TWI490486B - System of built-in self-test for sensing element and method thereof - Google Patents

Description

Self-test system for sensing elements and method thereof

The present invention provides a self-test system for sensing components, and more particularly to a self-test system for wafer level sensing components that can effectively reduce test costs and improve detection efficiency.

As the application of MEMS components is becoming more and more extensive, and the development of semiconductor technology is becoming more and more mature, the price of MEMS components is decreasing year by year, and the cost of component testing is difficult to reduce due to the high-priced test machine required. Effectively reduce overall costs.

In particular, at present, in the wafer level component test, an external measuring instrument must be used in the test process, and the micro-capacitance measurement of the micro-electromechanical system (MEMS) wafer-level structure can be performed by the wiring of the external wires. However, because it needs to be used with external measuring instruments, in the mass production stage, after considering the instrument cost and the test time cost, the output profit will not be maximized and it is difficult to enhance the market competitiveness.

In view of the above problems, it is urgent to propose a self-test system and method for wafer level sensing elements with high efficiency and high efficiency.

It is an object of the present invention to provide a self-test system for sensing components.

According to an embodiment of the invention, a self-test system for a sensing component includes a sensing component and a test module. The sensing component includes a fixed unit and a movable unit, wherein a sensing capacitor is formed between the fixed unit and the movable unit. The test module is electrically connected to the sensing component, and the test module includes a test circuit for measuring the sensing capacitor. The sensing component is configured to receive an input signal, so that the sensing capacitor generates a capacitance value change, and the test circuit outputs a test signal according to the capacitance value change amount.

Another object of the present invention is to provide a method for sensing a self-test system of components.

According to another embodiment of the present invention, a method for sensing a self-test system of a component includes the steps of: first, providing an input signal to the sensing component; and second, generating a capacitance value change of the sensing capacitor according to the input signal. The amount; in addition, according to the amount of change in the capacitance value, a test signal is output.

100‧‧‧Self Test System

110‧‧‧Sensor components

111‧‧‧Fixed unit

112a-112b‧‧‧Fixed Arm

113‧‧‧Signal input

114‧‧‧Signal output

115‧‧‧ movable unit

116‧‧‧Quality

117‧‧‧ moving arm

118a-118b‧‧‧Spring parts

119‧‧‧ signal input

120‧‧‧Test module

122‧‧‧Test circuit

124‧‧‧Transistor Amplifier

125‧‧‧ Mixer

126‧‧‧ filter

130‧‧‧Induction Capacitance

132‧‧‧First induction capacitor

134‧‧‧second induction capacitor

136‧‧‧Parasitic capacitance

140‧‧‧Input signal

142‧‧‧ incentive signal

144‧‧‧Transformation signal

150‧‧‧Test signal

300‧‧‧Self Test System

310‧‧‧Sensor components

320‧‧‧Test module

322‧‧‧Test circuit

360‧‧‧ Probe Card

370‧‧‧Test circuit board

400‧‧‧ method

410‧‧‧Steps

420‧‧ steps

430‧‧ steps

[Fig. AA] is a schematic diagram showing a self-test system for sensing elements in accordance with an embodiment of the present invention.

[Fig. B] shows an equivalent circuit diagram of the self-test system in Fig. A.

[Fig. 2A] is a diagram showing an output signal of a transimpedance amplifier in a test circuit according to an embodiment of the present invention.

[Fig. 2B] is a diagram showing an output signal of a mixer in a test circuit according to an embodiment of the present invention.

[Second C] is a diagram showing an output signal of a filter in a test circuit according to an embodiment of the present invention.

[Third A] is a functional block diagram of a self-test system according to another embodiment of the present invention.

[Third B] is a functional block diagram of a self-test system according to another embodiment of the present invention.

[Fourth Diagram] is a flow chart showing a method for a self-test system for sensing components according to another embodiment of the present invention.

In order to make the description of the present invention more complete and complete, reference is made to the accompanying drawings and the accompanying drawings. On the other hand, well-known elements and steps are not described in the embodiments to avoid unnecessarily limiting the invention.

Please refer to FIG. 1A, which is a schematic diagram of a self-test system 100 for sensing components in accordance with an embodiment of the present invention. The self-test system 100 includes a sensing component 110 and a test module 120. The sensing component 110 includes a fixed unit 111 and a movable unit 115. The sensing capacitor 130 is formed between the fixed unit 111 and the movable unit 115. The test module 120 is electrically connected to the sensing component 110, and the test module 120 includes a test circuit 122 for measuring the sensing capacitor 130. Specifically, the sensing component 110 is configured to receive an input signal 140, such that the sensing capacitor 130 generates a capacitance value change, and the test circuit 122 outputs a test signal 150 according to the capacitance value change amount.

As shown in FIG. A, the fixing unit 111 includes two fixing arms 112a-112b, and the movable unit 115 includes a mass 116 and a moving arm 117, wherein the moving arm 117 is disposed on the mass 116, and the moving arm 117 Located between the fixed arms 112a-112b to form the sensing capacitor 130. Further, between the two fixed arms 112a-112b and the moving arm 117, a first sensing capacitor (C1) 132 and a second sensing capacitor (C2) 134 are formed, and the fixed arms 112a-112b form a Parasitic capacitance (C3) 136.

In addition, in an embodiment, the fixed unit 111 and the movable unit 115 respectively include a signal input end 113 and a signal input end 119 for receiving the input signal 140. More specifically, the signal input terminal 113 is disposed on the fixed arm 112a and is configured to receive an excitation signal 142. The signal input terminal 119 is disposed at one end of the movable unit 115 for receiving a modulation signal 144. However, when the modulation signal 144 is input to the movable unit 115 via the signal input terminal 119, the movable unit 115 is caused to generate an electrostatic force correspondingly, and the driving mass 116 is displaced, thereby changing the moving arm 117 and the two fixed arms 112a-112b, respectively. the distance between. Therefore, the capacitance values of the first sensing capacitor 132 and the second sensing capacitor 134 will also change corresponding to the capacitance value as the distance between the moving arm 117 and the two fixed arms 112a-112b changes.

In an embodiment, the fixed unit 111 includes a signal output end 114. As shown in the figure, the signal output end 114 is located at one end of the fixed arm 112b. Therefore, the test module 120 can pass through the electrical contact signal output end 114 to detect the change in the capacitance value of the sensing capacitor 130, and the test module is used. The test circuit 122 inside 120 performs signal processing to output a test signal to determine whether the sensing element 110 is good or not.

Further, in an embodiment, as shown in FIG. A, the movable unit 116 includes spring members 118a-118b. The spring members 118a-118b are respectively disposed at two ends of the mass block 116 for synchronously providing an elastic force when the mass block 116 is displaced by the electrostatic force, thereby allowing the mass block 116 to be subsequently reset to the initial position.

Please refer to FIG. B, which is an equivalent circuit diagram of the self-test system 100 in FIG. As shown in FIG. B, the test circuit 122 includes a transimpedance amplifier 124, a mixer 125, and a filter 126. In this embodiment, the frequency of the modulation signal 144 input from the signal input terminal 119 to the sensing capacitor 130 is about 1 MHz, which is used to generate an electrostatic force to change the capacitance values of the first sensing capacitor 132 and the second sensing capacitor 134. . In addition, the excitation signal 142 is input from the signal input terminal 113 to the sensing capacitor 130. The frequency is about 2KHz Hertz, where the frequency of the excitation signal 142 is viewed at the resonant frequency of the overall equivalent circuit. However, when the excitation signal 142 and the modulation signal 144 are input to the sensing capacitor 130, the induced current signals Ip and Im are generated correspondingly, and outputted from the signal output terminal 114, as shown in the figure, wherein the induced current signal Ip flows through The current signal of the parasitic capacitance 136, and the frequency of the induced current signal Ip is 2KHz Hz; relatively speaking, the induced current signal Im is a current signal flowing through the first sensing capacitor 132 and the second sensing capacitor 134, and the induced current signal Im Mixed current signal with frequency 2KHz Hertz and frequency 1MHz Hertz.

When the test module 120 is electrically connected to the signal output terminal 114, the transimpedance amplifier 124 draws the current signals Ip and Im, and converts them into voltage signals Vp and Vm, respectively, and sequentially transmits them to the mixer 125 and the filter. 126, for signal processing of signal modulation and signal filtering, and then reading and generating test signal 150. In one embodiment, filter 126 is a low pass filter for filtering high frequency signals while preserving the desired primary low frequency signals.

Please refer to the second to second C diagrams synchronously, which respectively correspond to the output signal diagrams of the transimpedance amplifier, the mixer and the filter in the test circuit. More specifically, as shown in FIG. 2A, the transimpedance amplifier 124 converts the extracted current signals Ip and Im to the output voltage signals Vp and Vm, respectively, wherein the frequency of the voltage signal Vp is 2KHz Hertz, and the voltage signal is The frequency of Vm is 1 MHz Hz. Next, as shown in FIG. B, when the mixer 125 receives the voltage signals Vp and Vm, the signal is modulated by using a 1 MHz Hz signal, and the voltage signal Vm is down-converted to a voltage signal of 2 kHz Hertz. The signal Vp is up-converted to 1 MHz, and the modulated voltage signals Vp and Vm are output. Furthermore, as shown in FIG. 2C, the filter 126 passes the main required voltage signal Vm and attenuates the intensity of the voltage signal Vp to filter the voltage signal Vp while retaining the main voltage signal Vm.

In this way, the test circuit 122 can determine whether the sensing component 110 is complete according to the voltage signal Vm output by the filter 126 to output the test signal 150.

In addition, in a preferred embodiment, as shown in FIG. 3A, the test module 320 of the self-test system 300 can be built in a probe card 360 to detect through the test circuit 322. The voltage signal Vm at the output of the test signal. Furthermore, as shown in FIG. B, the test module 320 of the self-test system and its test circuit 322 can also be used as a test board 370 built into a conventional tester. Reduce the cost of external precision measuring instruments and test time costs, and achieve the purpose of small capacitance measurement. Please refer to the fourth figure, which illustrates a flow chart of a method 400 for sensing a component self-test system in accordance with another embodiment of the present invention. As shown, method 400 includes step 410, step 420, and step 430. However, with regard to the self-test system implementing the method 400, since the above embodiments have been specifically disclosed, the description thereof will not be repeated.

As shown in the fourth figure, in step 410, an input signal can be provided to the sensing element. In step 420, a capacitance value change of one of the sensing capacitors may be generated according to the input signal. In step 430, a test signal can be output according to the amount of change in the capacitance value.

More specifically, in step 410, an input signal is provided to the movable unit and the fixed unit in the sensing element. In one embodiment, the input signal includes a modulation signal and an excitation signal, which are respectively input to the movable unit and the fixed unit.

However, in step 420, when the movable unit receives the modulation signal, an electric static force is generated and displaced to change the distance between the movable unit and the fixed unit. In this way, the amount of change in the capacitance value corresponding to the induced capacitance formed between the movable unit and the fixed unit can be caused.

In step 430, the method 400 can pass the test module to sense the amount of change in the capacitance of the sensing capacitor to output a test signal. In one embodiment, the test module includes a transimpedance amplifier, mixed The frequency converter and the filter perform signal processing detection through an output signal that is obtained by sensing a change in the capacitance value of the sensing capacitance from the sensing element, thereby determining whether the reading is good and complete, and outputting the test signal.

Therefore, by performing the self-test system for sensing elements and the method thereof according to the above embodiments of the present invention, it is possible to perform detection only when an input signal is generated by an arbitrary waveform generator at the wafer level test. And the design of the required test circuit is simple, completely replaces the external measuring instrument, and can greatly reduce the overall testing cost. In addition, by integrating the test circuit on the test module, the test time can be shortened to increase the test efficiency.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧Self Test System

110‧‧‧Sensor components

111‧‧‧Fixed unit

112a-112b‧‧‧Fixed Arm

113‧‧‧Signal input

114‧‧‧Signal output

115‧‧‧ movable unit

116‧‧‧Quality

117‧‧‧ moving arm

118a-118b‧‧‧Spring parts

119‧‧‧ signal input

120‧‧‧Test module

122‧‧‧Test circuit

130‧‧‧Induction Capacitance

132‧‧‧First induction capacitor

134‧‧‧second induction capacitor

136‧‧‧Parasitic capacitance

140‧‧‧Input signal

142‧‧‧ incentive signal

144‧‧‧Transformation signal

150‧‧‧Test signal

Claims (13)

A self-test system for a wafer level sensing component, comprising: a sensing component comprising a fixed unit and a movable unit, wherein the fixed unit forms a sensing capacitor with the movable unit; and a test module The test module includes a test circuit for measuring the sensing capacitor. The sensing component is configured to receive an input signal to generate a capacitance value. The amount of change, and the test circuit outputs a test signal according to the amount of change in the capacitance value. The self-test system for wafer level sensing elements of claim 1, wherein the fixing unit comprises at least two fixed arms. The self-test system for a wafer level sensing component according to claim 2, wherein the movable unit comprises a mass and a moving arm, wherein the moving arm is disposed on the mass, and the moving arm Located between the fixed arms. A self-test system for a wafer level sensing element according to claim 1, wherein the movable unit comprises a spring member. The self-test system for a wafer level sensing component according to claim 1, wherein the fixed unit and the movable unit respectively comprise a signal input end. The self-test system for a wafer level sensing component according to claim 5, wherein the fixing unit further comprises a signal output end. The self-test system for a wafer level sensing component according to claim 1, wherein the test circuit comprises a transimpedance amplifier, a mixer and a filter. The self-test system for a wafer level sensing component according to claim 1, wherein the test circuit is built in a probe card or a test circuit board of a test machine. A self-test method for a wafer level sensing component, wherein the sensing component comprises a movable unit and a fixed unit, and the movable unit forms a sensing capacitance with the fixed unit, the method comprising: providing an input signal Up to the sensing component; generating a capacitance value change of the one of the sensing capacitors according to the input signal; and outputting a test signal according to the amount of change of the capacitance value. The self-test method for a wafer level sensing component according to claim 9, wherein the input signal comprises an excitation signal and a modulation signal. The self-test method for a wafer level sensing component according to claim 10, wherein the step of providing the input signal comprises: inputting the modulation signal and the excitation signal to the movable unit and the fixing separately unit. The self-test method for a wafer level sensing component according to claim 9 , wherein the step of outputting the test signal comprises: detecting a change in the capacitance value of the sensing capacitor by using a sensing circuit, Whether the interpretation is good and complete. The self-test method for a wafer level sensing component according to claim 12, wherein the sensing circuit comprises a transducing amplifier, a mixer and a filter.