WO2016207979A1

WO2016207979A1 - Semiconductor device, and semiconductor device manufacturing method

Info

Publication number: WO2016207979A1
Application number: PCT/JP2015/068070
Authority: WO
Inventors: 智史乾
Original assignee: オリンパス株式会社
Priority date: 2015-06-23
Filing date: 2015-06-23
Publication date: 2016-12-29
Also published as: JPWO2016207979A1

Abstract

Provided are: a semiconductor device wherein reliability of a connecting section can be improved, while reducing dimensions; and a method for manufacturing the semiconductor device. An image pickup unit 100 of the present invention is characterized by being provided with: an image pickup element 10, which has a light receiving section 11 formed at a main surface center section, and a plurality of electrode pads 12 formed around the light receiving section 11; a flexible printed board 30 having a plurality of inner leads 32 respectively connected to the electrode pads 12 via bumps 13; and an optical member 20, which seals the light receiving section 11 of the image pickup element 10, and which has an alignment section for the inner leads 32, said alignment section having at least one groove section 21 that is formed in a side surface for the purpose of housing a connecting section that connects the electrode pads 12 and the inner leads 32 to each other.

Description

Semiconductor device and method of manufacturing semiconductor device

The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device.

Conventionally, an endoscope is widely used for various examinations in the medical field and the industrial field. Among these, medical endoscopes do not cut the subject by inserting a flexible insertion portion having a solid-state imaging device at the tip and having an elongated shape into the subject such as a patient. In any case, it is widely used because it can acquire an in-vivo image in a body cavity and can perform a treatment treatment by projecting a treatment tool from the tip of the insertion portion as needed.

In general, the imaging device used in such an endoscope covers the light receiving surface of the CCD chip with a cover glass and connects the inner lead of the TAB tape to the electrode provided on the outer peripheral edge portion of the light receiving surface. A chip is connected to an electronic component or an external information processing device (see, for example, Patent Document 1).

In recent years, in order to reduce the burden on the subject, it is required to reduce the diameter of the insertion tip of the endoscope, and the miniaturization of the CCD chip is also being studied. When the size of the CCD chip is reduced, the distance between the electrodes provided at the outer peripheral edge is also narrowed, so there is a high possibility that a short circuit or the like may occur due to the positional deviation between the electrodes and the inner leads.

On the other hand, a dummy electrode is disposed between a plurality of electrodes used for transmitting a signal or the like as a technique for reducing the positional deviation between the electrode and the inner lead to prevent the occurrence of a short circuit or the like. A technique has been proposed for preventing misalignment by connecting dummy wires (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 11-76152 Unexamined-Japanese-Patent No. 2013-239654

However, the technique described in Patent Document 2 requires an installation space for the use of the dummy wiring and / or the dummy electrode, which hinders the miniaturization of the semiconductor element and the semiconductor device using the same. Have.

The present invention has been made in view of the above, and an object of the present invention is to provide a semiconductor device capable of improving the reliability of a connection portion while achieving downsizing, and a method of manufacturing the semiconductor device.

In order to solve the problems described above and achieve the object, a semiconductor device according to the present invention includes an element portion formed in the central portion of the main surface and a plurality of electrode pads formed around the element portion. A flexible printed circuit board having a semiconductor chip having a plurality of inner leads connected respectively to the plurality of electrode pads via bumps, and an element portion of the semiconductor chip and sealing the electrode pads and the inner side And an optical member having a positioning portion of the inner lead in which at least one groove portion for receiving a connection portion with the lead is formed.

The semiconductor device according to the present invention is characterized in that, in the above-mentioned invention, the groove portions are formed at the same intervals as the pitch intervals of the electrode pads and in the same number as the number of the electrode pads.

The semiconductor device according to the present invention is characterized in that in the above-mentioned invention, the height of the positioning portion is the sum of the thickness of the inner lead after connection and the height of the bump.

In the semiconductor device according to the present invention as set forth in the invention described above, the positioning portion is characterized in that a gap is formed on the side of the connection surface with the semiconductor chip.

A method of manufacturing a semiconductor device according to the present invention is the method of manufacturing a semiconductor device according to any one of the above, wherein a bonding step of bonding a semiconductor chip and an optical member, a side surface of the optical member Including an alignment step of inserting an inner lead into the formed groove and aligning the electrode pad and the inner lead, and a connection step of connecting the electrode pad and the inner lead via a bump. It features.

In the method of manufacturing a semiconductor device according to the present invention, in the above-mentioned invention, a film forming step of forming a metal film and a photoresist on a thin film to be a material of the optical member, and the groove portion in the metal film A patterning step of patterning the shape of the groove, a groove forming step of etching the optical member using the patterned metal film as a mask to form the groove, and a singulation step of removing the metal film and singulating And D. an optical member manufacturing process.

According to the present invention, since the electrode pad and the inner lead can be accurately positioned without using a dummy wiring and / or a dummy electrode, it is possible to provide a semiconductor device excellent in the reliability of the connection while achieving miniaturization. be able to.

FIG. 1 is a view schematically showing an entire configuration of an endoscope system according to a first embodiment of the present invention. FIG. 2 is a side view of the imaging unit used in the endoscope of FIG. FIG. 3 is a front view of the imaging unit shown in FIG. FIG. 4 is a partially enlarged side view of the connection portion of the imaging unit of FIG. FIG. 5 is a cross-sectional view of the imaging unit of FIG. 3 taken along line AA. FIG. 6 is a diagram for explaining a method of manufacturing an optical member. FIG. 7 is a partially enlarged view of the surface of the glass wafer after metal film etching. FIG. 8 is a front view of an imaging unit according to a modification of the first embodiment. FIG. 9 is a partially enlarged side view of the imaging unit according to the second embodiment. FIG. 10 is a cross-sectional view of the imaging unit of FIG. FIG. 11 is a partially enlarged side view of the imaging unit according to the third embodiment. FIG. 12 is a cross-sectional view of the imaging unit of FIG.

In the following description, an endoscope provided with a semiconductor device that functions as an imaging unit will be described as a mode for carrying out the present invention (hereinafter, referred to as “embodiment”). Further, the present invention is not limited by the embodiment. Furthermore, in the description of the drawings, the same parts are given the same reference numerals. Furthermore, it should be noted that the drawings are schematic, and the relationship between the thickness and width of each member, the ratio of each member, and the like are different from reality. In addition, among the drawings, there are included parts having different dimensions and ratios.

Embodiment 1
FIG. 1 is a view schematically showing an entire configuration of an endoscope system according to a first embodiment of the present invention. As shown in FIG. 1, the endoscope system 1 includes an endoscope 2, a universal cord 5, a connector 6, a light source device 7, a processor (control device) 8, and a display device 9.

The endoscope 2 takes an in-vivo image of the subject by inserting the insertion unit 3 into the subject, and outputs an imaging signal. The cable inside the universal cord 5 is extended to the tip of the insertion portion 3 of the endoscope 2 and connected to an imaging unit provided at the tip 3 b of the insertion portion 3.

The connector 6 is provided at the base end of the universal cord 5, connected to the light source device 7 and the processor 8, and a predetermined signal is output as an imaging signal (output signal) output from the imaging unit of the distal end 3b connected to the universal cord 5. While performing processing, the imaging signal is analog-to-digital converted (A / D conversion) and output as an image signal.

The light source device 7 is configured using, for example, a white LED. The pulsed white light that the light source device 7 lights up becomes illumination light that is emitted toward the subject from the tip of the insertion portion 3 of the endoscope 2 via the connector 6 and the universal cord 5.

The processor 8 performs predetermined image processing on the image signal output from the connector 6 and controls the entire endoscope system 1. The display device 9 displays the image signal processed by the processor 8.

The proximal end side of the insertion portion 3 of the endoscope 2 is connected to the operation unit 4 provided with various buttons and knobs for operating the endoscope function. The operation unit 4 is provided with a treatment tool insertion port 4a for inserting treatment tools such as a forceps, an electric knife, and a test probe into a body cavity of a subject.

The insertion portion 3 includes a distal end portion 3b provided with an imaging unit, a vertically bendable curved portion 3a continuously provided on the base end side of the distal end portion 3b, and a proximal end side of the curved portion 3a. And a flexible tube portion 3c. The bending portion 3a is bent in the vertical direction by the operation of a bending operation knob provided on the operation portion 4, and can be bendable in, for example, upper and lower two directions along with the pulling and relaxing of the bending wire inserted into the insertion portion 3. It has become.

The endoscope 2 is provided with a light guide for transmitting the illumination light from the light source device 7, and an illumination window is disposed at the emission end of the illumination light by the light guide. The illumination window is provided at the distal end 3b of the insertion portion 3, and the illumination light is emitted toward the subject.

Next, an imaging unit provided at the distal end 3b of the endoscope 2 will be described. FIG. 2 is a side view of the imaging unit used in the endoscope of FIG. FIG. 3 is a front view of the imaging unit shown in FIG. FIG. 4 is a partially enlarged side view of the connection portion of the imaging unit of FIG. FIG. 5 is a cross-sectional view of the imaging unit of FIG. 3 taken along line AA.

The imaging unit 100 includes an imaging element 10 having a light receiving unit 11 formed in the central portion of the main surface, an optical member 20 for sealing the light receiving unit 11, and a flexible printed circuit 30. In the present specification, the optical member side of the imaging unit 100 is referred to as the front side, and the side on which a signal cable described later is disposed is referred to as the proximal side.

The imaging element 10 includes five electrode pads 12 around the light receiving unit 11 which is an element unit formed in the central portion of the main surface. Bumps 13 made of gold (Au), solder or the like are formed on the electrode pads 12.

The optical member 20 is made of a material such as glass or a resin having an optical characteristic similar to that of glass, and is bonded to the imaging device 10 by an adhesive. Grooves 21 that define the positions of the electrode pads 12 and the inner leads are formed on the side surfaces of the optical member 20. The grooves 21 are formed so as to penetrate from the front surface side to the back surface side of the optical member 20, and are formed in the same number as the number of the electrode pads 12 at the same pitch intervals of the electrode pads 12. The side surface of the optical member 20 on which the groove 21 is formed functions as a positioning portion 23 for the bump 13 and the inner lead 32 on the electrode pad 12.

The flexible printed board 30 (hereinafter referred to as “FPC board”) has an insulating base 31 and a wiring layer (not shown) formed inside the base 31, and the wiring layer is the base 31. To form the inner leads 32. The FPC board 30 extends from the imaging element 10 in the optical axis direction, and a laminated board 40 having a plurality of conductor layers is connected to the surface of the extended FPC board 30. An electronic component 50 constituting a drive circuit of the imaging device 10 is mounted on the laminated substrate 40, and a via (not shown) for electrically connecting a plurality of conductive layers is formed in the laminated substrate 40. . The conductor 61 of the cable 60 is connected to the base end side of the laminated substrate 40. Note that electronic components other than the electronic components that constitute the drive circuit of the imaging device 10 may be mounted on the laminated substrate 40.

Generally, the diameter of the electrode pad 12 of the imaging device 10 used in the endoscope 2 is 30 to 100 μm, the distance between the electrode pads 12 is 20 to 100 μm, and the pitch between the electrode pads 12 is 50 to 200 μm. . The diameter of the bumps 13 disposed on the electrode pads 12 is 25 to 100 μm, and the height of the bumps 13 is 15 to 30 μm. The inner lead 32 connected to the electrode pad 12 through the bump 13 has a width of 25 to 100 μm and a thickness of about 15 to 25 μm in accordance with the diameter of the bump 13. The width r1 of the groove 13 which is the positioning portion 23 of the bump 13 and the inner lead 32 on the electrode pad 12 is preferably formed in accordance with the size of the bump 13 and the inner lead 32, and the diameter of the bump 13 or the inner Preferably, it is about 110 to 120% of the width of the lead 32. The length r2 of the groove 21 is preferably at least 50% or more of the diameter of the bump 13. By setting the length r2 to 80 to 120%, accurate positioning can be performed, and enlargement of the imaging unit 100 is suppressed. it can. The height r3 of the groove 21 is preferably equal to or less than the sum of the thickness of the inner lead 32 after connection and the height of the bump 13.

The imaging unit 100 positions and connects the optical member 20 so that the electrode pad 12 in which the bump 13 is formed in the groove 21 is disposed on the imaging element 10 in which the bump 13 is formed on the electrode pad 12. Then, the inner lead 32 of the FPC board 30 is inserted into the groove portion 21 for positioning, and heat and pressure are applied from above the inner lead 32 with a heat tool to connect the inner lead 32 with the electrode pad 12 by the bump 13. In order to collectively connect the five inner leads 32 with a heat tool, the sum of the thickness of the inner leads 32 before connection and the height of the bumps 13 takes into account the decrease in height of the bumps 13 due to melting at the time of connection It is preferable to make the height of the groove 21 higher than the height r3. However, this is not the case when the inner leads 32 are individually connected. The connection between the inner leads and the bumps may be by an ultrasonic connection method using an ultrasonic tool. In addition, after the imaging unit 100 connects the imaging element 10 and the optical member 20, the bump 13 may be formed on the electrode pad 12 and then connected to the inner lead 32.

The connection portion between the electrode pad 12 and the inner lead 32 may be sealed with a sealing resin. As the sealing resin, it is preferable to use a colored sealing resin which does not transmit light, in order to prevent oblique incidence of light from the groove 21 to the light receiving portion 11. In order to prevent oblique incidence on the light receiving portion 11 from the groove 21 without using a sealing resin, it is preferable to apply a light shielding paint in the groove 21.

The optical member 20 can also be processed and shaped by a dicing blade, a laser or the like, but manufacturing by a semiconductor process is preferable in terms of cost and accuracy. The semiconductor process manufacture of the optical member 20 will be described with reference to the drawings. FIG. 6 is a diagram for explaining a method of manufacturing an optical member. FIG. 6 shows a cross section of the glass wafer 25 which is a material of the optical member 20. However, for the purpose of understanding the invention, a partial cross section of the glass wafer 25 is shown enlarged.

First, a metal film 26 such as gold or aluminum is formed on the surface of the glass wafer 25. The metal film 26 is formed by evaporation, sputtering or the like. Subsequently, a photoresist is applied on the metal film 26 to form a resist layer 27 (see FIG. 6A).

The resist layer 27 is exposed and developed through a mask, and after patterning the shape of the groove portion 21 of the optical member 20 in the resist layer 27, the metal film 26 is etched (see FIG. 6B). After the metal film 26 is etched, the resist layer 27 is removed (see FIG. 6C). FIG. 7 is a partially enlarged view of the surface of the glass wafer 25 after the etching of the metal film 26 (after removing the resist layer 27). In FIG. 7, dotted lines show the final shape of the optical member 20. As shown in FIG. 7, the portion corresponding to the groove 21 of the metal film 26 is removed by etching.

The glass wafer 25 is etched using the metal film 26 in which the shape of the groove 21 is patterned by etching as a mask (see FIG. 6D). The groove 21 is formed in the glass wafer 25 by this etching. By forming the groove 21 by photolithography, an optical member can be manufactured with high accuracy.

After removing the metal film 26 from the glass wafer 25 in which the groove 21 is formed (see FIG. 6E), the glass wafer 25 is singulated by dicing to obtain the optical member 20 (see FIG. 6F). When forming the groove 21 by etching the glass wafer 25, the resist layer 27 may be directly formed on the surface of the glass wafer 25 without forming the metal film 26, and the groove 21 may be formed by photolithography. In consideration of the thickness of the wafer 25, it is preferable to form the metal film 26 as a mask. The metal film 26 and the glass wafer 25 may be etched by either wet etching or dry etching.

After the optical member 20 is manufactured by the above-described process, the imaging unit 100 can be manufactured by bonding to the imaging device 10, but the glass wafer 25 is bonded to the silicon wafer of the imaging device 10 in the wafer state before being separated. After bonding, the groove 21 may be formed in the glass wafer 25 according to the above process, and the silicon wafer and the glass wafer 25 may be simultaneously separated.

The imaging unit 100 according to the first embodiment can be easily positioned with the electrode pad 12 by inserting the inner lead 32 of the FPC board 30 into the groove 21 of the optical member 20. Further, since the inner lead 32 is positioned by the groove portion 21, the possibility of a short circuit due to the positional deviation of the inner lead 32 can be reduced. Furthermore, since the groove 21 functions as a dam, when the inner lead 32 and the electrode pad 12 are connected, the occurrence of a short circuit or the like due to the outflow of the bump 13 can be prevented. Furthermore, since the dummy electrode and the dummy wiring are not used, the imaging unit 100 can be miniaturized.

In the first embodiment described above, the imaging unit has been described as an example of the semiconductor device, but the semiconductor device of the present invention is not limited to the imaging unit, and is also applicable to semiconductor devices using optical members such as MEMS devices. It is possible.

In the first embodiment described above, the grooves 21 equal in number to the electrode pads 12 are formed in the positioning portion 23 of the optical member 20, and the inner leads 32 are inserted into the grooves 21 for positioning. The groove may be single as long as the electrode pad can be positioned. FIG. 8 is a front view of an imaging unit according to a modification of the first embodiment.

In the imaging unit 100A according to the modification of the first embodiment, one groove 21A is formed in the positioning portion 23A. The width r1 'of the groove 21A is large enough to accommodate all the bumps 13 and the inner leads 32. The width of the inner lead 32 is about the same as the diameter of the bump 13, and the width r1 'of the groove 21A is adjusted to the length r4 of the outermost side of the diameter of the bump 13 or the width of the inner lead 32, whichever is larger. By forming it, alignment can be easily performed.

When only one groove is formed, the size is made to accommodate all the bumps 13 and the inner leads 32 as in this modification, and each bump 13 and the inner leads 32 at the end or the center It may be a groove having a size to accommodate each one of the bumps 13 and the inner lead 32 of the portion.

Second Embodiment
In the imaging unit according to the second embodiment, the positioning portion of the optical member is provided with a recess on the side of the connection surface with the imaging device. FIG. 9 is a partially enlarged side view of the imaging unit according to the second embodiment. FIG. 10 is a cross-sectional view of the imaging unit of FIG. The cross-sectional view of FIG. 10 is a cross section at the same position as the cross section AA of the imaging unit 100 of FIG.

In the imaging unit 100B according to the second embodiment, the positioning portion 23B of the optical member 20B is provided with a recess 22 on the connection surface side with the imaging device 10, and a gap is formed between the recess 22 and the imaging device 10. Although the imaging device 10 and the optical member 20B are bonded by an adhesive, leakage of the adhesive may occur in the groove 21B depending on the amount of adhesive used and the heating and pressing conditions at the time of bonding. . Before the bumps 13 are formed on the electrode pads 12, the imaging device 10 and the optical member 20B are joined by an adhesive, and the concave portion 22 is formed in the optical member 20B even when the adhesive leaks to the positioning portion 23B side. As a result, the adhesive does not flow into the recess 22 and does not flow onto the electrode pad 12, and the connection reliability can be improved. The height r5 of the recess 22 is preferably suitably changed according to the thickness of the adhesive used for bonding the imaging device 10 and the optical member 20B, but is at least 1 μm or more and 50% of the height r3 of the groove 21B. It is preferably less than 30%, preferably less than 30%.

Third Embodiment
In the imaging unit according to the third embodiment, the height of the positioning portion of the optical member is formed lower than the height of the optical member on the light receiving portion. FIG. 11 is a partially enlarged side view of the imaging unit according to the third embodiment. FIG. 12 is a cross-sectional view of the imaging unit of FIG. The cross-sectional view of FIG. 12 is a cross-section at the same position as the AA cross section of the imaging unit 100 of FIG.

In the imaging unit 100C according to the third embodiment, the height r3 of the positioning portion 23C of the optical member 20C is smaller than the height r6 of the optical member 20C on the light receiving portion 11 of the imaging device 10. The height r3 of the positioning portion 23C is determined according to the height of the bump 13 used and the thickness of the inner lead 32, but the height r6 of the optical member 20C on the light receiving portion 11 is necessary according to the optical characteristics The height should be determined in accordance with the material used for the optical member 20C. In the third embodiment, the height r6 of the optical member 20C on the light receiving portion 11 is higher than the height r3 of the positioning portion 23C, but if necessary, the height r6 of the optical member 20C on the light receiving portion 11 is It may be lower than the height r3 of the positioning portion 23C.

DESCRIPTION OF SYMBOLS 1 endoscope system 2 endoscope 3 insertion part 3a curved part 3b tip part 3c flexible tube part 4 operation part 4a treatment tool insertion port 5 universal cord 6 connector 7 light source device 8 processor 9 display device 10 imaging element 11 light receiving part 12 electrode pad 13

bump

20, 20A, 20B, 20C

optical member

21, 21A, 21B groove 22

concave portion

23, 23A, 23B, 23C positioning portion 25 glass wafer 26 metal film 27 resist layer 30 flexible printed board 31 base 32 inner lead 40 laminated substrate 50 electronic component 60 cable 61

conductor

100, 100A, 100B, 100C imaging unit

Claims

A semiconductor chip having an element portion formed in the central portion of the main surface and a plurality of electrode pads formed around the element portion;
A flexible printed circuit board having a plurality of inner leads respectively connected to the plurality of electrode pads via bumps;
An optical member having a positioning portion of the inner lead, in which the element portion of the semiconductor chip is sealed, and at least one groove portion for housing the connection portion between the electrode pad and the inner lead is formed on the side surface.
A semiconductor device comprising:
2. The semiconductor device according to claim 1, wherein the groove portions are formed at the same intervals as the pitch intervals of the electrode pads and the same number as the number of the electrode pads.
The semiconductor device according to claim 1, wherein a height of the positioning portion is a sum of a thickness of the inner lead after connection and a height of the bump.
The semiconductor device according to any one of claims 1 to 3, wherein the positioning portion has a gap formed on the side of the connection surface with the semiconductor chip.
A method of manufacturing a semiconductor device according to any one of claims 1 to 4, wherein
A bonding step of bonding the semiconductor chip and the optical member;
Aligning the electrode pad and the inner lead by inserting an inner lead into a groove formed on the side surface of the optical member;
A connection step of connecting the electrode pad and the inner lead via a bump;
A method of manufacturing a semiconductor device, comprising:
Forming a metal film and a photoresist on a thin film to be a material of the optical member;
A patterning step of patterning the shape of the groove in the metal film by photolithography;
A groove forming step of etching the optical member using the patterned metal film as a mask to form the groove;
6. The method of manufacturing a semiconductor device according to claim 5, further comprising: an optical member manufacturing step including the step of separating the metal film and separating the metal film.