Integrated circuit inspection (wafer inspection), chip test (chip inspection) and package test (package inspection).
Wafer testing is a test after the wafer is produced from the wafer factory and before cutting and thinning. Its equipment is usually developed, manufactured or customized by test manufacturers. Generally, the wafer is placed on the test platform and the pre-determined detection points in the chip are detected with probes. The probe can detect various electrical parameters through DC current and AC signal.
For optical integrated circuits, it is also necessary to test their electrical properties under given lighting conditions.
Wefer test main equipment: probe platform.
Weaver test AIDS: clean room and complete sets of equipment.
Wefer test is the most efficient test, because there are often hundreds to thousands or even tens of thousands of chips on a wafer, and all these chips can be tested at one time on the test platform.
Chip testing is a test after the wafer is cut and thinned into individual chips. Its equipment is usually developed, manufactured or customized by test manufacturers. Generally, the wafer is placed on the test platform and the pre-determined detection points in the chip are detected with probes. The probe can detect various electrical parameters through DC current and AC signal. The main difference between chip test equipment and wafer test equipment is that the fixture is different because of the different shape and size of the tested object.
For optical integrated circuits, it is also necessary to test their electrical properties under given lighting conditions.
Main equipment for chip testing: probe platform (including fixtures for holding chips of different specifications)
Auxiliary equipment for chip testing: clean room and complete sets of equipment.
The range that chip testing can detect is similar to that of wafer testing. Because it has gone through the process of cutting and thinning, it can also pick out the defective products damaged in the process of cutting and thinning. But the efficiency of chip testing is much lower than that of wafer testing.
Packaging test is the test after the chip is packaged into a finished product. Because the chip has been packaged and no clean room environment is needed, the test requirements are greatly reduced.
Generally, equipment for package testing is also developed or customized by various manufacturers, and usually includes sensors for testing various electronic or optical parameters. But usually, the probe is not used to probe into the chip (most chips can't probe into it after packaging), but to test directly from the pin connection.
Because the package test can't use probes to test the inside of the chip, its test range is limited, and many indicators can't be tested at this stage. But the packaging test is the final product test, so it is the final qualified product that passes the test.
IC testing is a rather complicated system engineering, which can't simply tell you how to judge whether it is qualified or not.
Generally speaking, it is tested according to the design requirements, and those that do not meet the design requirements are unqualified. However, the design requirements vary from product to product. Some ics need to detect a large number of parameters, while others only need to detect a small number of parameters.
In fact, a specific ic doesn't have to go through all the tests mentioned above. An IC that has been tested for many times has many changes in which process and which parameters to test. This is a complicated system engineering.
For example, for chips with large chip area, high yield and low packaging cost, wafer testing is usually not needed, while for chips with small chip area, low yield and high packaging cost, it is best to carry out a lot of tests in wafer testing to find defective products as soon as possible, so as to avoid them mixing into the packaging process and unnecessarily increasing the packaging cost.
Integrated circuit test equipment, because the output of integrated circuits is usually huge, must be tested manually with multimeter and oscilloscope. At present, the detection equipment is usually a fully automatic multifunctional combined measuring device, and it is controlled by the program. You can basically think that these inspection equipments are industrial robots specially used for measurement.
Integrated circuit testing is a very important link in the process of integrated circuit production. In most integrated circuits at present, the cost of testing often accounts for 1/4 to half of the total cost.