JPH04332871A - Semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To enable wire bonding property to be improved by reducing a mounting area to a package and then increasing a degree of freedom of a layout of a bonding pad. CONSTITUTION:A title item is provided with a sensor chip 1 which is formed by performing three-dimensional machining of a semiconductor substrate, stoppers 3 and 2 which are provided at upper and lower sides of the sensor chip 1 for preventing damage of a weight portion of this sensor chip 1 due to excessive vibration, and a signal-processing chip 4 which is provided at the upper-side stopper 3 for processing an output signal of the sensor chip 1. Also, a bonding pad 7 and an alumina wiring 9 are formed on an upper portion of the upper-side stopper 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor acceleration sensor, and more particularly to a semiconductor acceleration sensor in which a sensor chip and a signal processing chip are stacked.

0002

2. Description of the Related Art Conventionally, this type of semiconductor acceleration sensor has a sensor chip and a signal processing chip for processing output signals mounted on the same plane of a substrate, and the two are connected by aluminum wiring.

FIG. 4 is a plan view of a conventional semiconductor acceleration sensor. As shown in FIG. 4, the conventional semiconductor acceleration sensor has a sensor chip 1 with a stopper 3 bonded to it mounted on a ceramic substrate 12 or the like, and a signal processing circuit chip 4 mounted near the sensor chip 1. The sensor chip 1 and the signal processing chip 4 are connected by bonding pads 13 and wiring 14 deposited on a ceramic substrate 12. Furthermore, the pads 13 are connected to the pads 8 on the sensor chip 1 and the signal processing chip 4 by bonding wires 5, respectively.

FIG. 5 is a sectional view of another conventional semiconductor acceleration sensor. As shown in FIG. 5, this sensor has stoppers 3 and 2 bonded to the top and bottom of a sensor chip 1, and a signal processing chip 4 is mounted on top of the top stopper 3 to process the output signal of the sensor. are doing. For electrical connection between the sensor chip 1 and the signal processing circuit 4, a bonding wire 5 is directly connected from a bonding pad 8 on the sensor chip 1 to a bonding pad 15 on the signal processing chip 4. Note that the sensor chip 1 has a weight portion 6 with both sides formed in the center by three-dimensional processing, and is laminated with the stoppers 2 and 3 in a sandwich manner.

[0005]

The conventional semiconductor acceleration sensor described above has the disadvantage that the mounting area increases because the sensor chip and the signal processing circuit chip are arranged side by side. In addition, if a signal processing circuit chip is mounted on top of the sensor chip, there is no problem in terms of mounting area, but in terms of wire bonding, the bonding pads should be separated sufficiently so that the wires do not touch the chip end face. There is a drawback that setting the wire bonder is difficult due to the necessity and the large step difference between the first and second wires.

An object of the present invention is to provide a semiconductor acceleration sensor that reduces the mounting area in such a package and improves wire bonding properties.

[0007]

[Means for Solving the Problems] A semiconductor acceleration sensor according to a first aspect of the invention includes a sensor chip formed by three-dimensional processing of a semiconductor substrate, and a sensor chip formed by three-dimensionally processing a semiconductor substrate. It has stoppers provided above and below the sensor chip, and a signal processing chip provided on the upper stopper for processing the output signal of the sensor chip, and a bonding pad and aluminum wiring are provided above the upper stopper. It is composed by forming.

Further, the semiconductor acceleration sensor of the second invention includes a sensor chip formed by three-dimensional processing of a semiconductor substrate, and an upper part of the sensor chip to prevent the weight part of the sensor chip from being destroyed due to excessive vibration. and a stopper provided on the lower side, and a signal processing chip provided on the upper stopper for processing the output signal of the sensor chip, and a bonding pad formed on the upper part of the upper stopper and the signal processing chip. It is constructed by bonding the bonding pads of the signal processing circuit using a bump method.

[0009]

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

FIG. 1 is a sectional view of a semiconductor acceleration sensor showing one embodiment of the present invention. As shown in FIG. 1, this embodiment includes a sensor chip 1 having a weight portion 6 formed by three-dimensional processing, and stoppers 3 and 2 bonded to the upper and lower parts of the sensor chip 1, respectively. These stoppers 2 and 3 are provided to prevent the weight portion 6 of the sensor chip 1 from being displaced more than necessary due to vibration and being destroyed. That is, a certain gap (for example, 3 to 20 μm) is formed between the stoppers 2 and 3 and the sensor chip 1, and the center portion of the sensor chip 1 is prevented from being displaced beyond this gap. Furthermore, a signal processing chip 4 is mounted on the upper stopper 3. Electrical connections between these members are made by connecting pads placed on the stopper 3, pads on the signal processing chip 4, and pads on the sensor chip 1 using bonding wires 5, respectively.

FIG. 2 is a plan view of the sensor shown in FIG. 1. As shown in FIG. 2, the signal processing chip 4 of the sensor is mounted on the upper stopper 3, as described above.
Similarly, a bonding pad 7 and an aluminum wiring 9 are also formed on the upper stopper 3. Electrically, the bonding pad 8 of the sensor chip 1 and the bonding pad 7 of the upper stopper 3 are connected by a bonding wire 5. Further, the bonding pad 7 is connected to a bonding pad attached to the upper surface of the signal processing chip 4 via an aluminum wiring 9. Thereby, the signal detected by the bridge resistor (not shown) in the sensor chip 1 is processed by the signal processing chip 4, and the result is output to the outside.

FIG. 3 is a sectional view of a semiconductor acceleration sensor showing another embodiment of the present invention. As shown in FIG. 3, the difference between this embodiment and the above-mentioned embodiment is that the signal processing chip 4 is bonded to the upper stopper 3 by a bump method (flip chip method). . In FIG. 3, a stopper 2 is attached to the lower part of the sensor chip 1, and a stopper 3 is attached to the upper part of the sensor chip 1.
The output of is connected by a wire 5 to the upper stopper 3. This output signal is connected to a bump bonding pad 10 at a predetermined position by wiring on the stopper 3. Moreover, the bump bonding pad 1 on the stopper 3
0 and a bump bonding pad 10 on the signal processing chip 4 are bonded to each other by a bump 11. This bump 11
As a result, the signal of the sensor chip 1 is transmitted to the signal processing chip 4, and the signal processing chip 4 is fixed on the stopper 3.

[0013]

Effects of the Invention As explained above, the semiconductor acceleration sensor of the present invention reduces the mounting area on the package and improves the bonding pad layout compared to the conventional structure in which the signal processing circuit is mounted on the stopper. This has the effect of increasing the degree of freedom and improving wire bonding properties.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor acceleration sensor showing an embodiment of the present invention.

FIG. 2 is a plan view of the sensor shown in FIG. 1;

FIG. 3 is a sectional view of a semiconductor acceleration sensor showing another embodiment of the present invention.

FIG. 4 is a plan view of a semiconductor acceleration sensor showing a conventional example.

FIG. 5 is a sectional view of another conventional semiconductor acceleration sensor.

[Explanation of symbols]

1 Sensor chips 2, 3 Stopper 4 Signal processing chip 5 Bonding wire 6 Weight portions 7, 8 Bonding pad 9 Aluminum wiring 10 Bump bonding pad 11
bump

Claims (2)

[Claims] 1. A sensor chip formed by three-dimensional processing of a semiconductor substrate; stoppers provided on the upper and lower sides of the sensor chip to prevent a weight portion of the sensor chip from being destroyed due to excessive vibration; A semiconductor acceleration sensor comprising: a signal processing chip provided on the upper stopper for processing an output signal of the sensor chip; and a bonding pad and aluminum wiring formed on the upper part of the upper stopper. 2. A sensor chip formed by three-dimensional processing of a semiconductor substrate; stoppers provided on the upper and lower sides of the sensor chip to prevent a weight portion of the sensor chip from being destroyed due to excessive vibration; and a signal processing chip provided on the upper stopper to process the output signal of the sensor chip, and the bonding pad formed on the upper part of the upper stopper and the bonding pad of the signal processing circuit of the signal processing chip are connected by bumping. A semiconductor acceleration sensor characterized by being bonded by.