JP4441483B2 - Fingerprint sensor device - Google Patents

Description

  The present invention relates to a fingerprint sensor device, and more particularly to a fingerprint sensor device packaged with a fingerprint sensor element formed on a semiconductor element exposed on the surface.

  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.

The fingerprint sensor device is a device for recognizing a fingerprint pattern of a human finger. In order to develop a small fingerprint sensor device, a semiconductor chip for a fingerprint sensor in which a fingerprint sensor portion is formed on a semiconductor chip has been developed. The fingerprint sensor unit is generally composed of a pressure sensor and a capacitance sensor, and information from the sensor unit is processed by a semiconductor chip to identify and determine a fingerprint. Such a semiconductor chip for a fingerprint sensor is resin-sealed and packaged like a general semiconductor chip, and is incorporated into an electronic device as a semiconductor device for a fingerprint sensor.

  FIG. 1 is a cross-sectional view showing a resin sealing process in a manufacturing process of a conventional fingerprint sensor device. The semiconductor element 2 for fingerprint sensor has a sensor portion 4 on a circuit forming surface, and an electrode is disposed around the sensor portion. The electrode is wire-bonded to an electrode pad 8a of a circuit board 8 as an interposer by a gold wire 6 or the like. On the circuit board 8, the semiconductor chip 2 and the gold wire are molded with a sealing resin to form the sealing resin portion 10.

  The sensor unit 4 is a part that directly touches a finger to recognize a fingerprint, and needs to be exposed from the sealing resin unit 10. Therefore, as shown in FIG. 1, when the semiconductor chip 2 is molded with the molding die 12, the spacer 14 is disposed between the molding die 12 and the sensor unit 4 so that the sealing resin is on the surface of the sensor unit 4. The spacer 12 is pressed against the sensor unit 4 so as not to cover.

  The spacer 12 is formed of a material having elasticity to some extent, such as rubber or plastic, and is pressed against the sensor unit 4 by the mold 12. This prevents the sealing resin from flowing into the surface of the sensor unit 4 during molding.

  In the method of exposing the sensor unit 4 by pressing the spacer 14 during resin molding as described above, if the spacer unit 14 is not elastic to some extent, the sensor unit 4 is pressed against the sensor unit 4. 4 may be damaged. However, if the sensor unit 4 has elasticity, the sealing resin enters between the sensor unit 4 and the spacer 14 due to the resin pressure at the time of molding.

  FIG. 2 is a cross-sectional view of the fingerprint sensor device molded with the sealing resin entering between the sensor portion 4 and the spacer 14. An opening 10a of the sealing resin portion 10 is formed at a portion where the spacer 14 is disposed at the time of resin molding, and the sensor portion 4 is exposed in the opening 10a.

  However, as shown in FIG. 2, the sealing resin that has entered between the sensor unit 4 and the spacer 14 becomes a mold flash 16 and adheres to the surface of the sensor unit 4. For this reason, a part of the surface of the sensor unit 4 is covered with the mold flash 16, and the part loses the function as the sensor unit. That is, the area of the portion that functions as the sensor unit 4 is reduced.

  In the case of a so-called area type fingerprint sensor in which the area of the sensor unit 4 is relatively large, since the ratio of the sensor unit covered with the mold flash is small, the function of the sensor unit can be maintained in the remaining part. However, in the case of a so-called sweep type fingerprint sensor that moves so as to wipe the sensor unit 4 with a finger and reads a fingerprint, the width H of the sensor unit 4 is as very small as 1 mm, for example. In general, the length L of the mold flash is 0.3 mm to 0.5 mm, and most of the sensor unit 4 is covered with the mold flash and may not function as the sensor unit.

  In the case of a sweep type fingerprint sensor, if the height of the resin around the exposed portion of the sensor unit 4 is high (that is, if the opening 10a is deep), the finger is wiped while the finger is in contact with the sensor unit 4 There is also a problem that it becomes difficult to move (sweep).

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a fingerprint sensor device that can easily move a finger by suppressing the height of the resin portion around the sensor portion in a sweep type fingerprint sensor. And

  In order to solve the above-described problems, the present invention is characterized by the following measures.

The invention according to claim 1 is a fingerprint sensor device for recognizing a fingerprint pattern by moving while a finger is in contact with a semiconductor chip having a sensor portion formed on the surface, and sealing the semiconductor chip A sealing resin portion, wherein the sensor portion and the surface of the semiconductor chip are exposed at a bottom portion of the opening portion formed in the sealing resin portion, and the opening portion defines the opening portion. portion in a direction to move out fingers, the plane der in the same plane as the exposed surface of the semiconductor chip is, the upper surface of the sealing resin portion is higher than the surface of the semiconductor chip, the and the opening the It is formed on the upper surface of the sealing resin portion .

  A second aspect of the present invention is the fingerprint sensor device according to the first aspect, wherein a part of the sealing resin portion straddles a boundary between the exposed surface of the semiconductor chip and the flat surface of the sealing resin portion. As described above, protrusions are formed along the boundary.

  According to a third aspect of the present invention, there is provided a fingerprint sensor device for recognizing a fingerprint pattern by moving with a finger in contact with a semiconductor chip having a sensor portion formed on the surface, and sealing the semiconductor chip A sealing resin portion, wherein the sensor portion and the surface of the semiconductor chip are exposed at a bottom portion of the opening portion formed in the sealing resin portion, and the opening portion defines the opening portion. Of these, the portion in the direction of moving the finger is lower than the other portions but higher than the exposed surface of the semiconductor chip.

  According to the first aspect of the present invention, when there is no sealing resin portion that hinders movement when moving (scanning) while bringing a finger into contact with the sensor portion, fingerprint recognition is smoothly performed. It is possible to maintain recognition with high accuracy.

  According to the second aspect of the present invention, since the end portion of the semiconductor chip is covered by the protrusion of the sealing resin portion, it is possible to protect the end portion of the semiconductor chip that is likely to be chipped or broken.

  According to the invention of claim 3, since the portion in the direction of moving the finger in the sealing resin portion is formed lower than the other portion, when moving (scanning) while bringing the finger into contact with the sensor portion, Fingerprint recognition can be performed smoothly, and highly accurate recognition can be maintained.

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

  FIG. 3 is a cross-sectional view of the fingerprint sensor device according to the first embodiment of the present invention. 3, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted.

  The fingerprint sensor device according to the first embodiment of the present invention has a fingerprint sensor shown in FIG. 2 in that it has an opening 18 larger than the opening 10a formed on the upper surface of the sealing resin portion 10 of the fingerprint sensor device shown in FIG. Is different.

  The basic structure of the fingerprint sensor device shown in FIG. 3 is the same as that of the fingerprint sensor shown in FIG. 2, and the semiconductor chip 2 fixed on the circuit board via the die attachment material 22 is made of sealing resin. Molded. An opening 18 is formed in the sealing resin portion 10, and the sensor portion 4 of the semiconductor chip 2 is exposed on the bottom surface of the opening 18.

  FIG. 4 is a cross-sectional view showing a step of resin-sealing the semiconductor chip 2 in the manufacturing process of the fingerprint sensor device shown in FIG. The opening 18 of the sealing resin portion 10 is formed by disposing the spacer 20 in the mold. The fingerprint sensor device according to the present embodiment has a planar shape of, for example, 4.5 mm × 14 mm, and the planar shape of the semiconductor chip 2 is 3 mm × 13 mm. And the sensor part 4 is formed in the elongate area | region about 1 mm in width. 3 and 4 is shown as a cross section in the width direction.

  As shown in FIG. 4, when the semiconductor chip 2 is resin-sealed, a spacer 20 is attached to the mold 12 and the spacer 20 is disposed between the mold 12 and the sensor unit 4. The portion where the sealing resin does not flow in due to the spacer 20 becomes the opening portion 18 of the sealing resin portion 10. When the sealing resin portion is taken out from the mold 12, the opening portion 18 is formed in the portion where the spacer is present. The sensor unit 4 is exposed at the bottom.

  The spacer 20 is formed of an elastic material such as a heat-resistant plastic such as polyimide or a heat-resistant rubber such as silicon rubber, and is attached to a predetermined portion of the mold 12 in advance. The depth of the opening 18 of the resin sealing portion 10 is about 0.2 mm, and the thickness of the spacer 20 is set to a value slightly larger than 0.2 mm in consideration of the compressibility.

  Here, the width of the spacer 20 (the dimension in the same direction as the width direction of the sensor unit) is about twice the width of the sensor unit 4. Therefore, in the width direction of the sensor unit 4, peripheral portions of the sensor unit 4 are exposed on both sides thereof. Specifically, the dimension of the spacer 20 in the width direction is such that the distance S between one end of the sensor section 4 in the width direction and one end of the spacer is 0.3 mm to 1.0 mm as shown in FIG. Is set.

  Even when the opening 18 is formed by the spacer 20 having the above dimensions, mold flash as shown in FIG. 2 may occur. However, as described above, the length of the mold flash is about 0.3 mm to 0.5 mm from the end of the spacer. Therefore, even if a mold flash occurs, the mold flash is connected to the sensor unit 4 as shown in FIG. Never reach. Therefore, it is prevented that the sensor unit 4 is covered with the mold flash 16 and the function as the sensor unit is impaired.

  Since the width of the semiconductor chip is about 4 mm, the electrodes of the semiconductor chip 2 formed on the same surface as the sensor unit 4 are resin-sealed when the distance S is a large value exceeding 1 mm. Will not be able to. Based on such dimensional constraints, the distance S is preferably set to 0.3 mm to 1.0 mm.

  Here, the starting point of the distance S is defined as the position of the bottom end of the opening 18 corresponding to the end of the spacer 20, that is, the end of the bottom of the opening 18 when mold flash does not occur. The

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a cross-sectional view of a fingerprint sensor device according to a second embodiment of the present invention, and FIG. 6 is a cross-sectional view showing a step of resin-sealing the semiconductor chip 2 in the manufacturing process of the fingerprint sensor device shown in FIG. .

  The fingerprint sensor device according to the second embodiment of the present invention has the same configuration as the fingerprint sensor device according to the first embodiment shown in FIG. 3, but the shape of the opening formed in the resin sealing portion is different. In this embodiment, the shape of the opening has a step at the bottom as shown in FIG. 5, and a step 18A having a height of 70 μm to 150 μm is formed around the surface where the sensor unit 4 is exposed.

  In order to form the stepped portion 18A, the spacer 20A may be formed in a two-step shape as shown in FIG. That is, the surface of the upper step of the spacer 20A is pressed in contact with the sensor unit 4, and the surface around the upper step is at a position 70 μm to 150 μm lower. When resin molding is performed using such a spacer 20A, the sealing resin flows into a gap G of 70 μm to 150 μm formed between the lower step and the upper surface of the semiconductor chip 2, and the step portion shown in FIG. 18A is formed.

  Here, when the sealing resin flows into the gap G, since the gap G is small, the inflowing pressure rapidly decreases, and when reaching the deepest part of the gap, that is, near the end of the sensor part 4, the pressure is very high. It becomes weak and cannot enter between the spacer 20 </ b> A and the sensor unit 4. Therefore, occurrence of mold flash can be prevented.

  If the width of the gap G, that is, the height of the stepped portion 18A from the sensor portion 4, is too small, the sealing resin does not flow in. If it is too large, the pressure loss is reduced and mold flash occurs. In the case of a sealing resin used in a normal transfer mold, if the gap G is 70 μm to 150 μm as described above, the sealing resin is the deepest part of the gap while moderately reducing the pressure of the sealing resin flowing into the gap G. Can be reached. Therefore, the entire surface of the semiconductor chip 2 can be resin-sealed while leaving the sensor portion 4 without causing mold flash on the bottom surface of the opening 18 of the sealing resin portion 10.

  Next, a fingerprint sensor device according to a third embodiment of the present invention is described. The fingerprint sensor device according to the third embodiment particularly relates to a sweep type fingerprint sensor. First, a sweep type fingerprint sensor will be described with reference to FIG.

  A sweep type fingerprint sensor device is a sensor that recognizes a fingerprint pattern by moving a part with a fingerprint such as a finger in contact with the sensor part. Capacitance sensors are used as sensor units, and individual fingerprint patterns are recognized by processing the change data of capacitance due to the movement of the concave and convex portions of the fingerprint when the finger is moved (when the finger is swept). To do. Therefore, if the height around the opening from which the sensor unit is exposed is large, it becomes difficult to move the finger while contacting the sensor unit. For this reason, it is preferable that at least the peripheral portion in the finger movement direction (scanning direction) of the periphery of the opening is as low as possible.

  FIG. 8 is a cross-sectional view of a fingerprint sensor device according to a third embodiment of the present invention, and FIG. 9 is a cross-sectional view showing a step of resin-sealing the semiconductor chip 2 in the manufacturing process of the fingerprint sensor device shown in FIG. . 8 and 9, parts that are the same as the parts shown in FIGS. 5 and 6 are given the same reference numerals, and descriptions thereof will be omitted.

  The sweep type fingerprint sensor according to the third embodiment of the present invention is resin-sealed with the surface of the semiconductor chip 2 exposed on the downstream side of the sensor unit 4 in the scanning direction. That is, the semiconductor chip 2 is resin-sealed in a state where the periphery of the opening 18B on the downstream side in the scanning direction of the sensor unit 4 is removed. Note that a protective film is preferably formed in advance on the exposed portion of the upper surface of the semiconductor chip.

  As shown in FIG. 9, the above-described opening 18 </ b> B can be formed by attaching a spacer 24 that extends downstream in the scanning direction of the sensor unit 4 to the mold 12. The spacer 24 has a shape that covers the upper surface of the resin-sealed semiconductor chip 2 and extends further downstream. Therefore, when scanning a finger during fingerprint recognition, the finger can move smoothly without any resistance, and fingerprint recognition accuracy is improved.

  FIG. 10 is a cross-sectional view showing a modification of the fingerprint sensor device according to the third embodiment, and FIG. 11 is a cross-sectional view showing a step of resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. It is.

  The fingerprint sensor device shown in FIG. 10 is provided with a protruding portion 26 formed by slightly protruding the sealing resin at the boundary portion between the semiconductor chip 2 and the sealing resin portion 10. As shown in FIG. 11, the protrusion 26 can be easily formed by providing a cutout corresponding to the shape of the protrusion in a part of the spacer 24. The protrusion 26 is provided at a position that covers the end of the semiconductor chip 2, and functions to prevent the end of the semiconductor chip 2 from being chipped or damaged.

  Next, a fingerprint sensor device according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a cross-sectional view of a fingerprint sensor device according to a fourth embodiment of the present invention. 13 is a cross-sectional view showing a preparation process before resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10, and FIG. 14 is a manufacturing process of the fingerprint sensor device shown in FIG. It is sectional drawing which shows the process of resin-sealing a semiconductor chip.

  The fingerprint sensor device according to the fourth embodiment of the present invention has a configuration in which a part of the surface of the semiconductor chip 2 is exposed as in the fingerprint sensor device shown in FIG. 8, and the sensor unit 4 can be easily scanned with a finger. ing. However, in this embodiment, the sealing resin portion 10 is set slightly higher than the exposed surface of the semiconductor chip 2 in order to protect the end portion of the semiconductor chip 2.

  In order to make the surface of the sealing resin portion 10 slightly higher than the surface of the semiconductor chip 2, first, as shown in FIG. 13, a protective tape 30 is attached to the upper surface of the semiconductor chip 2 before resin sealing. The material of the protective tape 30 is preferably the same material as the above-mentioned spacer. Then, as shown in FIG. 14, resin molding is performed in a state in which the protective tape 30 is pasted over the sensor unit 4 and the surface to be exposed of the semiconductor chip 2. By peeling off the protective tape 30 after molding, the fingerprint sensor device shown in FIG. 12 is obtained. Therefore, a height difference corresponding to the thickness of the protective tape 30 is generated between the upper surface of the sealing resin portion 10 and the upper surface of the semiconductor chip 2. Thereby, the edge part of the semiconductor chip 2 can be protected.

  Further, a photosensitive resin may be applied over the upper surface of the semiconductor chip 2 and the sensor unit 4 instead of the protective tape 30. That is, as shown in FIG. 15, a photosensitive resin film 32 is formed on the sensor unit 4 and the surface to be exposed of the semiconductor chip 2. The photosensitive resin film 32 can be formed using a technique of patterning and etching a resist, such as that used in semiconductor chip manufacturing techniques.

  Then, as shown in FIG. 16, resin molding is performed in a state where the photosensitive resin film 32 is formed over the sensor portion 4 and the surface to be exposed of the semiconductor chip 2. After the molding, as shown in FIG. 17, the photosensitive resin film 32 is removed by exposure and cleaning, and the fingerprint sensor device shown in FIG. 12 is obtained. Therefore, a difference in height corresponding to the thickness of the photosensitive resin film 32 occurs between the upper surface of the sealing resin portion 10 and the upper surface of the semiconductor chip 2. Thereby, the edge part of the semiconductor chip 2 can be protected.

It is sectional drawing which shows a resin sealing process in the manufacturing process of a fingerprint sensor apparatus. It is sectional drawing of the fingerprint sensor apparatus molded in the state in which sealing resin entered between the sensor part and the spacer. 1 is a cross-sectional view of a fingerprint sensor device according to a first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a step of resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 3. It is sectional drawing of the fingerprint sensor apparatus by 2nd Example of this invention. FIG. 6 is a cross-sectional view showing a step of resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 5. It is sectional drawing for demonstrating a sweep type fingerprint sensor apparatus. It is sectional drawing of the fingerprint sensor apparatus by 3rd Example of this invention. FIG. 9 is a cross-sectional view showing a step of resin-sealing the semiconductor chip 2 in the manufacturing process of the fingerprint sensor device shown in FIG. 8. It is sectional drawing which shows the modification of the fingerprint sensor apparatus by 3rd Example of this invention. FIG. 11 is a cross-sectional view showing a step of resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10. FIG. 6 is a cross-sectional view of a fingerprint sensor device according to a fourth embodiment of the present invention. FIG. 11 is a cross-sectional view showing a process of attaching a protective tape before resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10. FIG. 11 is a cross-sectional view showing a step of resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10. FIG. 11 is a cross-sectional view showing a step of forming a photosensitive resin film before resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10. FIG. 11 is a cross-sectional view showing a step of resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10. FIG. 11 is a cross-sectional view showing an exposure process after resin-sealing a semiconductor chip in the manufacturing process of the fingerprint sensor device shown in FIG. 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Semiconductor chip 4 Sensor part 6 Gold wire 8 Circuit board 12 Mold die 16 Mold flash 18 Opening part 18A Step part 20, 20A, 24 Spacer 22 Die attachment material 26 Protrusion part 30 Protective tape 32 Photosensitive resin film

Claims (3)

A fingerprint sensor device for recognizing a fingerprint pattern by moving while touching a finger,
A semiconductor chip having a sensor portion formed on the surface, and a sealing resin portion for sealing the semiconductor chip;
The surface of the sensor part and the semiconductor chip is exposed at the bottom of the opening formed in the sealing resin part, and the part of the sealing resin part that defines the opening in the direction of moving a finger is , the plane der in the same plane as the exposed surface of the semiconductor chip is, the upper surface of the sealing resin portion is higher than the surface of the semiconductor chip, the and the opening formed on the upper surface of the sealing resin portion fingerprint sensor apparatus characterized by being. The fingerprint sensor device according to claim 1,
A fingerprint sensor device, wherein a protrusion is formed along the boundary as a part of the sealing resin portion across the boundary between the exposed surface of the semiconductor chip and the flat surface of the sealing resin portion. A fingerprint sensor device for recognizing a fingerprint pattern by moving while touching a finger,
A semiconductor chip having a sensor portion formed on the surface, and a sealing resin portion for sealing the semiconductor chip;
The surface of the sensor part and the semiconductor chip is exposed at the bottom of the opening formed in the sealing resin part, and the part of the sealing resin part that defines the opening in the direction of moving a finger is The fingerprint sensor device is lower than other portions but higher than the exposed surface of the semiconductor chip.

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