JP2001124794A - Mounting structure of micro-machined sensor and mounting method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure and a mounting method of a micro-machined sensor that uses a general inexpensive resin substrate as a substrate and absorbs stress due to a difference in thermal expansion without increasing a wire bond to a high step. To provide. SOLUTION: In a mounting structure for mounting a micro-processed sensor 1 on a substrate 14, micro-processes are formed on an upper surface of a base 10 having upper and lower wirings 11 conducting between the upper and lower surfaces and bumps 12 formed on the lower surface in contact with the upper and lower wires. The sensor 1 is mounted, and the signal output terminal 7 of the micro-processed sensor 1 and the base 1
The base 1 on which the microfabricated sensor 1 is mounted by connecting the upper and lower electrodes 11 of the upper and lower wirings 11 by wire bonds 8
0 is mounted on the substrate 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mounting structure of a micromachined sensor such as a semiconductor pressure sensor and a semiconductor acceleration sensor, and a mounting method thereof.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional mounting structure of a micro-machined sensor 1 such as a semiconductor pressure sensor or a semiconductor acceleration sensor. Here, a description will be given by taking a semiconductor acceleration sensor as an example of the microfabricated sensor 1.

[0003] The semiconductor acceleration sensor includes a weight portion 2 that is displaced during acceleration, a bending portion 3 connected to the weight portion 2,
Some flexures 3 have a piezoresistor 4 for detecting a distortion generated in the flexure 3 due to the displacement of the weight 2, and detect acceleration based on a change in resistance of the piezoresistance 4. Upper and lower stoppers 5 and 5 made of glass material serving to limit displacement of the weight portion 2 and prevent breakage of the flexure portion 4 when excessive acceleration occurs at the upper and lower portions of the weight portion 2 and the flexure portion 3. 6 are provided. This lower stopper 6
The chip portion forming the weight portion 2 and the bending portion 3 also serves as a glass pedestal. A signal output terminal unit 7 for outputting an acceleration signal detected by a change in resistance of the piezo resistor 4 to the outside is connected to an electrode 15 of a wiring pattern on a wiring board by a wire bond 8.

Although a semiconductor pressure sensor is not shown, a method of detecting a pressure by a change in piezoresistance is used similarly to a semiconductor acceleration sensor. Further, a glass pedestal having a pressure introducing hole (corresponding to the lower stopper 6 of the lower semiconductor acceleration sensor) is provided below the semiconductor pressure sensor chip. That is, the basic structure is similar to the semiconductor acceleration sensor.

When such a micro-processed sensor 1 is mounted on a wiring board by COB (chip on board), a stress is generated due to a difference in thermal expansion between the micro-processed sensor 1 and the wiring board, and a sensing portion of the micro-processed sensor 1 is generated. The effect on is a problem. In particular, it affects the bending portion 4,
This becomes an error factor for acceleration detection and the like.

As a countermeasure against the difference in thermal expansion, a ceramic substrate 18 having a small difference in thermal expansion is used as a wiring board.
The stress is absorbed by using a silicon paste 16 having a high elastic modulus as a die bond material for bonding the microfabricated sensor 1 and the wiring substrate.

[0007]

However, the ceramic substrate 18 is expensive, and if a general inexpensive resin substrate is used, the thermal expansion difference between the resin substrate and the microfabricated sensor is large and a strong stress is generated. 16 alone cannot absorb the stress sufficiently. As a countermeasure, it is conceivable to increase the thickness of the silicon paste 16 or the thickness of the glass pedestal (corresponding to the lower stopper 6). However, there is a new problem that the wire bond 18 becomes a high step and the yield decreases.

The present invention has been made in view of the above circumstances, and has as its object to use a general inexpensive resin substrate as a wiring board, and to make a difference in thermal expansion difference without increasing a wire bond to a high step. It is an object of the present invention to provide a mounting structure of a micro-machined sensor and a mounting method thereof, which absorb a stress caused by a micro sensor.

[0009]

In order to achieve the above object, an invention according to claim 1 is directed to a mounting structure for mounting a micro-machined sensor such as a semiconductor pressure sensor or a semiconductor acceleration sensor on a substrate. The upper and lower wirings that are conductive, and the upper surface of a base on which bumps that are in contact with the upper and lower wirings are formed on the lower surface, the micromachining sensor is mounted. An electrode unit is connected by wire bonding, and the base on which the micro-processed sensor is mounted is mounted on the substrate.

According to a second aspect of the present invention, in the mounting structure of the micro-processed sensor according to the first aspect, the micro-processed sensor is a semiconductor acceleration sensor, and the base detects acceleration in the semiconductor acceleration sensor. It is characterized in that it also serves as a stopper for suppressing excessive swing of the weight portion.

According to a third aspect of the present invention, in the method for manufacturing a mounting structure of a micro-machined sensor according to the first aspect, the base and the micro-machined sensor are bonded with an adhesive, and then a signal of the micro-machined sensor is provided. The output terminal portion and the electrode portion of the upper and lower wirings on the upper portion of the base are connected by wire bonding, and then the base on which the microfabricated sensor is mounted is mounted on the substrate, and the bumps on the lower portion of the base are mounted on the substrate. The bump is mounted so as to be located on the electrode of the wiring pattern, and then the bump is melted and mounted by reflow heating.

According to a fourth aspect of the present invention, in the method of manufacturing a mounting structure for a micro-machined sensor according to the second aspect, the chip portion, which is the main body portion of the semiconductor acceleration sensor, and the base are anodically bonded. The signal output terminal section of the micro-machined sensor and the upper and lower wiring electrodes on the base are connected by wire bonding, and then the base on which the micro-machined sensor is mounted is mounted on the substrate, The bump is mounted so as to be positioned on an electrode of the wiring pattern of the substrate, and then the bump is melted and mounted by reflow heating.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mounting structure and a mounting method of a micro-machined sensor according to an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a side view showing a mounting structure of a micro-machined sensor according to a first embodiment of the present invention. A resin substrate 14 is used as a wiring substrate on which the micro-processed sensor 1 is mounted. Although the micro-machined sensor 1 (semiconductor acceleration sensor in the figure) is originally mounted on this substrate, a glass base 10 is provided therebetween in the present invention. The glass base 10 has a wiring pattern.
And the upper and lower wiring 1 on the lower surface of the glass base 10.
Bumps 12 (such as solder bumps) that are electrically connected to 1
Is formed. The microfabricated sensor 1 is mounted on a glass base 10 using a silicon paste 16. The glass base 10 on which the microfabricated sensor 1 is mounted is mounted on the resin substrate 14 so that the bumps 12 coincide with the electrodes 15 of the wiring pattern on the resin substrate 14, and electrical connection is made by the bumps 12. Further, in the present embodiment, an underfill resin is filled between the resin substrate 14 and the glass base 10 and is hardened to enhance strength and environmental resistance.

Here, the signal output terminal portion 7 of the micro-machined sensor 1 is connected to the electrode portion 13 electrically connected to the upper and lower wirings 11 on the upper surface of the glass base 10 by wire bonds 8. That is, the signal output terminal section 7 is
Wire bonding to the electrode portion 13 of the glass base 10 instead of to the electrode 15 of FIG. Therefore, the signal output terminal 7
Sensor signal (acceleration detection signal in this case) output from
Is guided to the electrode 15 on the resin substrate 14 through the wire bond 8, the electrode portion 13 on the glass base 10, the upper and lower wirings 11 in the glass base 10, and the bump 12.

As described above, when mounting the microfabricated sensor 1 on the resin substrate 14, the mounting structure is provided with the glass base 10 interposed therebetween, so that the stress caused by the difference in thermal expansion is reduced by the glass base 10. This has the effect of being performed. Further, since the wire bond 8 is also formed on the electrode portion 13 on the glass base 10, there is an effect that the yield of wire bonding can be prevented from deteriorating without a high step.

FIG. 2 is a side view showing a mounting structure of a micro-machined sensor according to a second embodiment of the present invention. The basic structure is a structure in which a glass base 10 is interposed as in the first embodiment.
Is also used as a stopper (lower stopper 6) for suppressing excessive swing of the weight portion 2 for detecting acceleration in the semiconductor acceleration sensor (micro-processing sensor 1). The wire bond 8 is similarly connected to the electrode section 11 on the glass base 10 (lower stopper 6).

Since the glass base 10 also serves as the lower stopper 6, the number of steps can be reduced and the cost can be reduced, and the step of the wire bond 8 can be further reduced. This has the effect of improving the performance and improving the yield.

FIG. 3 shows a third embodiment of the present invention.
It is a process drawing showing the 1st manufacturing method of the mounting structure of a micromachining sensor. Upper and lower wiring 11 and upper and lower wiring 11 inside
The microfabricated sensor 1 is mounted on a glass base 10 having an electrode portion 13 on an upper part and a bump 12 on a lower part of an upper and lower wiring 11 using a silicon paste 16 (a). Next, the signal output terminal portion 7 of the micro-processed sensor 1 is formed by wire bonding 8.
And the electrode unit 13 on the glass base 10 are connected (b).
Next, the glass base 10 on which the microfabricated sensor 1 is mounted
Is mounted on the resin substrate 14 such that the bumps 12 are aligned with the electrodes 15 of the wiring pattern on the resin substrate 14 (c). Then, the bumps 12 are melted by the reflow heat treatment, and the upper and lower wirings 11 are electrically connected to the wiring patterns on the resin substrate. Finally, the resin substrate 14 and the glass base 10
Fill the underfill resin 17 between and cure it,
Increase strength and environmental resistance.

FIG. 4 shows a fourth embodiment of the present invention.
It is a flowchart showing the 2nd manufacturing method of the mounting structure of a micromachining sensor. This is a manufacturing method according to the mounting structure of the second embodiment. Upper and lower wiring 11 inside,
The micro-machined sensor 1 (semiconductor acceleration sensor) without the lower stopper 6 is mounted on the glass base 10 having the electrode portion 13 above the upper and lower wirings 11 and the bump 12 below the upper and lower wirings 11, and the micro-machined sensor is formed by anodic bonding. 1 and the glass base 10 are connected. Here, the glass base 10
Also functions as the lower stopper 6 (a). Next, the signal output terminal portion 7 of the micro-processed sensor 1 is formed by wire bonding 8.
And the electrode unit 13 on the glass base 10 are connected (b).
Next, the glass base 10 on which the microfabricated sensor 1 is mounted
Is mounted on the resin substrate 14 such that the bumps 12 are aligned with the electrodes 15 of the wiring pattern on the resin substrate 14 (c). Then, the bumps 12 are melted by the reflow heat treatment, and the upper and lower wirings 11 are electrically connected to the wiring patterns on the resin substrate. Finally, the resin substrate 14 and the glass base 10
Fill the underfill resin 17 between and cure it,
Increase strength and environmental resistance.

The embodiment of the present invention has been described above. In the present invention, a glass base having upper and lower wirings 11 is used. However, there is a glass with a metal wire manufactured by HOYA, and this glass is cut and the glass base 1 of the present invention is cut.
If 0 is used, the mounting structure of the present invention can be realized at low cost.

[0022]

As described above, according to the first aspect of the present invention, in a mounting structure for mounting a microfabricated sensor such as a semiconductor pressure sensor or a semiconductor acceleration sensor on a substrate, the upper and lower surfaces for conducting between the upper surface and the lower surface are provided. Wiring and, on the upper surface of the base on which the bumps in contact with the upper and lower wirings are formed on the lower surface, the micromachining sensor is mounted. Are connected by wire bonds, and the base on which the micro-machined sensor is mounted is mounted on the substrate, so that stress caused by a difference in thermal expansion during mounting can be reduced by the glass base, and A low-cost resin substrate can be used, and since the wire bonds are made to the electrodes on the glass base, the wire bonding can be performed without a high step. Mounting structure of a micro-machined sensor that can prevent the yield degradation could be provided.

According to the second aspect of the present invention, the first aspect is provided.
In the mounting structure of the invention described above, the microfabricated sensor is a semiconductor acceleration sensor, and the base also serves as a stopper that suppresses excessive swing of a weight portion that detects acceleration in the semiconductor acceleration sensor. Therefore, there is an effect that the cost can be further reduced.

According to the third aspect of the present invention, the base and the microfabricated sensor are adhered to each other with an adhesive, and then a signal output terminal of the microfabricated sensor and an electrode portion of upper and lower wirings provided on the base. Are connected by wire bonding, and then the base on which the microfabricated sensor is mounted is mounted on the substrate so that the bumps on the lower part of the base are located on the electrodes of the wiring pattern of the substrate, Since the bumps are melted and mounted by reflow heating, there is an effect that the mounting structure of the present invention can be easily realized.

In the invention according to claim 4, the chip portion, which is the main body portion of the semiconductor acceleration sensor, is anodically bonded to the base, and then the signal output terminal portion of the micro-machined sensor and the upper part of the base are provided. The electrode portions of the upper and lower wirings are connected by wire bonding, and then the base on which the microfabricated sensor is mounted is placed on the substrate, and the bumps on the base are positioned on the electrodes of the wiring pattern on the substrate. Since the mounting is performed and then the bumps are melted and mounted by reflow heating, the mounting structure of the present invention can be easily realized and the number of steps can be further reduced.

[Brief description of the drawings]

FIG. 1 is a side view showing a mounting structure of a micro-machined sensor according to a first embodiment of the present invention.

FIG. 2 is a side view showing a mounting structure of a micro-machined sensor according to a second embodiment of the present invention.

FIG. 3 is a process chart showing a first manufacturing method of a mounting structure of a micro-machined sensor as a third embodiment of the present invention.

FIG. 4 is a process chart showing a second method of manufacturing a mounting structure of a micro-machined sensor as a fourth embodiment of the present invention.

FIG. 5 is a side view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Micro processing sensor 6 Glass pedestal (semiconductor acceleration sensor lower stopper) 7 Signal output terminal part 8 Wire bond 10 (Glass) base 11 Upper and lower wiring 12 Bump 13 (Upper and lower wiring) Electrode part 14 Resin substrate 15 (Wiring pattern) electrode 16 Silicon paste 17 Underfill resin 18 Ceramic substrate

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 29/84 H01L 23/12 L W (72) Inventor Ryoji Saijo 1048 Odakadoma, Kadoma City, Osaka Matsushita Electric Works, Ltd. (72) Inventor Hiroshi Saito 1048 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Sumio Akai 1048 Kadoma, Kazuma, Kadoma, Osaka Prefecture F-term (reference) 2F055 AA40 BB20 CC02 CC12 DD04 DD07 FF21 FF23 FF43 GG14 4M112 AA02 CA31 CA33 DA13 DA18 EA13 EA14 GA01 5F044 AA10

Claims (4)

[Claims] In a mounting structure for mounting a microfabricated sensor such as a semiconductor pressure sensor or a semiconductor acceleration sensor on a substrate, a base having an upper and lower wiring conducting between an upper surface and a lower surface and a bump formed on the lower surface in contact with the upper and lower wiring is formed. The base on which the micro-fabricated sensor is mounted, and the signal output terminal portion of the micro-fabricated sensor is connected to the upper and lower wiring electrodes on the base by wire bonding, and the micro-fabricated sensor is mounted. Is mounted on the substrate. 2. The semiconductor device according to claim 1, wherein the micro-machining sensor is a semiconductor acceleration sensor, and the base is also used as a stopper for suppressing an excessive deflection of a weight detecting an acceleration in the semiconductor acceleration sensor. The mounting structure of the microfabricated sensor according to claim 1. 3. The base and the microfabricated sensor are bonded with an adhesive, and then the signal output terminal of the microfabricated sensor and the upper and lower wiring electrodes on the base are connected by wire bonding. Then, the base on which the micro-processed sensor is mounted is mounted on the substrate so that the bumps at the lower part of the base are located on the electrodes of the wiring pattern of the substrate,
2. The method according to claim 1, wherein the bump is melted and mounted by reflow heating. 4. A chip, which is a main body of the micro-machined sensor, and the base are anodically bonded. Next, a signal output terminal of the micro-machined sensor and an electrode of upper and lower wirings on the base are connected. Connected by wire bond, and then mounted the base on which the micro-processed sensor was mounted on the substrate such that the bumps under the base were positioned on the electrodes of the wiring pattern of the substrate, and then reflow heating was performed. 3. The method according to claim 2, wherein the bump is melted and mounted.
The mounting method of the microfabricated sensor described.