JPH10267774A - Wafer of semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compact a semiconductor pressure sensor by forming on a wafer a resistance and an electrode pad for measuring a reverse direction characteristic of p-n junction between a gauge resistance and a diaphragm, and commonly using the pad. SOLUTION: A silicon wafer 4 comprises an element forming part 5 and an element non-forming part 6. Since a p-type resistance and a bonding pad 3 for measuring a reverse directional voltage-current characteristic, which are commonly used for measuring a reverse directional voltage-current characteristic of a plurality of semiconductor pressure sensors in the silicon wafer 4 are formed in the semiconductor pressure sensor forming region within the element forming part 5, there is no need of forming the p-type resistance and the bonding pad 3 for measuring a reverse directional voltage-current characteristic for every semiconductor pressure sensor as in the conventional arts, and the reverse directional voltage-current characteristic measurement can be implemented by the similar method to the conventional arts. Furthermore, the chip size of the semiconductor pressure sensor can be reduced and the number of the sensors cut from one silicon wafer 4 can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor wafer in which a plurality of semiconductor pressure sensors each having a gauge resistor and an electrode pad formed on the surface side of a diaphragm are formed.

[0002]

2. Description of the Related Art A semiconductor pressure sensor transmits a pressure to be detected as a strain to a silicon thin film of a diaphragm composed of a silicon thin film, changes a resistance value of a gauge resistor formed on the diaphragm, and converts this change into an electric signal. By detecting, the pressure is detected.

In this type of semiconductor pressure sensor, four gauge resistors are formed by diffusing or ion-implanting a p-type impurity such as silicon on a diaphragm formed on an n-type silicon substrate. A bridge circuit is formed by bridge-connecting the resistors, and a detection voltage corresponding to the measured pressure can be obtained as an output of the bridge circuit.

In such a semiconductor pressure sensor, the current applied to the bridge circuit usually flows through the gauge resistor, but the leak current (pn) between the gauge resistor and the diaphragm is generated.
The reverse current of the junction) causes errors in the measured pressure values. Therefore, in the manufacturing process of the semiconductor pressure sensor,
It is important to check the reverse voltage-current characteristics of the pn junction, and the quality of the semiconductor pressure sensor is determined based on the reverse voltage-current characteristics.

A specific example of a method for checking the reverse voltage-current characteristics is disclosed in Japanese Patent Application Laid-Open No. 61-733. That is, as shown in FIG. 4, one of the plurality of semiconductor pressure sensors 1 formed on a silicon substrate (silicon wafer) has a diaphragm 12 on an n-type silicon substrate (silicon wafer) 11. Four p-type gauge resistors (not shown) are formed on diaphragm 12
Are formed by diffusion or ion implantation, respectively. Each gauge resistor is bridge-connected to form a bridge circuit. On each gauge resistor, bonding pads (electrode pads) 13a to 13 made of Al electrodes for external electric measurement.
d is formed by vapor deposition or the like. Furthermore, the silicon substrate 1
On the outside of the diaphragm 12 in the effective area of the semiconductor pressure sensor 1 on the first, a p-type resistor (not shown) in the same manner as the gauge resistor and a bonding for measurement consisting of an Al electrode on the p-type resistor. Pad (electrode pad) 1
3e is formed, and the reverse voltage-current characteristics of the pn junction are measured using the p-type resistor and the bonding pad 13e. The p-type resistor is independent of the bridge circuit and has a floating island shape.

[0006] In the semiconductor pressure sensor 1 thus formed, as shown in FIG.
14d and a p-type resistor 14e, bonding pads 13a to 13
By applying a direct current from the measuring device 2 via d and the bonding pad 13e for measurement and measuring the leak current, the reverse voltage-current characteristics of the pn junction are measured.

[0007]

However, in the above-described semiconductor pressure sensor 1, the bonding pad 1 of the p-type resistor 14e for measuring the reverse voltage-current characteristics is used.
Since the area occupied by the semiconductor pressure sensor 3e in the semiconductor pressure sensor 1 is large, the semiconductor pressure sensor 1 itself becomes large, and there is a problem that it is difficult to reduce the size of the semiconductor pressure sensor 1.

The present invention has been made in view of the above points, and has as its object to form a semiconductor pressure sensor while forming a p-type resistor and an electrode pad for measuring reverse voltage-current characteristics. It is an object of the present invention to provide a semiconductor pressure sensor wafer that has been made smaller.

[0009]

According to a first aspect of the present invention, there is provided a semiconductor pressure sensor wafer having an element forming portion capable of forming a semiconductor pressure sensor and an element non-forming portion around the element forming portion. In a semiconductor pressure sensor wafer comprising: a semiconductor formed by forming a plurality of semiconductor pressure sensors in which a diaphragm serving as a pressure receiving portion is formed in the element forming portion, and a gauge resistor and an electrode pad are formed on the surface side of the diaphragm; In the pressure sensor wafer, a pair of resistance and electrode pads for measuring the reverse characteristics of the pn junction between the gauge resistance and the diaphragm are formed on the wafer, and the pn junction of the plurality of semiconductor pressure sensors is formed. In the measurement of the reverse characteristic, the electrode pad is shared.

According to a second aspect of the present invention, in the semiconductor pressure sensor wafer according to the first aspect, the electrode pad for measuring the reverse characteristics is formed in the element forming portion.

According to a third aspect of the present invention, in the semiconductor pressure sensor wafer according to the first aspect of the present invention, the electrode pad for measuring the reverse characteristics is formed in the non-element forming portion. .

According to a fourth aspect of the present invention, in the semiconductor pressure sensor wafer according to the first aspect, the electrode pad for measuring the reverse characteristics is formed on a side surface of the wafer. .

According to a fifth aspect of the present invention, in the semiconductor pressure sensor wafer according to the first aspect of the present invention, the electrode pad for measuring the reverse characteristic is formed in a portion corresponding to the element non-formation portion on the back surface of the wafer. It is characterized by having done.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a planar state of a wafer of a semiconductor pressure sensor according to an example of an embodiment of the present invention. Reference numeral 4 denotes a silicon wafer, which includes an element forming part 5 and an element non-forming part 6. The element forming section 5 is a region where a semiconductor pressure sensor can be formed. As shown in FIG. 2, a plurality of semiconductor pressure sensors 1 are formed via a dicing lane 7. The element non-forming portion 6 is a region on the outer peripheral portion of the element forming portion 5, and the semiconductor pressure sensor 1 is not formed.

The basic configuration of the semiconductor pressure sensor itself according to the present embodiment is the same as that described in the prior art, and therefore, the same portions are denoted by the same reference numerals and description thereof will be omitted. A feature of the present embodiment is that a set of a p-type resistor and a bonding pad (electrode pad) for measuring a reverse voltage-current characteristic is formed in the element forming section 5 of the semiconductor pressure sensor 1.
This is to measure reverse voltage-current characteristics of a plurality of semiconductor pressure sensors 1 using a set of p-type resistors and bonding pads. That is, as shown in FIG. 1, a plurality of semiconductor pressure sensors 1 are formed on a silicon wafer 4,
Dicing lane 7 between adjacent semiconductor pressure sensors 1
Are formed. Each semiconductor pressure sensor 1 formed on the silicon wafer 4 is separated by dicing along the dicing lane 4. Here, for one semiconductor pressure sensor in the element forming part 5,
A p-type resistor (not shown) for measuring reverse voltage-current characteristics and a bonding pad 3 (electrode pad) are formed.
The p-type resistor and the bonding pad 3 are formed in the same manner as the gauge resistors 13 to 16 and the bonding pads 23 to 26. No engraving of the diaphragm is formed in the portion where the p-type resistor (not shown) for measuring the reverse voltage-current characteristics and the bonding pad 3 are provided. In addition,
In this embodiment, the p-type resistor and the bonding pad 3 for measuring the reverse voltage-current characteristics are formed in the region of one semiconductor pressure sensor 1, but may be formed in a region larger than that.

For all the semiconductor pressure sensors 1 on the silicon wafer 4, a reverse voltage-
Using a p-type resistor and a bonding pad 3 for measuring current characteristics, reverse voltage-current characteristics are measured in the same manner as shown in FIG. After the measurement, each semiconductor pressure sensor 1 may be separated by dicing along the dicing lane 4.

As described above, according to the present embodiment, the common p for measuring the reverse voltage-current characteristics of the plurality of semiconductor pressure sensors 1 in the silicon wafer 4 is used for measuring the reverse voltage-current characteristics. Since the mold resistor and the bonding pad 3 are formed in the semiconductor pressure sensor forming area in the element forming portion 5 of the silicon wafer 4, the conventional semiconductor device is provided with a reverse voltage-current characteristic measurement for each semiconductor pressure sensor 1 as in the prior art. There is no need to form a p-type resistor and a bonding pad, so that the reverse voltage-current characteristics can be measured in the same manner as in the conventional case, and the chip size of the semiconductor pressure sensor 1 can be reduced. The number of pressure sensors 1 can be increased.

As another embodiment, a common p-type resistor and a bonding pad for measuring the reverse voltage-current characteristics of the semiconductor pressure sensor 1 in the silicon wafer 4 are used for measuring the reverse voltage-current characteristics. 3 may be formed in the element non-forming portion 6 of the silicon wafer 4 as shown in FIG. In the present embodiment, since the bonding pad 3 is formed in the element non-forming portion 6, the chip of the semiconductor pressure sensor 1 does not exist near the bonding pad 3, and the measurement at the time of measuring the reverse voltage-current characteristics is performed. There is no danger of probing of the pins, for example, the possibility of scratching by the measuring pins due to misalignment of the silicon wafer 4 or breakage of the chips of the semiconductor pressure sensor 1 due to incorrect positioning of the measuring pins, thereby improving the inspection yield. .

In still another embodiment, the bonding pads 3 may be formed on the side surfaces of the silicon wafer 4. In this case, a p-type resistor is formed near the side surface of the silicon wafer 4, and A
1 is deposited to make contact with a p-type resistor. This Al is stretched to the side surface of the silicon wafer 4 and connected to the bonding pad 3 formed on the side surface. When measuring the reverse voltage-current characteristics, the measurement is performed by bringing a wafer guide into contact with the bonding pad 3 formed on the side surface of the silicon wafer 4.

According to the present embodiment, since the bonding pad 3 as an electrode for measuring the reverse voltage-current characteristics is formed on the side surface of the silicon wafer 4, the area of the element formation portion 5 of the silicon wafer 4 is reduced. In addition to being able to be used to the maximum extent, it is not necessary to bring the measuring pins into contact with the measuring electrodes during the characteristic measurement, and the measurement can be performed simply by bringing the wafer guide into contact with the bonding pad 3.

In still another embodiment, a p-type resistor for measuring a reverse voltage-current characteristic and a bonding pad 3 as an electrode correspond to the element non-forming portion 6 on the front surface on the back surface of the silicon wafer 4. Form on the part. The p-type resistor and the bonding pad 3 correspond to the gauge resistors 13 to 16 and the bonding pads 23 to 2 on the surface of the silicon wafer 4.
6 may be formed by the same manufacturing method.

According to this embodiment, since the bonding pads 3 as measurement electrodes are formed on the back surface of the silicon wafer 4, the stage (stage) on which the silicon wafer 4 is mounted is used as a probe for measuring characteristics. This eliminates the need for measurement pins and measurement guides, and allows the connection of the bonding pad 3 as a measurement electrode and the stage as a probe to be performed simply by mounting the silicon wafer 4 on the stage. Simplification can be achieved.

[0023]

As described above, according to the first and second aspects of the present invention, an element forming portion capable of forming a semiconductor pressure sensor and an element non-forming portion around the element forming portion are provided. In a semiconductor pressure sensor wafer having
In the element forming portion, a diaphragm serving as a pressure receiving portion is formed, and a plurality of semiconductor pressure sensors formed by forming a gauge resistor and an electrode pad on the surface side of the diaphragm are formed on the wafer of the semiconductor pressure sensor. To
A pair of a resistor and an electrode pad for measuring the reverse characteristics of the pn junction between the gauge resistance and the diaphragm are formed, and the electrode pads are used for measuring the reverse characteristics of the pn junctions of the plurality of semiconductor pressure sensors. Since the electrodes are commonly used, an electrode pad for measuring the reverse direction characteristic is not provided for each of the plurality of semiconductor pressure sensors on the wafer, and a p-type resistor and an electrode pad for measuring the reverse direction voltage-current characteristic are used. It was possible to provide a semiconductor pressure sensor wafer that allowed the semiconductor pressure sensor to be downsized while being formed.

According to a third aspect of the present invention, in the first aspect of the present invention, if the electrode pad for measuring the reverse characteristic is formed in the element non-forming portion, a semiconductor pressure is present near the electrode pad. Trouble when probing measurement pins during measurement of reverse voltage-current characteristics when sensor chip does not exist, for example, a semiconductor pressure sensor due to scratches caused by measurement pins due to misalignment of the wafer or incorrect position of measurement pins This eliminates the risk of chip breakage and improves the inspection yield.

According to a fourth aspect of the present invention, in the first aspect of the present invention, if the electrode pad for measuring the reverse characteristics is formed on the side surface of the wafer, the area of the element forming portion of the wafer is reduced. In addition to maximally effective use, it is not necessary to contact a measurement pin with a measurement electrode at the time of characteristic measurement, and the measurement can be performed simply by bringing a wafer guide into contact with an electrode pad.

According to the fifth aspect of the present invention, in the first aspect of the present invention, the electrode pad for measuring the reverse characteristic is formed in a portion corresponding to the element non-formation portion on the back surface of the wafer. If the stage (stage) on which the wafer is mounted is used as a probe for measuring characteristics, pins for measurement and guides for measurement are not required, and the electrode pad and probe for measurement can be obtained simply by mounting the wafer on the stage. Can be connected, and the measurement work can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a wafer of a semiconductor pressure sensor according to one embodiment of the present invention.

FIG. 2 is an enlarged view according to the embodiment.

FIG. 3 is a schematic view showing a wafer of a semiconductor pressure sensor according to another embodiment of the present invention.

FIG. 4 is a schematic view showing one semiconductor pressure sensor in a wafer according to a conventional example.

FIG. 5 is an explanatory diagram showing a measurement state of a reverse voltage-current characteristic of a semiconductor pressure sensor.

[Explanation of symbols]

 Reference Signs List 1 semiconductor pressure sensor 2 measuring device 3 bonding pad (electrode pad) 4 wafer 5 element forming part 6 element non-forming part 7 dicing lane 11 silicon substrate 12 diaphragm 13a to 13d bonding pad (electrode pad) 13e bonding pad (electrode pad) 14a ~ 14d Gauge resistance 14ep p-type resistance

Claims (5)

[Claims] 1. A semiconductor pressure sensor wafer comprising: an element forming portion capable of forming a semiconductor pressure sensor; and an element non-forming portion around the element forming portion. The diaphragm that becomes the part is formed,
In a semiconductor pressure sensor wafer in which a plurality of semiconductor pressure sensors each having a gauge resistor and an electrode pad formed on the surface side of the diaphragm, a pn junction between the gauge resistance and the diaphragm is formed on the wafer. A semiconductor pressure sensor, wherein a pair of resistance and electrode pads for measuring directional characteristics are formed, and the electrode pads are shared when measuring the reverse characteristics of pn junctions of the plurality of semiconductor pressure sensors. Wafer. 2. An electrode pad for measuring reverse characteristics,
2. The device according to claim 1, wherein the device is formed in the element forming portion.
A wafer for the semiconductor pressure sensor as described in the above. 3. An electrode pad for measuring the reverse characteristic,
2. The device according to claim 1, wherein the device is formed in the element non-forming portion.
A wafer for the semiconductor pressure sensor as described in the above. 4. An electrode pad for measuring reverse characteristics,
2. The semiconductor pressure sensor wafer according to claim 1, wherein the wafer is formed on a side surface of the wafer. 5. An electrode pad for measuring reverse characteristics,
2. The semiconductor pressure sensor wafer according to claim 1, wherein the wafer is formed at a portion corresponding to the element non-formation portion on the back surface of the wafer.