JP4374029B2 - Semiconductor device with built-in contact sensor - Google Patents

Description

  The present invention relates to a semiconductor device, and more particularly to a semiconductor device in which a contact sensor such as a fingerprint sensor is incorporated.

  With the spread of electronic information communication, there is an increasing demand for personal recognition in electronic devices in order to protect the confidentiality of personal information. Various techniques have been developed and put into practical use as personal recognition means, and among them, techniques for discriminating fingerprints are attracting attention. As a small device for discriminating a fingerprint, a semiconductor device in which a contact type sensor using electrostatic capacitance is incorporated has been developed.

  Generally, a fingerprint sensor called an electrostatic type recognizes a fingerprint based on a change in capacitance by bringing a fingertip into direct contact with the surface of the sensor. A fingerprint sensor called a sweep type is a sensor that reads a fingerprint image by tracing (sweeping) the sensor surface with a finger. For example, a fingerprint image can be recognized by tracing the finger even with a width as small as about 1 mm. For this reason, the sweep type is mainly used as a fingerprint sensor incorporated in a small portable device or the like.

  A capacitance sensor serving as a fingerprint sensor can be formed on a silicon substrate in the same manner as a semiconductor element. That is, the fingerprint sensor can be manufactured as part of a semiconductor chip made from a silicon substrate.

  FIG. 1 is a side view of a state in which a sweep type fingerprint sensor device is incorporated in a housing of an electronic device. In FIG. 1, a bump 1 b of a flexible substrate 2 is connected to a semiconductor chip 1 with a built-in fingerprint sensor via an anisotropic conductive resin 4. The semiconductor chip 1 is incorporated in the housing 3 of the electronic device with the fingerprint sensor region 1b on the circuit forming surface 1a exposed. That is, since it is necessary to move while making a finger contact the fingerprint sensor region 1b, the fingerprint sensor region 1b is exposed to the outside.

  Since the fingerprint sensor region 1b is generally formed on the circuit forming surface 1a of the semiconductor chip 1, it is provided on the same surface as the bump 1c that is a mounting terminal for mounting the semiconductor chip 1 on the flexible substrate 2. In the case of the example shown in FIG. 1, the bumps 1 b formed to protrude from the circuit forming surface 1 a of the semiconductor chip 1 are connected to the electrode pads 4 a formed on the pattern wiring 4 of the flexible substrate 2, and the anisotropic conductive resin 5 It is fixed.

  In the configuration shown in FIG. 1, the fingerprint sensor region 1 b of the semiconductor chip 1 is a portion where a finger is directly contacted and must be exposed to the outside from the housing 3 of the electronic device to be incorporated.

  As described above, the fingerprint sensor unit 1a is a part that directly contacts with a finger. If the peripheral part of the exposed part is high, there is a possibility that the finger cannot be completely contacted. In particular, in the case of a sweep type fingerprint sensor device, the width (in the X direction in FIG. 1) of the fingerprint sensor region 1b is as small as about 1 mm. Therefore, the end portion of the flexible substrate 2 is not covered with the housing 3 and is exposed to the outside.

  As described above, when the end portion of the flexible substrate 2 is exposed, an external force may act on the end portion. For example, when the finger is moved in the opposite direction (the direction opposite to the X direction) when the finger is brought into contact with the fingerprint sensor region 1b, a force that lifts the end of the flexible substrate 2 may be applied. .

The end portion of the flexible substrate 2 is a connection portion with the semiconductor chip 1. When a force that lifts the end portion is applied as described above, the end of the flexible substrate 2 is weak when the bonding force by the anisotropic conductive resin 5 is weak. There is a possibility that the portion may be peeled off from the semiconductor chip 1. In this case, the electrical connection between the semiconductor chip 1 and the flexible substrate 2 becomes poor, and the problem that the fingerprint sensor does not function arises. The present invention has been made in view of the above points. It is an object of the present invention to provide a semiconductor device with a built-in contact sensor in which a connection portion with a substrate is protected.

In order to achieve the above-described object, according to one embodiment of the present invention, a built-in contact type sensor having a sensor region formed on a circuit forming surface and a connection electrode provided in a region other than the sensor region. includes a semiconductor element and a wiring board connected to the connection electrodes of the semiconductor element, the end face of the wiring board, Ri inclined surfaces der inclined with respect to the circuit formation surface of the semiconductor element, the tip A contact-type sensor built-in semiconductor device is provided, wherein the portion is located on the circuit formation surface of the semiconductor element .

  According to the above-described embodiment of the present invention, the end surface of the wiring board located on the circuit formation surface of the semiconductor element is inclined, and the force acting on the end surface causes the end portion of the wiring board to move to the circuit formation surface of the semiconductor element. It will not be in the direction of pulling away from. Thereby, peeling of the edge part of a wiring board is prevented and the failure of a semiconductor device by peeling of a wiring board can be prevented.

  Next, embodiments of the present invention will be described with reference to the drawings.

  First, a fingerprint sensor device according to a first embodiment of the present invention will be described with reference to FIGS. 2A and 2B are views showing a fingerprint sensor device according to a first embodiment of the present invention, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view. FIG. 3 is an enlarged view of a portion A in FIG.

  The fingerprint sensor device shown in FIG. 2 includes a semiconductor chip 1 in which a fingerprint sensor is built in, and a flexible substrate 2 as a wiring substrate for connecting the semiconductor chip 1 to an external circuit. A fingerprint sensor region 1b is formed on the circuit forming surface 1a of the semiconductor chip 1, and bumps 1c are formed on portions other than the fingerprint sensor region 1b. The bump 1 c is connected to the electrode pad 4 a formed on the pattern wiring 4 of the flexible substrate 2 via an anisotropic conductive resin 5. The anisotropic conductive resin 5 may be a resin such as NCP (non-conductive paste).

  The semiconductor chip 1 is incorporated into the casing of the electronic device with the fingerprint sensor region 1b exposed. That is, since it is necessary to move while making a finger contact the fingerprint sensor region 1b, the fingerprint sensor region 1b is exposed to the outside.

  Since the fingerprint sensor region 1b is formed on the circuit forming surface 1a of the semiconductor chip 1, it is provided on the same surface as the bump 1c that is a mounting terminal for mounting the semiconductor chip 1 on the flexible substrate 2. In the case of the example shown in FIG. 2, the bumps 1 c formed to protrude from the circuit formation surface 1 a of the semiconductor chip 1 are connected to the electrode pads 4 a formed on the pattern wiring 4 of the flexible substrate 2, and the anisotropic conductive resin 5 Bonded and fixed.

The flexible substrate 2 is obtained by attaching a copper foil to an insulating base material 6 such as a polyimide film and patterning it to form a pattern wiring 4 and an electrode pad 4a. The semiconductor chip 1 is mounted on one end of the flexible substrate 2, and the connector connecting portion 2a to the external circuit is formed on the other end. The fingerprint sensor device having the above-described configuration is the fingerprint sensor region 1b of the semiconductor chip 1. Is incorporated in a state of being exposed from the casing of the electronic device, and is connected to an internal circuit of the electronic device via the flexible substrate 2. At this time, the end portion of the flexible substrate 2 connected to the semiconductor chip as described above is also exposed from the casing of the electronic device.

  In this embodiment, a protective resin is applied to the exposed end portion of the flexible substrate 2 to form the protective resin portion 7. The protective resin is made of, for example, a liquid epoxy resin, and is applied and cured so as to cover the end surface 2b of the flexible substrate 2 and the surface near the end surface. Therefore, the end surface 6 a of the base 6 of the flexible substrate 2 is protected by the protective resin portion 7, and no external force acts near the end surface 6 a of the base 6.

  As described above, in this embodiment, since the exposed end portion of the flexible substrate 2 is protected by the protective resin portion 7, no external force acts on the end portion of the flexible substrate 2 when the finger is brought into contact with the fingerprint sensor region 1b. , Peeling of the end portion can be prevented. Therefore, it is possible to prevent poor electrical connection due to peeling of the end portion, and to maintain the fingerprint sensor function for a long time.

  Next, a manufacturing method of the above-described fingerprint sensor device will be described with reference to FIGS. FIG. 4 is a diagram illustrating a process of connecting a semiconductor chip to the flexible substrate 2 to obtain a fingerprint sensor device. FIG. 5 is a side view of a cutting tool used in the cutting step in FIG. 4, and FIG. 6 is an enlarged view of a portion C in FIG. 4A to 4D, the upper side is a plan view, and the lower side is a cross-sectional view along the line AA in the plan view. Also in FIG. 5, the diagram shown on the upper side is a plan view, and the diagram shown on the lower side is a cross-sectional view along the line AA in the plan view.

  In the manufacturing process shown in FIG. 4, three flexible substrates 2 are manufactured from one base material sheet. First, as shown in FIG. 4A, the base sheet 6A is patterned by pressing or etching to create a schematic shape of the flexible substrate 2. At this stage, the three flexible substrates 2 are partially connected to the base sheet 6A.

  Next, as shown in FIG. 4B, the semiconductor chip 1 is connected to each of the three flexible substrates 2. At this time, the base sheet 6A is placed on the bonding stage 10 as shown in FIGS. 5 and 6, and the semiconductor chip 1 is placed thereon so that the bumps 1c and the electrode pads 4a are in contact with each other. . Then, the bonding tool 11 is pressed from the back surface of the semiconductor chip 1 to bond the bump 1c and the electrode pad 4a. At this time, the anisotropic conductive resin 5 is filled between the semiconductor chip 1 and the flexible substrate 2, and the flexible substrate 2 and the semiconductor chip are bonded to increase the bonding reliability.

  Here, since the bump 1c is provided only on one side of the semiconductor chip, the semiconductor chip 1 is inclined. Therefore, the surface of the bonding stage 10 on which the semiconductor chip 1 is placed is not flat, and the step 10a is provided so that the side of the semiconductor chip 1 where the bump 1c is not provided is higher by the height of the bump 1c. As a result, the semiconductor chip 1 is placed in parallel to the bonding stage, and good bonding can be performed.

  Next, as shown in FIG. 4C, the protective resin portion 7 is formed by applying a protective resin to the end portion of the flexible substrate 2 on the side where the semiconductor chip 1 is connected. When applying the protective resin, it is necessary to apply an appropriate amount so that the protective resin sufficiently covers the end portion of the flexible substrate 2 and does not cover the fingerprint sensor region 1b of the semiconductor chip 1.

  When the protective resin is cured, as shown in FIG. 4D, the portion where each flexible substrate 2 is connected to the base sheet 6A is cut to separate the flexible substrate 2 from the base sheet 6A, thereby completing the fingerprint sensor device. To do.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is an enlarged side view of a part of the fingerprint sensor device according to the second embodiment of the present invention. 7, parts that are the same as the parts shown in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted.

  In the second embodiment of the present invention, instead of forming the protective resin portion 7 in the above-described first embodiment, the filling amount of the anisotropic conductive resin 5 is increased, and is intentionally protruded. That is, when the semiconductor chip 1 is connected to the flexible substrate 2, the amount of the anisotropic conductive resin 5 filled between the semiconductor chip 1 and the flexible substrate 2 is increased to cover the end surface of the base 6 of the flexible substrate 2. Keep it protruding. Thereby, the edge part of the flexible substrate 2 is reinforced with the anisotropic conductive resin 5, and peeling of an edge part is prevented.

  Next, a fingerprint sensor device according to a third embodiment of the present invention will be described with reference to FIGS. 8A and 8B are views showing a fingerprint sensor device according to a third embodiment of the present invention, in which FIG. 8A is a plan view and FIG. 8B is a cross-sectional view. FIG. 9 is an enlarged view of a portion B in FIG. FIG. 10 is a diagram for explaining that the static electricity on the fingertip is removed. 8 to 10, parts that are the same as the parts shown in FIGS. 2 and 3 are given the same reference numerals, and descriptions thereof will be omitted.

  The fingerprint sensor device according to the third embodiment of the present invention includes a semiconductor chip 1 and a flexible substrate 2A connected to the semiconductor chip 1 in the same manner as the fingerprint sensor device shown in FIG. The flexible substrate 2A is obtained by adding a ground conductive portion 12 to the flexible substrate 2 described above. That is, the ground conductive portion 12 is formed on the surface of the base 6 so as to cover the end of the flexible substrate 2 on the side where the semiconductor chip 1 is connected. The ground conductive portion 12 is provided on the surface opposite to the pattern wiring 4, and is connected to the ground wiring of the pattern wiring 4 through the through hole 23. Therefore, the grounding conductive portion 12 is grounded through the pattern wiring 4.

  The portion where the ground conductive portion 12 is formed is the portion where the finger first comes into contact when the finger is brought into contact with the fingerprint sensor region 1b. Accordingly, as shown in FIG. 10, since the fingertip is electrically connected to the grounding portion of the electronic device through the through hole 13 and the pattern wiring 4 at the moment when the fingertip touches the grounding conductive portion, the static electricity accumulated on the fingertip. Flows to the grounding part of the electronic device. Thereby, the static electricity is removed before the fingertip contacts the fingerprint sensor region 1b, and it is possible to prevent the static electricity from acting on the fingerprint sensor region 1b. The fingerprint sensor is generally a sensor using a capacitance sensor, and is particularly worried about the influence of static electricity. However, by removing the static electricity as in this embodiment, malfunction and damage of the fingerprint sensor device due to static electricity are prevented. be able to.

  In this embodiment, since the ground conductive portion 12 is provided on the semiconductor chip side of the flexible substrate 2, the protective resin portion 7 as shown in FIG. 3 cannot be formed. Therefore, in this embodiment, as shown in FIG. 9, the end (end face) of the flexible substrate 2 </ b> A is inclined so that an external force that separates the flexible substrate 2 from the semiconductor chip 1 does not act. Yes.

  That is, the end surface 6a of the base 6 of the flexible substrate 2A is inclined rather than perpendicular to the circuit forming surface 1a of the semiconductor chip 1 so that the fingertip is not easily caught and the end portion is always the semiconductor chip even when the fingertip touches it. It is comprised so that it may be pressed toward.

  As a processing method for providing an inclination to the end face 6a of the base material 6, there is a processing method for processing the base material 6 from the ground conductive portion 12 side by etching. That is, the inclined end face 6a is naturally formed by removing the base material 6 from the grounding conductive part 12 side by contacting with the etching solution. However, it is preferable that the pattern wiring 4 is etched from the opposite side to provide an inclination opposite to the end face 6a. Thus, the anisotropic conductive resin 5 is configured to be filled up to the boundary between the base material 6 and the pattern wiring 4 to prevent the lower end portion of the flexible substrate 2A from protruding.

  As described above, in this embodiment, the flexible substrate is prevented from peeling by providing an inclination at the end portion of the flexible substrate, and the ground conductive portion is formed on the surface side of the end portion of the flexible substrate. Static electricity is effectively removed.

  In the above-described embodiment, as shown in FIG. 11, fillet-shaped portions of anisotropic conductive resin 5 (or non-conductive paste) are formed at corners formed by the semiconductor chip 1 and the flexible substrate 2. It is good as well. By forming such a fillet-shaped portion, it is possible to prevent the flexible substrate 2 from being easily detached from the semiconductor chip 1 even when a tensile force acts on the flexible substrate 2 as shown in FIG. Further, as shown in FIG. 13, a fillet-shaped portion made of a protective resin 14 different from the anisotropic conductive resin 5 may be formed at a corner portion formed by the semiconductor chip 1 and the flexible substrate 2.

It is a side view of a state in which a sweep type fingerprint sensor device is incorporated in a casing of an electronic device. It is a figure which shows the fingerprint sensor apparatus by 1st Example of this invention, (a) is a top view, (b) is sectional drawing. It is an enlarged view of the A section in Fig.2 (a). It is a figure explaining the process of connecting a semiconductor chip to a flexible substrate, and setting it as a fingerprint sensor apparatus. It is a side view of the cutting tool used in the cutting process in FIG. It is an enlarged view of the C section in FIG. FIG. 6 is an enlarged side view of a part of a fingerprint sensor device according to a second embodiment of the present invention. It is a figure which shows the fingerprint sensor apparatus by 3rd Example of this invention, (a) is a top view, (b) is sectional drawing. It is an enlarged view of the B section in Fig.8 (a). It is a figure for demonstrating that the static electricity of a fingertip is removed. It is a side view which shows the example which formed the fillet-shaped part between the flexible substrate and the semiconductor chip. It is a figure for demonstrating the effect of the fillet shape part shown in FIG. It is a side view which shows the modification of the fillet shape part shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor chip 1a Circuit formation surface 1b Fingerprint sensor area | region 1c Bump 2,2A Flexible substrate 4 Pattern wiring 4a Electrode pad 5 Anisotropic conductive resin 6 Base material 6a End surface 7 Protection resin part 10 Bonding stage 11 Bonding tool 12 Ground conductive part 13 Through hole 14 Protective resin

Claims (2)

A contact sensor built-in semiconductor element having a sensor region formed on a circuit forming surface and a connection electrode provided in a region other than the sensor region;
And a wiring board which is connected to the connection electrodes of the semiconductor element,
The end face of the wiring board, the contact-type sensor Ri inclined surfaces der inclined, its tip, characterized in that positioned on the circuit formation surface of the semiconductor element to the circuit forming surface of the semiconductor element Built-in semiconductor device. It is a semiconductor device with a built-in contact type sensor according to claim 1,
A conductive portion is formed on the surface of the wiring board opposite to the surface facing the semiconductor element, in the vicinity of the inclined surface, and the conductive portion is electrically connected to the grounding wiring in the wiring. A semiconductor device with a built-in contact sensor.

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