TWI435551B - Method and system for automatically testing the wireless chip - Google Patents

Description

Wireless chip automatic test method and system

The present invention relates to an automated test method, and more particularly to an automated test method and system for a wireless wafer.

Wireless communication devices (such as mobile phones) have become the electronic products that most people use today, and wireless chips (usually RF integrated circuits) are the main source of cost. In addition to R&D, design, and manufacturing, wireless wafer testing is often a major part of its production costs.

In general, testing of wireless wafers can be done using automated test equipment. Please refer to FIG. 1. FIG. 1 is a flow chart of automatic testing of the receiving performance of a conventional wireless chip. First, in step S11, the wireless wafer is tested to obtain the bit error rate of the wireless wafer. Next, in step S12, it is judged whether or not the bit error rate is lower than the standard value. If the bit error rate is lower than the standard value, step S13 is performed. In step S13, it is determined that the wireless chip is a good product, and the wireless wafer is placed in the good slot. Conversely, if the bit error rate is higher than the standard value, step S14 is performed. In step S14, it is determined that the wireless chip is a defective product, and the wireless wafer is placed in the defective product slot.

However, when the automatic test system performs the receiving energy test of the wireless chip, it is susceptible to environmental electromagnetic interference (EMI) and the test yield is lowered. Please refer to FIG. 2. FIG. 2 is a flow chart of a conventional automatic test method for a wireless chip. In Figure 2, the package tester uses a built-in antenna to construct an electromagnetic interference signal sensor, and determines whether the measured bit error rate is due to electromagnetic interference according to whether the signal strength of the electromagnetic interference noise exceeds the allowable range. There is a test error to further determine whether to retest the wireless chip.

First, in step S21, the wireless wafer is tested to obtain the bit error rate of the wireless wafer. Next, in step S22, it is judged whether or not the bit error rate is lower than the standard value. If the bit error rate is lower than the standard value, step S23 is performed. In step S23, it is determined that the wireless chip is a good product, and the wireless chip is placed in the good slot. If the bit error rate is not lower than the standard value, step S24 is performed. In step S24, the signal strength of the electromagnetic interference noise is sensed. Then, in step S25, it is judged whether or not the bit error rate of the test has a test error due to the influence of the electromagnetic interference noise. If the signal strength of the electromagnetic interference noise is within the allowable range, step S26 is performed. In step S26, it is determined that the wireless chip is a defective product, and the wireless wafer is placed in the defective product slot. If the signal strength of the electromagnetic interference noise exceeds the allowable range, return to step S21 to retest the wireless chip.

The difference between the test method of FIG. 2 and the test method of FIG. 1 is that when testing the wireless chip, if the signal strength of the electromagnetic interference noise is sensed, the bit error rate of the measurement is affected and the bit error rate is higher than the standard. A value indicates that the measured bit error rate may have a test error due to electromagnetic interference noise, and therefore, the wireless chip needs to be retested. In general, automated test equipment using the test method of Figure 2 can significantly improve the test yield loss originally caused by electromagnetic interference noise. However, the price paid is the time required for retesting, but since time is one of the cost factors, the test method of Figure 2 may have problems with increased test time and test cost.

Embodiments of the present invention provide an automatic test method for a wireless chip, which is implemented in an automatic test device to improve the test yield of the wireless chip. The automatic test method of the wireless chip includes the following steps: (1) testing the wireless chip to obtain the bit error rate of the wireless chip; (2) determining whether the bit error rate is lower than the standard value; (3) if the bit error If the rate is lower than the standard value, the wireless chip is judged to be a good product; (4) the signal intensity of the electromagnetic interference noise is sensed to determine whether the electromagnetic interference noise is sufficient to affect the measured bit error rate; (5) if the electromagnetic If the signal strength of the interference noise is still within the allowable range, and the bit error rate is higher than the standard value, the wireless chip is judged to be a faulty product; (5) if the signal strength of the electromagnetic interference noise exceeds the allowable range, and the bit If the element error rate is higher than the standard value, it means that the bit error rate of the measurement has a test error due to the influence of the electromagnetic interference noise, so the bit error rate is corrected according to the bit error rate and the signal strength of the electromagnetic interference noise; 6) judging whether the corrected bit error rate is lower than the standard value; (7) if the corrected bit error rate is lower than the standard value, determining that the wireless chip is a good product; (8) if the corrected bit error rate is Above the standard value, determine the wireless chip Fault goods.

The embodiment of the invention further provides an automatic test device for improving the test yield of the wireless chip. The automatic test equipment includes a test board, a control unit, an electromagnetic interference sensor, and a bit error rate corrector. The test board is used to place the wireless chip and test the wireless chip to obtain the bit error rate of the wireless chip. The control unit is configured to determine whether the bit error rate is lower than a standard value, and if the bit error rate is lower than the standard value, determine that the wireless chip is a good product. The electromagnetic interference sensor is used to sense the signal strength of the electromagnetic interference noise. The control unit determines that the signal strength of the electromagnetic interference noise is still within the allowable range and the bit error rate is higher than the standard value, and the control unit determines that the wireless chip is a faulty product. If the control unit determines that the signal strength of the electromagnetic interference noise exceeds the allowable range, the bit error rate corrector will correct the bit error rate according to the bit error rate and the signal strength of the electromagnetic interference noise. The control unit further determines whether the corrected bit error rate is lower than the standard value. If the corrected bit error rate is lower than the standard value, the control unit determines that the wireless chip is a good product. If the corrected bit error rate is higher than the standard value, the control unit determines that the wireless chip is a defective product.

In summary, the automatic test method and device for the wireless chip provided by the embodiments of the present invention can improve the test yield and achieve the effects of saving test time and test cost.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.

[Embodiment of Automatic Test Method for Wireless Wafer]

Please refer to FIG. 3. FIG. 3 is a flowchart of an automatic test method for a wireless chip according to an embodiment of the present invention. First, in step S31, the wireless wafer is tested to obtain the bit error rate of the wireless wafer. Then, in step S32, it is judged whether or not the bit error rate is lower than the standard value. Next, if the bit error rate is lower than the standard value, step S33 is performed. In step S33, it is determined that the wireless chip is a good product, and the wireless chip is placed in the good slot.

If the bit error rate is not lower than the standard value, step S34 is performed. In step S34, the signal strength of the electromagnetic interference noise is sensed. Thereafter, in step S35, it is determined whether the signal strength of the electromagnetic interference noise is sufficient to affect the measured bit error rate. If the signal strength of the electromagnetic interference noise is within the allowable range, step S36 is performed. In step S36, it is determined that the wireless chip is a defective product, and the wireless wafer is placed in the defective product slot. If the signal strength of the electromagnetic interference noise exceeds the allowable range, step S37 is performed. In step S37, the bit error rate is corrected according to the bit error rate and the signal strength of the electromagnetic interference noise.

Next, in step S38, it is judged whether or not the corrected bit error rate is lower than the standard value. If the corrected bit error rate is lower than the standard value, the process goes to step S33, and if the corrected bit error rate is not lower than the standard value, the process goes to step S36.

In this embodiment, the automatic test equipment (ATE) may be an automatic test equipment for testing a digital European Cordless Telecommunications (DECT) transceiver module, and the wireless chip may be a DECT transceiver. Module. However, the types of automatic test equipment and wireless wafers are for illustrative purposes only and are not intended to limit the invention.

Taking the automatic test equipment and the DECT transceiver module for testing the DECT transceiver module as an example, in step S31, the automatic test equipment performs a reception test on the DECT transceiver module to obtain the position of the DECT transceiver module. Meta error rate. The automatic test equipment can generate a plurality of known test signals that carry information of a plurality of predicted bits. The automatic test equipment transmits these test signals to the DECT transceiver module via electromagnetic waves via a free space path. After the DECT transceiver module receives and processes the test signals, the automatic test equipment captures a plurality of measurement bits generated by the DECT transceiver module through a low-parasitic socket. The automated test equipment then compares these predicted bits with the measurement bits to obtain a bit error rate.

Then, in step S32, the automatic test equipment determines whether the bit error rate is lower than the standard value. For example, the Bluetooth standard specifies a modulated RF signal with a power level of -70 dBm, and the output data of the receiver must have a bit error rate of no more than one thousandth (10 ^-3 ). If the bit error rate is lower than the standard value, the test passes, and in step S33, the automatic test device determines that the DECT transceiver module is a good product, and places the DECT transceiver module in the good slot.

When the bit error rate is not lower than the standard value, that is, the wireless chip fails the test, in step S34, the automatic test device senses the electromagnetic interference noise around the DECT transceiver module, and then in step S35, Determine if the signal strength of the electromagnetic interference noise is outside the allowable range. In more detail, in step S34, the automatic test equipment obtains the signal strength of the electromagnetic interference noise to further obtain the signal power of the electromagnetic interference noise, and in step S35, the automatic test equipment determines the signal of the electromagnetic interference noise. Whether the power is greater than a predetermined specification value (that is, whether the signal strength of the electromagnetic interference noise exceeds the allowable range) is used to determine whether the signal strength of the electromagnetic interference noise is sufficient to affect the test result.

Please refer to FIG. 4. FIG. 4 is a functional block diagram of an electromagnetic interference sensor according to an embodiment of the present invention. The electromagnetic interference sensor 4 is used to sense the signal power of the electromagnetic interference noise, and the electromagnetic interference sensor 4 may be part of the automatic test equipment or external to the automatic test equipment. In this embodiment, the electromagnetic interference sensor 4 is connected to a pin 44 of the automatic test equipment, that is, externally connected to the automatic test equipment. The electromagnetic interference sensor 4 includes a filter 45, an antenna 41, a low noise amplifier 42 and a power detector 43. The electromagnetic interference sensor 4 can transmit the signal power of the electromagnetic interference noise to the automatic test equipment through the pin 44. The antenna 41 is coupled to the filter 45, the filter 45 is coupled to the low noise amplifier 42, the low noise amplifier 42 is coupled to the power detector 43, and the power detector 43 is coupled to one of the automatic test equipment. Feet 44.

The antenna 41 is an antenna array for receiving electromagnetic interference noise and transmitting electromagnetic interference noise to the filter 45. The operating band of the antenna 41 includes a personal handy-phone system (PHS), a DECT, a Global System for Mobile Communications (GSM), and a digital cellular system (DCS). 880-960/1710-1910 MHz) and at least one of the Global Positioning System (GPS) and Wireless LAN (WLAN) 802.11b(g) use bands (1570/2450 MHz) One.

The filter 45 is used to filter out electromagnetic interference noise outside the operating band of the wireless chip, that is, the electromagnetic interference sensor 4 only senses electromagnetic interference noise of a common channel (co-channel). It should be noted that the filter 45 can also be removed, that is, the signal power of the electromagnetic interference noise of all frequencies can also be taken into consideration. The low noise amplifier 42 is configured to filter out the hot noise signal in the total noise signal received by the antenna 41, and amplify the total noise signal of the hot noise signal to generate electromagnetic interference noise. The power detector 43 can be a radio frequency power detector for receiving electromagnetic interference noise and generating electromagnetic interference noise power of electromagnetic interference noise.

The pins of the automatic test equipment are digital pins, analog pins or input and output pins. In summary, the form of the pins of the automatic test equipment is not intended to limit the invention. In addition, the pin of the above automatic test equipment is connected to a control unit in the automatic test equipment and a bit error rate controller, so that the control unit can determine whether the signal power of the electromagnetic interference noise is greater than a specification value, and This bit error rate corrector can obtain the signal power of the electromagnetic interference noise.

In addition, after the electromagnetic interference sensor detects the electromagnetic interference noise, in step S35, the automatic test equipment determines whether the signal strength of the electromagnetic interference noise exceeds the allowable range. For example, when PHS signal interference occurs, the power detector 43 outputs a DC pulse signal sequence, each pulse width is 577 microseconds (μs), and the pulse width of 577 microseconds is from the PHS standard operation time. Operational time slot. The above electromagnetic interference noise is described by taking a PHS signal as an example. However, the type of electromagnetic interference noise is not intended to limit the present invention.

Without loss of generality, the signal noise ratio can be expressed as follows. ,among them , S is the test signal, and n _t is the signal strength of the noise of the object to be tested. According to the reference, [V. Angelakis, S. Papadaki, V. Siris, and A. Traganitis, "Adjacent channel 425 interference in 802.11a: Modeling and test-bed validation," in Proc. IEEE 426 Radio Wireless Symp ., Jan. 22-24, 2008, pp. 591-594], n _I is the signal strength of the electromagnetic interference noise received by the receiver channel band. In addition, the total noise ratio of the signal can be expressed as follows. It is assumed that the signal strength n _t of the noise of the object to be tested is a random variable that is independent of each other and uncorrelated with the signal strength n _I of the electromagnetic interference noise.

In this embodiment, the manner of obtaining the total signal noise ratio based on the measured bit error rate of the original quantity is applied to the source-path-victim device by the Monte-Carlo method (Source-Path-Victim). The model is used to simulate the effect of electromagnetic interference on the deterioration of the bit error rate of the DECT transceiver module and to generate a corrected bit error rate accordingly. However, the method of correcting the bit error rate is not limited to this.

According to the reference, "Sachin Ganu and Shankar Sripadham, "Comparison of modulation techniques, GMSK and π/4'-DQPSK". SHANKAR@ee.vt.edu .", in Additive White Gaussian In Noise, AWGN), the theoretical bit error rate of Gaussian filter Minimum Shift Keying (GMSK) modulation can be estimated as Where α is a constant associated with the Bandwidth-Bitduration product (BT) (eg, BT = 0.25 then α = 0.68).

Meanwhile, according to the reference, "S. Chennakeshu and Gary J. Saulnier, "Differential detection of π/4-shifted-DQPSK for digital celluar radio," IEEE Trans. On Vehicular Tech. Vol. 42, No. 1, Feb. 1993 , pp.46-57.", the theoretical π/4-Differential Quadrature Phase Shift Keying (π/4-DQPSK) modulation bit error rate can be approximated by the following formula.

Where φ _i ( i =1 or 2) and Φ _i ( i =1 or 2) are the true phase angles of the received and two consecutive transmission symbols, respectively, and Δ Φ = Φ ₁ - Φ ₂ Under the condition of π/4, Φ _i =mπ/4, m=1～8.

The calculation method of obtaining the bit error rate according to the signal noise ratio can be calculated by the formula of the bit error rate of the above various modulation methods. In more detail, after obtaining the signal noise ratio, the signal noise ratio can be used instead of the total noise ratio of the signal, and the calculation formula of the bit error rate can be substituted, that is, the corrected bit error rate can be obtained.

In addition, it should be noted that the foregoing calculation method may also be replaced by a look-up table (LUT), that is, first storing a plurality of predicted bit error rates, predicting the signal power of the electromagnetic interference noise, and correspondingly The corrected predicted bit error rate is in the look-up table. After that, only the bit error rate and the signal power of the electromagnetic interference noise need to be known, and the nonlinear or linear interpolation operation can be used to obtain the corrected bit error. rate.

[Embodiment of Automatic Test Equipment for Wireless Wafer]

Please refer to FIG. 5. FIG. 5 is a functional block diagram of an automatic test device for a wireless chip according to an embodiment of the present invention. The automatic test equipment 50 of the wireless chip is used to improve the test yield of the wireless chip. The wireless wafer automatic test equipment 50 includes a test plate 51, a control unit 52, an electromagnetic interference sensor 53, and a bit error rate corrector 54.

The test board 51 is coupled to the control unit 52, and the test board 51 can be coupled to the wireless chip to be tested (for example, a DECT transceiver module) through a low parasitic socket (not shown) to pass the test to be tested. The board 51 is coupled to the control unit 52. The electromagnetic interference sensor 53 is coupled to the control unit 52 and the bit error rate corrector 54 , and the bit error rate corrector 54 is coupled to the control unit 52 .

The test board 51 is used to place the wireless chip and test the wireless chip to obtain a bit error rate of the wireless chip. The electromagnetic interference sensor 53 is used to sense electromagnetic interference noise. The electromagnetic interference sensor 53 is controlled by the control unit 52 and is configured to transmit the sensed electromagnetic interference noise to the bit error rate corrector 54.

The control unit 52 is configured to determine whether the bit error rate is lower than a standard value. If the bit error rate is lower than the standard value, it is judged that the wireless chip is a good product. In addition, the control unit 52 further determines whether the signal strength of the electromagnetic interference noise is within an allowable range. If the bit error rate is higher than the standard value and the signal strength of the electromagnetic interference noise is within the allowable range, the control unit 52 determines that the wireless chip is a defective product. In addition, the control unit 52 further determines whether the corrected bit error rate is lower than the standard value. If the corrected bit error rate is lower than the standard value, the control unit 52 determines that the wireless chip is a good product. If the corrected bit error rate is higher than the standard value, the control unit 52 determines that the wireless chip is a defective product.

The bit error rate corrector 54 transmits the corrected element error rate to the control unit 52. If the bit error rate is higher than the standard value and the signal strength of the electromagnetic interference noise exceeds the allowable range, the bit error rate corrector 54 corrects the bit error rate according to the bit error rate and the signal strength of the electromagnetic interference noise.

When testing the performance of the wireless chip receiving signal to be tested, the control unit 52 controls the test board 51 to transmit a plurality of test signals (information with a plurality of predicted bits), and the plurality of test signals are transmitted through the free space channel. To the wireless chip to be tested, and the control unit 52 draws a plurality of measurement bits generated by the wireless wafer receiving and processing the test signal to be tested through the low parasitic socket (not shown) of the test board 51. Next, control unit 52 compares the pre-known bit with the measurement bit to obtain a bit error rate.

[Possible efficacy of the embodiment]

According to the embodiment of the invention, the above-mentioned automatic test method and device for the wireless chip can improve the test yield and achieve the effect of saving test time and test cost.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

S11～S14, S21～S26, S31～S38. . . Step flow

4, 53. . . Electromagnetic interference sensor

41. . . antenna

42. . . Low noise amplifier

43. . . Power detector

44. . . One pin of the automatic test equipment

45. . . filter

50. . . Wireless chip automatic test equipment

51. . . Test board

52. . . control unit

54. . . Bit error rate corrector

FIG. 1 is an automatic test flow chart of the receiving performance of a conventional wireless chip.

2 is a flow chart of a conventional wireless chip automatic test method.

3 is a flow chart of an automatic test method for a wireless chip according to an embodiment of the present invention.

4 is a functional block diagram of an electromagnetic interference sensor according to an embodiment of the present invention.

FIG. 5 is a functional block diagram of an automatic test device for a wireless chip according to an embodiment of the present invention.

S31～S38. . . Step flow

Claims (8)

An automatic test method for a wireless chip is implemented in an automatic test device for improving a test yield of a wireless chip. The automatic test method for the wireless chip includes: testing the wireless chip to obtain the wireless chip. a bit error rate; determining whether the bit error rate is lower than a standard value; if the bit error rate is lower than the standard value, determining that the wireless chip is a good product; sensing the signal strength of an electromagnetic interference noise Determining whether the signal strength of the electromagnetic interference noise exceeds a allowable range to determine whether the signal strength of the electromagnetic interference noise is sufficient to affect the bit error rate; if the electromagnetic interference noise intensity is within the allowable range, and the If the bit error rate is higher than the standard value, the wireless chip is determined to be a faulty product; if the electromagnetic interference noise intensity exceeds the allowable range, and the bit error rate is higher than the standard value, the bit error is determined according to the bit error Rate and the signal strength of the electromagnetic interference noise correct the bit error rate, wherein the bit error is corrected according to the bit error rate and the signal strength of the electromagnetic interference noise The step of rate includes: obtaining a signal-to-to-to-to-to-noise ratio (STNR) according to the bit error rate measured after the wireless chip is tested; according to the signal strength of the electromagnetic interference noise Acquiring the signal power of the electromagnetic interference noise; obtaining a signal-to-interference ratio (SIR) according to the predicted test signal power and the signal power of the electromagnetic interference noise; and according to the signal interference ratio and the signal The total noise ratio is obtained by a Signal-to-Noise Ratio (SNR); and the noise ratio is obtained according to the signal-to-noise ratio The corrected bit error rate; determining whether the corrected bit error rate is lower than the standard value; if the corrected bit error rate is lower than the standard value, determining that the wireless chip is the good product; If the corrected bit error rate is higher than the standard value, it is determined that the wireless chip is the faulty product. The automatic test method for a wireless chip according to claim 1, wherein the signal noise ratio is calculated as follows: The method for automatically testing a wireless chip according to claim 1, wherein the step of obtaining the bit error rate of the wireless chip comprises: transmitting a predetermined plurality of test signals to the wireless chip, wherein the test signals are used. The plurality of pre-known bits are generated by the wireless chip receiving and processing; obtaining a plurality of measurement bits generated by the wireless chip after receiving and processing the test signals; and comparing the predicted bits with the quantities The bit is measured to obtain the bit error rate. The automatic test method for a wireless chip according to claim 1, wherein the automatic test device has a test board for placing the wireless chip, the automatic test device having an electromagnetic interference sensor, the electromagnetic interference feeling The detector is configured to sense the signal strength of the electromagnetic interference noise, and has an antenna array disposed near a position for placing the wireless chip, wherein the antenna array has at least one operating frequency band. Automatic testing of wireless wafers as described in claim 4 The method, wherein the at least one operating band comprises at least a Global System for Mobile Communications (GSM), a Digital Cell System (DCS), a Global Positioning System (GPS), a Wireless Local Area Network (WLAN), and a Personal Handyphone System (PHS) One of a plurality of communication bands used. The automatic test method for a wireless chip according to claim 1, wherein the wireless chip is a radio frequency integrated circuit chip. An automatic test device for improving test yield of a wireless chip, the automatic test device comprising: a test board for placing the wireless chip, and testing the wireless chip to obtain one of the wireless chips a bit error rate; a control unit for determining whether the bit error rate is lower than a standard value, and if the bit error rate is lower than the standard value, determining that the wireless chip is a good product; an electromagnetic interference sensing And a one-bit error rate corrector, if the bit error rate is higher than the standard value, and the control unit determines that the signal strength of the electromagnetic interference noise exceeds Having a range, the bit error rate is corrected according to the bit error rate and the signal strength of the electromagnetic interference noise; wherein the control unit further determines whether the signal strength of the electromagnetic interference noise is within the allowable range, If the bit error rate is higher than the standard value, and the control unit determines that the signal strength of the electromagnetic interference noise is within the allowable range, the control unit determines that the wireless chip is a faulty product. The control unit further determines whether the corrected bit error rate is lower than the standard value. If the corrected bit error rate is lower than the standard value, the control unit determines that the wireless chip is the good product; The bit error rate is higher than the standard value, and the control unit determines that the wireless chip is the faulty product; wherein the error rate corrector obtains a signal according to the bit error rate measured after the wireless chip is tested. The total noise ratio; then, the electromagnetic interference sensor calculates the signal power of the electromagnetic interference noise according to the signal intensity of the electromagnetic interference noise, and the bit error rate corrector according to the predicted test signal power and the electromagnetic The signal power of the interference noise obtains a signal interference ratio; then, the error rate corrector obtains a signal noise ratio according to the signal interference ratio and the total noise ratio of the signal, and obtains the corrected noise according to the signal noise ratio The bit error rate; wherein the signal noise ratio is calculated as follows: The automatic test equipment of claim 7, wherein the electromagnetic interference sensor comprises: an antenna array disposed near a position for placing the wireless chip, having at least one operating frequency band; and a low noise An amplifier for filtering a thermal noise signal in a total noise signal received by the antenna array, and amplifying the total noise signal of the thermal noise signal to generate the electromagnetic interference noise; A power detector receives the electromagnetic interference noise to generate an electromagnetic interference noise power of the electromagnetic interference noise.