Common test methods for IC detection of semiconductor chips

Date：2021-10-21 18:15:03Views：1435

Semiconductor chip IC is very sensitive, so when testing, pay attention not to cause short circuit between pins. Short circuit at any moment can be captured, resulting in burn out of integrated circuit. All the components have formed a whole in structure, which makes the electronic components take a big step towards miniaturization, low power consumption, intelligence and high reliability. The work to be done before testing is to fully understand the working principle of integrated circuits. Be familiar with its internal circuit, main parameters, functions of each outgoing line and its normal voltage.

Common detection methods for IC detection of semiconductor chips

The common detection methods of integrated circuits include on-line measurement method, off-line measurement method and substitution method.

1. Off line measurement when the integrated circuit is not welded into the circuit, the DC resistance between its pins is measured and compared with the DC resistance between the pins of the known normal integrated circuit of the same model to determine whether it is normal.

2. Online measurement online measurement method uses voltage measurement method, resistance measurement method and current measurement method to judge whether the integrated circuit is damaged by measuring whether the voltage value, resistance value and current value of each pin of the integrated circuit are normal.

3. Substitution method substitution method is to replace the tested integrated circuit with a known intact integrated circuit of the same model and specification, which can judge whether the integrated circuit is damaged.

Detection of common integrated circuits

1. Detection of microprocessor integrated circuit the key test pins of microprocessor integrated circuit are VDD power supply terminal, reset terminal, Xin crystal oscillator signal input terminal, xout crystal oscillator signal output terminal and other line input and output terminals. Measure the resistance and voltage of these key pins to the ground to see if they are the same as the normal values (which can be found out from the product circuit diagram or relevant maintenance data). The reset voltage of different types of microprocessors is also different. Some are low-level reset, that is, it is low-level at the moment of startup and remains high-level after reset; Some are high level reset, that is, it is high level at the moment of switching, and maintain low level after reset.

2. Detection of switching power supply integrated circuit the key pin voltage of switching power supply integrated circuit is power supply terminal (VCC), excitation pulse output terminal, voltage detection input terminal and current detection input terminal. Measure the voltage and resistance of each pin to the ground. If there is a large difference from the normal value, it can be determined that the integrated circuit has been damaged when its peripheral components are normal. The thick film integrated circuit with built-in high-power switch tube can also judge whether the switch tube is normal by measuring the forward and reverse resistance values between poles C, B and e of the switch tube.

3. Detection of audio power amplifier integrated circuit when checking the audio power amplifier integrated circuit, first detect the voltage and resistance to the ground at its power terminal (positive power terminal and negative power terminal), audio input terminal, audio output terminal and feedback terminal. If the measured data value of each pin is quite different from the normal value, and its peripheral components are normal, it is the internal damage of the integrated circuit. When the power supply voltage of audio power amplifier IC causing silent fault is normal, it can be checked by signal interference method. When measuring, the multimeter should be placed in R × In gear 1, ground the red probe and touch the audio input with the black probe. There should be a strong "click" sound in the speaker under normal conditions.

4. For the detection of operational amplifier integrated circuit, use the DC voltage gear of multimeter to measure the voltage value between the output end of operational amplifier and the negative power supply end (the voltage value is high in static state). Touch the two input terminals of the operational amplifier successively with hand-held metal tweezers (add interference signal). If the multimeter needle swings greatly, it indicates that the operational amplifier is intact; If the multimeter needle does not move, the operational amplifier is damaged.

5. Detection of time-based integrated circuit time-based integrated circuit contains digital circuit and analog circuit. It is difficult to directly measure its quality with a multimeter. The test circuit consists of resistance capacitance element, led, 6V DC power supply, power switch s and 8-pin IC socket. After inserting the time base integrated circuit (such as NE555) into the IC socket, press the power switch S. if the measured time base integrated circuit is normal, the LED will flash; If the LED is not on or always on, it indicates that the performance of the time-based integrated circuit under test is poor.

As for IC testing equipment, because the production of IC is usually very large, it must be incompetent to test manually such as multimeter and oscilloscope. At present, the test equipment is usually fully automatic and multi-functional combined measuring device and controlled by program. Basically, these test equipment can be regarded as a special industrial robot for measurement.

In conclusion, the testing of semiconductor IC is a very complex system engineering, and it is impossible to simply describe how to judge whether it is qualified or unqualified. Generally speaking, the test is carried out according to the design requirements, and those that do not meet the design requirements are unqualified. The design requirements vary according to different products. Some ICs need to detect a large number of parameters, while others only need to detect few parameters. In fact, a specific IC does not have to go through all the tests mentioned above. For an IC that has gone through multiple test processes, there are many changes in which process and which parameters to test. This is a complex system engineering.