JP2014207371A - Imaging apparatus, manufacturing method of imaging apparatus, and junction strength test method of imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus 1A which facilitates a strength test of a junction.SOLUTION: The imaging apparatus 1A comprises: a wiring board 20 including a plurality of flying leads 23 respectively extending from a plurality of inner leads 21 disposed in a base film 22; and an imaging chip 10 in which a plurality of junction terminals 12 joined with distal end portions of the flying leads 23 are provided in a columnar shape on a streight line parallel with a terminal side. A junction of a flying lead 23D protruding from a notch 24 formed on the terminal side of the base film 22 and longer than the other flying leads and a junction terminal 12D is fractured.

Description

  The present invention relates to an imaging device in which an imaging chip is bonded to a flying lead of a wiring board, a method for manufacturing the imaging device, and a bonding strength test method for the imaging device.

  Japanese Patent Application Laid-Open No. 2009-231400 discloses joining bumps of a semiconductor chip and flying leads of a wiring board in order to transmit and receive signals to and from the semiconductor chip. In order to ensure the reliability of the joint, it is necessary to actually measure the joint strength. In order to perform the bonding strength test, it is necessary to hook the hook of the tensile test jig on the flying lead.

  However, in order to reduce the size of the device, it is preferable that the distance between the end face of the semiconductor chip and the end face of the wiring board after bonding, that is, the length of the flying lead between the semiconductor chip and the wiring board is shorter. In particular, there is a strong demand for downsizing of an imaging apparatus for an electronic endoscope.

  For this reason, in a small imaging device, it is not easy to hook the hook of the tensile test jig on the flying lead, and the bonding strength test may not be easy.

  Further, since the bonding strength test is a destructive test, the device after the test cannot be used as a product, and in particular, in the case of small-quantity, multi-product production, it has been a cause of a decrease in manufacturing yield.

JP 2009-231400 A

  An object of the present invention is to provide a small-sized imaging device that can easily perform a bonding strength test of a bonding portion, a method for manufacturing the imaging device, and a bonding strength testing method for an imaging device that can be easily performed.

  An image pickup apparatus according to an embodiment of the present invention includes a wiring board having a plurality of flying leads respectively extended from a plurality of inner leads disposed on a base film, and a plurality of joints connected to the front ends of the flying leads. An image pickup device, wherein the joining terminals are arranged on a straight line parallel to the end side, and projecting from a notch formed on the end side of the base film, The joining between the flying lead longer than the flying lead and the joining terminal is broken.

  Further, in the imaging device of another embodiment, the tips of a plurality of flying leads including a flying lead that is extended from an inner lead disposed on a base film and is longer than the other flying leads are orthogonal to the extending direction. A wiring board on a straight line, and an imaging chip in which joining terminals each joined to the tip of the flying lead of the wiring board are arranged on a straight line parallel to the end side.

  In another embodiment, the manufacturing method of the imaging device includes a step of manufacturing an imaging chip in which a plurality of joint terminals are arranged on a straight line parallel to the end side, and an inner lead is arranged on the base film. Cutting the circuit board, when the end of the base film of the wiring board is selectively removed and the leading end of the inner lead becomes a flying lie protruding from the end of the base film. The step of forming a flying lead longer than other flying leads by forming the notch, and the step of joining the joining terminal of the imaging chip and the tip of the flying lead of the wiring board, Are provided.

  Furthermore, the bonding strength test method for an imaging apparatus according to another embodiment includes a step of manufacturing an imaging chip in which a plurality of bonding terminals are arranged on a straight line parallel to an edge, and an inner lead is arranged on a base film. A step in which the provided wiring board is manufactured, and when the end portion of the base film of the wiring board is selectively removed, and the leading end portion of the inner lead becomes a flying Lee protruding from the end side of the base film. By forming the notch, the step of forming the flying lead that is longer than the other flying leads, the joining terminal of the imaging chip, and the tip of the flying lead of the wiring board are joined. A process, a process in which a hook of a tensile test jig is hooked on the flying lead that is longer than other flying leads, and a stress while pulling up the tensile test jig It is to be measured, comprising the steps of: strength of the bonding portion is measured, the.

  ADVANTAGE OF THE INVENTION According to this invention, the small imaging device with which the joining strength test of a junction part is easy, the manufacturing method of the said imaging device, and the joining strength test method of the imaging device which can be performed easily can be provided.

It is a top view of the imaging device of a 1st embodiment. It is sectional drawing along the II-II line of FIG. 1 of the imaging device of 1st Embodiment. It is a flowchart for demonstrating the manufacturing method of the imaging device of 1st Embodiment, and the joint strength test method of an imaging device. It is a top view for demonstrating the manufacturing method of the imaging device of 1st Embodiment. It is a top view for demonstrating the manufacturing method of the imaging device of 1st Embodiment. It is a side view for demonstrating the manufacturing method of the imaging device of 1st Embodiment. It is a side view for demonstrating the joining strength test method of the imaging device of 1st Embodiment. It is a side view for demonstrating the joining strength test method of the imaging device of 1st Embodiment. It is a top view of the imaging device of a 2nd embodiment. It is a top view of the imaging device of a 2nd embodiment. It is sectional drawing along the XI-XI line of FIG. 10 of the imaging device of 2nd Embodiment.

<First Embodiment>
As shown in FIGS. 1 and 2, the imaging device 1 of the present embodiment includes an imaging chip 10 and a wiring board 20 that are rectangular in plan view. A light receiving portion 11 made of a CMOS image sensor or the like is formed on the main surface of the imaging chip 10 made of a semiconductor such as silicon, and a plurality of junction terminals 12 connected to the light receiving portion 11 by respective wirings 13. Is arranged. The plurality of junction terminals 12 are arranged in a line on a straight line L2 parallel to the end side.

  In the wiring board 20, for example, an inner lead 21 made of a conductor such as copper is disposed on a base film 22 made of an insulating resin such as polyimide. A chip component 25 is mounted on the land electrode 21 </ b> A of the inner lead 21. The inner lead 21 is covered with a protective layer 26 made of an insulating resin.

  A flying lead 23 having a length D is extended from the end of the inner lead 21. As will be described later, by removing the base film 22 without removing the inner lead 21 at the end of the wiring board, the leading end of the inner lead 21 becomes a flying lead 23. That is, the inner lead 21 and the flying lead 23 are inseparable and made of the same material.

  As the length between the end faces (distance between end faces) G between the end face of the image pickup chip 10 and the end face of the base film 22 is shorter, the image pickup apparatus can be more easily downsized. Here, a notch 24 is formed in the outermost peripheral portion of the end surface of the base film 22 of the wiring board 20. For this reason, the length D2 of the flying lead 23D protruding from the notch 24 is longer than the length D1 of the other flying leads 23. Since the flying lead 23D has a long length D2, the length (G2) between the end face of the imaging chip 10 and the end face of the base film 22 is longer than the end face length G1 of the other flying leads 23. For this reason, it is easy to hook the hook 30 (see FIG. 7) of the tensile test jig on the flying lead 23D.

  For this reason, the imaging device 1 has a short end-to-end length G1 and is small, but the flying lead 23D for the bonding strength test has a long end-to-end length G2 so that the joining strength test is easy.

  Next, the manufacturing method of the imaging device 1 and the bonding strength test method will be described along the flowchart of FIG.

<Step S11>
A plurality of substantially rectangular light receiving portions 11 made of CMOS image sensors are formed on the main surface of a semiconductor wafer made of silicon or the like using a known semiconductor manufacturing technique. The light receiving unit 11 may be a CCD or the like. And in order to transmit / receive a signal with the light-receiving part 11, the several junction terminal 12 each connected with the light-receiving part 11 with the wiring 13 is arrange | positioned in a line.

  The junction terminal 12 is a gold bump disposed on a flat electrode pad by a stud bump method. The bump forming method may be a plating method, and the material may be solder.

  Then, the plurality of imaging chips 10 are manufactured by cutting the semiconductor wafer into pieces. A cover glass or the like may be bonded so as to cover the light receiving unit 11 of the imaging chip 10.

<Step S12>
As shown in FIG. 4, a wiring board 20 </ b> X in which inner leads 21 are arranged on a base film 22 is manufactured using a known wiring board manufacturing technique. The end face L1 of the base film 22 is orthogonal to the longitudinal direction. A land electrode 21 </ b> A is formed on the inner lead 21. Except for the land electrode 21A, the protective layer 26 is covered. The protective layer 26 and the land electrode 21A may not be formed.

  As the base film 22, polyimide, polyester, liquid crystal polymer (LCP), or the like can be used. The inner lead 21 is a copper wiring, and is arranged by a copper foil etching method or a copper plating method.

<Step S13>
As shown in FIG. 5, by selectively removing the base film 22 at the end of the base film 22 of the wiring board 20 </ b> X, the leading end of the inner lead 21 protrudes from the end of the base film 22. It becomes. The selective removal of the base film 22 is performed by an etching method using a solvent, for example. That is, an organic solvent that dissolves the base film 22 but does not affect the inner leads 21 is used. For example, when the base film 22 is made of polyimide and the inner lead 21 is made of copper, wet etching is performed using a non-hydrazine-based alkaline aqueous solution as a solvent.

  A mask that is not dissolved by an organic solvent is formed on the surface of the base film 22 other than the flying lead 23 forming portion.

  Since the end surface L1 of the base film 22 is orthogonal to the longitudinal direction, the tips of the plurality of inner leads 21 are on a straight line orthogonal to the longitudinal direction.

  At the time of forming the flying lead 23, the base film 22 is removed so as to form a notch 24 at the end of the outer periphery where the inner lead 21D is disposed. For this reason, the length D2 of the outermost flying lead 23D is longer than the other flying leads 23.

  There may be two or more flying leads 23D for bonding strength test protruding from the notch 24.

  As shown in FIG. 5, a capacitor, an inductor, a semiconductor chip, and the like are mounted on the land electrode 21A by, for example, solder bonding.

  In the description of the embodiment, the single-sided wiring board in which the inner leads 21 are disposed only on one side is shown as the wiring board 20, but a double-sided wiring board or a multilayer wiring board may be used.

  Note that the order of the imaging chip manufacturing process in step S11 and the wiring board manufacturing process in steps S12 and S13 may be reversed.

  In addition, the imaging chip may be provided with a junction terminal group including a plurality of junction terminals 12 along two or more end faces. In this case, in the next joining step, each wiring board is joined to each joining terminal group. However, as long as the notch 24 is formed on the at least one wiring board like the wiring board 20. Good.

<Step S14>
As shown in FIG. 6, the joining terminal 12 of the imaging chip 10 and the tip of the flying lead 23 of the wiring board 20 are joined. That is, the plurality of flying leads 23 (23D) and the plurality of joining terminals 12 (12D) are aligned and thermocompression bonded by a collective bonding method. It is not easy to align the joining terminals 12 arranged at a narrow pitch with the inner leads 21 of the wiring board 20. However, alignment of the flying lead 23 extended from the inner lead 21 and the joining terminal 12 is easy.

  As a bonding method, a single point bonding method in which the flying lead 23 and the bonding terminal 12 are connected one by one, an ultrasonic combined thermocompression bonding method, or the like may be used.

  At least a part of the flying lead 23D is in the space between the end face of the imaging chip 10 and the end face of the base film 22, and the hook 30 (see FIG. 7) of the tensile test jig is hooked on the flying lead 23D. If possible, a part of the base film 22 may be on the imaging chip 10. In this case, since the imaging chip 10 and the base film 22 can be bonded and fixed, the reliability of the imaging apparatus is improved.

  At this stage, the imaging device 1 can also be regarded as a finished product.

<Step S15>
In the imaging device 1, a joint strength test for ensuring the reliability of the joint is performed as a start-up inspection or a sampling inspection.

  In the bonding strength test, as shown in FIG. 7, the stress is measured while gradually moving the jig in the vertical direction with the hook 30 of the tensile test jig of the tensile tester hooked on the flying lead 23D. Done in

  The hook 30 is J-shaped or L-shaped so that the tip end can be easily hooked on the flying lead 23D, and has a diameter (width) W of 50 μm, for example. For this reason, in order to insert the hook 30, it is preferable that there is a space having a length (G2) of 100 μm or more and a width of 250 μm or more between the end face of the imaging chip 10 and the end face of the base film 22. The length (G2) is preferably 150 μm or more. Even if the length (G2) exceeds 250 μm, the effect does not change. That is, the length (G2) of the flying lead on which the hook 30 can be hooked with respect to the diameter (width) W of the hook 30 is preferably 2 W or more and 5 W or less. On the other hand, the length (G1) between the end faces of the other flying leads is preferably 0 or more and W or less for miniaturization.

  The distance (length: G) between the end face of the imaging chip 10 and the end face of the base film 22 is preferably as short as possible for downsizing the apparatus. In the imaging apparatus 1, since the test is performed using the flying lead 23D in which a space for inserting the hook 30 is formed, the length G1 of the other flying leads 23 can be shortened. For this reason, the imaging device 1 is small.

  The notch 24, that is, the inner lead 21D may be formed at the center of the end side of the base film 22, but is preferably formed at the outermost periphery for improving work efficiency.

  As shown in FIG. 8, when the hook 30 is gradually pulled up, the connection between the flying lead 23D and the connection terminal 12D is eventually broken. The stress at the time of breaking is the bonding strength. In addition, not only does the joint surface break, but when the joint strength is strong, the joint terminal 12 may break from the wiring board 20 or the flying lead may break.

  As described above, the imaging device 1 includes the wiring board 20 having the plurality of flying leads 23 protruding from the base film 22, and the imaging chip 10 having the joint terminals 12 connected to the plurality of flying leads 23 by bonding. And a notch 24 is formed in a portion of the base film 22 where the flying lead 23D protrudes.

  In other words, the imaging device 1 has the leading ends of the plurality of flying leads 23 including the flying leads 23 </ b> D extending from the inner leads 21 disposed on the base film 22 longer than the other flying leads 23. Imaging in which the wiring board 20 on the straight line L1 orthogonal to the installation direction and the joining terminals 12 each joined to the tip of the flying lead 23 of the wiring board 20 are arranged in a line parallel to the end side. Chip 10.

  The imaging device 1 can easily perform a strength test of the joint. That is, by forming the notch 24, which is a bonding pull strength test space, in a part of the base film 22 on which the flying lead 23D is formed, the bonding strength can be easily measured and confirmed, thus ensuring a reliable inspection. Can contribute to the stability and improvement of quality.

  Moreover, according to the manufacturing method of the imaging device of the embodiment, it is possible to manufacture a small imaging device in which a joint strength test of the joint portion is easy. Furthermore, the bonding strength test method for the imaging device of the embodiment can be easily performed.

Second Embodiment
Since the imaging device 1A of the second embodiment is similar to the imaging device 1, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 11, in the imaging apparatus 1A, the flying lead 23D1 that is longer than the other flying leads 23 is a dummy lead for a bonding strength test. In this specification, the dummy lead is the flying lead 23 in which a bonding failure with the bonding terminal 12D1 does not affect the input / output signal of the imaging chip. The tip of the flying lead 23D1 of the wiring board 20 and the joint terminal 12D1 of the imaging chip 10 are joined. However, the junction terminal 12D1 is not connected to the light receiving unit 11. The junction terminal 12D1 (flying lead 23D1) may be connected to the light receiving unit 11 as long as it is one of two ground potential electrodes (potential lines), for example.

  The image pickup apparatus 1A has the effects of the image pickup apparatus 1 and can be used as a product even after performing a joint strength test that is a destructive test. The imaging apparatus 1 </ b> A can reliably ensure reliability by performing a 100% inspection of the bonding strength test. Further, the yield does not decrease even if a sampling test is performed.

  9 and 10, the flying lead 23 including the joint portion may be sealed with the sealing resin 40 after the test. Of course, even in the imaging apparatus 1 that has not been tested, the joints and the like may be sealed with the sealing resin 40.

  Further, when a cover glass is bonded so as to cover the light receiving portion 11 of the imaging chip 10, the sealing resin 40 may be sealed up to the side surface of the cover glass. A signal cable may be soldered to a connection electrode (not shown) at the other end of the wiring board 20. Furthermore, a prism or a lens may be bonded to the upper part of the light receiving unit 11 of the imaging chip 10 as an optical component.

  The imaging device 1B is joined to the wiring board 20 having a plurality of flying leads 23 respectively extended from the plurality of inner leads 21 disposed on the base film 22 and the tip of each flying lead 23. The plurality of junction terminals 12 includes the imaging chips 10 arranged on a straight line parallel to the end side, and protrudes from the notch portion 24 formed on the end side of the base film 22. The joint between the flying lead 23D1 and the joining terminal 12D1 that is longer than the flying lead is broken.

  However, since the flying lead 23D1 is a dummy lead in which a bonding failure with the bonding terminal 12D1 does not affect the input / output signal of the imaging chip 10, the imaging device 1A can be used as a product.

  Further, if at least one dummy lead 23D1 is used, the remaining long flying lead 23D for bonding strength test may be connected to the light receiving unit 11.

  Since the imaging device and the like of the above-described embodiment are small and suitable for small-quantity, multi-product production, the imaging device and the like can be used particularly for an imaging device or the like disposed at the distal end portion of an electronic endoscope.

  The present invention is not limited to the above-described embodiments and modifications, and various changes and modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 1A ... Imaging device, 10 ... Imaging chip, 11 ... Light-receiving part, 12, 12D ... Joint terminal, 13 ... Wiring, 20 ... Wiring board, 21, 21D ... Inner lead, 21A ... Land electrode, 23, 23D ... Flying Lead, 24 ... notch, 25 ... chip part, 26 ... protective layer, 30 ... hook, 40 ... sealing resin

Claims (10)

A wiring board having a plurality of flying leads respectively extended from a plurality of inner leads arranged on the base film, and a plurality of joining terminals joined to the front ends of the flying leads are straight lines parallel to the edges. An imaging device comprising: an imaging chip arranged in a row;
An imaging apparatus, wherein a joining between a flying lead that protrudes from a notch portion formed on an end side of the base film and is longer than another flying lead and a joining terminal is broken. A wiring board in which the tips of a plurality of flying leads including a flying lead that is longer than other flying leads, which are extended from an inner lead arranged on the base film, are on a straight line orthogonal to the extending direction;
An imaging device comprising: an imaging chip in which joining terminals each joined to the tip of the flying lead of the wiring board are arranged on a straight line parallel to the end side.   The length between the end surface of the cutout portion of the base film and the end surface of the imaging chip is 2 to 5 times the diameter of a hook of a jig for bonding strength test. Item 3. The imaging device according to Item 2. A flying lead that protrudes from the notch and is longer than other flying leads is a dummy lead for bonding strength test,
The imaging apparatus according to claim 3, wherein a bonding failure between the dummy lead and the bonding terminal does not affect an input / output signal of the imaging chip.   The imaging apparatus according to claim 4, wherein the outermost flying lead is the dummy lead. A step of producing an imaging chip in which a plurality of joining terminals are arranged on a straight line parallel to the end side;
A step of producing a wiring board in which inner leads are arranged on a base film;
When the end portion of the base film of the wiring board is selectively removed and the leading end portion of the inner lead becomes a flying lee protruding from the end side of the base film, a notch is formed. A step of forming a flying lead longer than the flying lead of
A method for manufacturing an imaging device, comprising: a step of joining a joining terminal of the imaging chip and a tip of a flying lead of the wiring board.   The length between the end surface of the cutout portion of the base film and the end surface of the imaging chip is 2 to 5 times the diameter of a hook of a jig for bonding strength test. Item 7. A method for manufacturing an imaging device according to Item 6. The flying lead that is longer than the other flying leads is a dummy lead for bonding strength test,
The method of manufacturing an imaging apparatus according to claim 7, wherein a bonding failure between the dummy lead and the bonding terminal does not affect an input / output signal of the imaging chip.   9. The method of manufacturing an imaging device according to claim 8, wherein the outermost flying lead is the dummy lead. It is the joining strength test method of the imaging device according to any one of claims 1 to 5,
A step of hooking a hook of a tensile test jig on the flying lead that is longer than the other flying leads;
And a step of measuring the strength of the joint by measuring the stress while pulling up the tensile test jig, and a method for testing the joint strength of the imaging apparatus.

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