in which the thickness of the dicing blade gradually thins on progression in the radial direction toward the outer peripheral end face thereof.
According to this exemplary modification the surface area of the light blocking resin layer 5 is increased, the choice of resin for use as the material of the holder of the lens unit and the material for the bonding member is increased, and the degrees of freedom for design of the camera module are increased.
Furthermore, when slope shaped side surfaces of the glass plate 4 of the exemplary modification are applied, the stray light (arrows in
Number | Date | Country | Kind |
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2008-200010 | Aug 2008 | JP | national |