JPH0534371A - Measuring apparatus for sensitivity of semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To measure sensitivity from a sensor output when a specified flow rate of air is blow against a chip to be inspected in a wafer. CONSTITUTION:This apparatus is made up of a means 3 (31-34) which blows a specified flow rate of air against a chip 10 to be inspected having a cantilever 11 in a wafer 1, a means 4 which is connected to a chip to be inspected through a probe and performs an electric processing of a change in the resistance value of a strain gauge resistor 12 of the chip to be inspected to obtain a sensor sensitivity and a means 5 which determines a sensor sensitivity by a data processing of the sensor output to evaluate the sensor sensitivity. In the measurement of the sensor sensitivity. air is blown to the cantilever by controlling the necessary flow rate thereof so that the sensor output of the chip to be inspected be within an allowable range preset from the measurement results with a master chip. A sensor output voltage is extracted from the change in the resistance value corresponding to the current deformation value of the cantilever and it is judged whether the voltage value is within an allowable range preset to determine the propriety of an acceleration sensor.

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 sensitivity measuring device for measuring sensor sensitivity in a wafer state.

[0002]

2. Description of the Related Art A semiconductor acceleration sensor is provided with a strain gauge resistor diffused and formed on a silicon single crystal substrate and a diaphragm or a cantilever for applying mechanical stress to the strain gauge resistor, and acceleration is applied to the substrate. Then, the resistance value of the strain gauge resistor changes, and a sensor output corresponding to the change is obtained. In a semiconductor acceleration sensor, variations in sensor characteristics occur due to uneven resistance values of strain gauge resistors and uneven thickness of diaphragms and the like.
Therefore, an adjustment resistor is connected to a bridge circuit formed by a strain gauge resistor, and the resistance value of the adjustment resistor is changed from the measurement result of the electrical characteristics for adjustment. Further, the quality of the semiconductor acceleration sensor is determined by actually applying acceleration during acceleration or deceleration and determining whether or not the sensor output measured at that time is within an allowable range. Further, as a method for verifying the characteristics of the pressure sensor in a wafer state, Japanese Patent Laid-Open Publication No. 6-86
The one described in 2-32332 is known.

[0003]

As described above, since the semiconductor acceleration sensor is inspected in the state where the sensor chip is incorporated, there is a problem that the device for accelerating and decelerating becomes large-scale. An object of the present invention is to provide a sensitivity measuring device for a semiconductor acceleration sensor, which measures the sensitivity from the sensor output when a predetermined flow rate of air is blown on a wafer-state verification chip.

[0004]

In order to achieve the above object, a semiconductor acceleration sensor sensitivity measuring apparatus according to the present invention is a semiconductor acceleration sensor sensitivity measuring apparatus for measuring sensor sensitivity in a wafer state. Means for blowing a predetermined flow rate of air to the assay chip having a cantilever and the assay chip are connected via a probe, and the resistance value change of the strain gauge resistor of the assay chip is electrically processed to obtain a sensor output. And means for processing the sensor output to obtain the sensor sensitivity and evaluating the sensor sensitivity.

[0005]

The air flow rate required for the sensor output of the verification chip to fall within the preset allowable range is determined from the measurement result of the master chip, and the predetermined air flow rate is blown to the cantilever of the verification chip. As a result, the cantilever is deformed, and the resistance value of the strain gauge resistor changes. A sensor output is obtained by electrically processing the resistance value change corresponding to the deformation amount of the cantilever. Then, the sensor sensitivity is obtained from the sensor output, and it is determined whether or not this value is within a preset allowable range to determine the quality of the semiconductor acceleration sensor.

[0006]

EXAMPLES Examples of the present invention will be described. FIG. 1 shows a circuit configuration of a sensitivity measuring device for a semiconductor acceleration sensor. FIG. 2 is a conceptual diagram for explaining the sensitivity measurement of the semiconductor acceleration sensor. In this embodiment, the semiconductor acceleration sensor will be described by using a semiconductor acceleration sensor having a cantilever. The sensitivity measuring device controls the air flow rate for blowing a predetermined flow rate of air to each of the cantilevers 11 and 21 of one sensor chip of the silicon wafer 1 (hereinafter referred to as “verification chip 10”) and the standard master chip 2. A probe is connected to the control device 3 and the strain gauge resistors 12 and 22 of the verification chip 10 and the master chip 2, and the resistance value change taken out through this probe is electrically processed, and the sensor output by the master chip 2 and The sensor output device 4 for obtaining the sensor output from the verification chip 10 and the air flow rate blown by the air flow rate control device 3 are adjusted based on the sensor output from the master chip 2, and the sensor output of the verification chip 10 based on this air flow rate is adjusted in advance. The evaluation chip is evaluated by determining whether it is within the set tolerance range, and the evaluation data is evaluated. A data processing device 5 that outputs data, an output device 6 that prints or displays the result of quality determination sent from the data processing device, and evaluation data such as basic data of determination of quality and determination result data. The storage device 7 stores the data.

The air flow rate control device 3 adjusts the pressurized air supplied from the air source 31 to a constant pressure by the pressure regulator 32, and adjusts the pressure-adjusted air to the flow rate control valve 3
The flow rate is controlled to 3 at a predetermined flow rate, and control is performed to spray the cantilever 11, 21 of the verification chip 10 or the master chip 2 from the nozzle via the switching valve 34. The air flow rate blown onto the verification chip 10 is determined from the air flow rate required for the sensor output obtained by the strain gauge resistor 22 of the master chip 2 to fall within a preset allowable range. The sensor output device 4 is connected to a plurality of assay chips on a silicon wafer by a probe, processes an electrical signal from each assay chip obtained by scanning the assay chip through the probe, and detects a sensor output. , And sends the detected sensor output to the data processing device 5.

The silicon wafer 1 is set on the mounting table,
A nozzle that is movable in three dimensions is arranged on the mounting table. Therefore, the cantilever 1 of an arbitrary assay chip 10 can be operated without moving the silicon wafer 1.
Nozzles can be fitted over 1. The distance from the assay chip can be changed by moving the nozzle in the vertical direction. A plurality of sensor chips 10 are manufactured on the silicon wafer 1 by a semiconductor manufacturing technique, and one sensor chip 10 has a cantilever 11 having a cantilever structure and a stress strain caused by vibration of the cantilever 11 as shown in FIG. The strain gauge resistor 12 is provided so as to be diffused and formed at a portion (root portion of the cantilever) where the strain is generated. The cantilever 11 has a thin portion 11a extending from the chip substrate 10a formed by anisotropic etching, and a thick portion 11b serving as a weight portion provided continuously to the thin portion 11a, and the thin portion 11a and the chip substrate are provided. A strain gauge resistor 12 is arranged at the root of the cantilever, which is the connection part of the. On the chip substrate 10a near the strain gauge resistor 12, an external processing circuit, in this case, a pad 10 for connecting to the sensor output device 4 via a probe.
b is provided, and the pad 10b and the strain gauge resistor 12 are provided.
The wiring 10c is provided between the line and.

Next, the sensitivity measurement of the semiconductor acceleration sensor will be described. FIG. 3 shows the relationship between the sensor output voltage Vout (mV) and the spraying flow rate (l / min) by the master chip. FIG. 4 shows a flowchart of sensitivity measurement. First,
In the measurement of the master chip, a predetermined flow rate of air is blown to the master chip, and the cantilever of the master chip is deformed according to the air volume. The sensor output at this time is read and processed by the data processing device to determine the air flow rate required for the sensor output of the verification chip to fall within a preset allowable range (S1). The air flow rate control device controls the flow rate control valve so as to supply the determined air flow rate (S2).
Then, the nozzle is set on the assay chip (S3), and the assay chip is measured (S4). At this time, it is judged whether or not the sensor output is within the permissible range. If the sensor output is within the permissible range, the result is passed, and if it is out of the permissible range, the process is rejected (S
5). In this way, the result of the quality judgment of the test chip is output such as printout or display (S6). Further, the evaluation data of each assay chip is stored (S7). Then, the process returns to S3, and the next assay chip is measured.

[0010]

As described above, according to the present invention, since an external force can be applied to the verification chip in the silicon wafer state, it is possible to perform mechanical trimming with an external resistance adjusting resistor so that the required output sensitivity is obtained. Become. Further, since a predetermined flow rate of air is blown to the verification chip to exert an external force, the external force can be easily adjusted by controlling the flow rate, and the device configuration is simple.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a sensitivity measuring device for a semiconductor acceleration sensor showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a sensor chip, FIG. 2A is a sectional view, and FIG. 2B is a plan view.

FIG. 3 is a diagram showing a relationship between a sensor output voltage and a blowing flow rate.

FIG. 4 is a flowchart of sensitivity measurement of a semiconductor acceleration sensor.

[Explanation of symbols]

 1 Silicon Wafer 2 Master Chip 3 Air Flow Control Device 4 Sensor Output Device 5 Data Processing Device 6 Output Device 7 Storage Device 10 Verification Chip 31 Air Source 32 Pressure Regulator 33 Flow Control Valve 34 Switching Valve

Claims (1)

Claim: What is claimed is: 1. In a semiconductor acceleration sensor sensitivity measuring device for measuring sensor sensitivity in a wafer state, a means for blowing a predetermined flow rate of air to the wafer state inspection chip, the inspection chip and the probe. And a means for electrically processing a resistance value change of a strain gauge of the test chip to obtain a sensor output, and a means for processing the sensor output to obtain a sensor sensitivity and evaluating the sensor sensitivity. A sensitivity measuring device for a semiconductor acceleration sensor comprising: