JPH08124979A - Check method of semiconductor element - Google Patents

Abstract

PURPOSE: To provide a method of checking a semiconductor element, wherein the cause of failure is capable of being investigated immediately after the semiconductor element is judged defective. CONSTITUTION: This method of checking a semiconductor element is carried out through such a manner that a contact is made to bear successively against semiconductor elements formed on a wafer to measure the electrical properties of the semiconductor elements on the basis of their response to signals given to them (step 2), it is judged that the semiconductor element is defective or not (step 4), and a checking process is stopped as the contact is kept in contact with the semiconductor element when the semiconductor element is judged defective (step 7).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a semiconductor device, in which contacts are sequentially contacted with a plurality of semiconductor devices formed on a wafer to judge whether the electrical characteristics are good or bad.

[0002]

2. Description of the Related Art Conventionally, in order to measure the electrical characteristics of a plurality of semiconductor elements formed on a wafer, an electric signal corresponding to a predetermined test item is applied while a contactor is in contact with an electrode pad of the semiconductor element. It is given and the measurement based on the response is performed. As an inspection device that determines the quality by measuring the electrical characteristics of a semiconductor element, a measuring device (tester) for making a quality determination based on the generation of a signal according to a test item and its response, and a plurality of contacts are provided. It is composed of an automatic selection device (prober) which is brought into contact with a semiconductor element to be inspected and which transmits a signal from a measuring instrument and a response signal from the semiconductor element via the contactor.

Generally, in an inspection apparatus, a plurality of wafers (for example, 25 pieces in one lot) are set, and the wafers are placed one by one in an automatic sorting apparatus, and a plurality of semiconductor elements in the arranged wafers are sequentially arranged. Contact the contact. Then, a signal corresponding to several tens to several hundreds of test items is applied to each semiconductor element from a contactor, and a response signal thereof is sent to a measuring instrument to judge pass / fail based on electrical characteristics.

The measuring instrument obtains the response signal from the inspection object and based on a predetermined standard, the electrical characteristic rank (FBIN).
And sends the signal to the automatic sorting device. The automatic sorting device determines that the semiconductor device to be inspected is defective when it receives a preset FBIN, and applies ink to the semiconductor device to be inspected. In the subsequent process, the semiconductor element coated with the ink is excluded from the processing, so that defective products are excluded and only non-defective products are manufactured.

[0005]

However, such a semiconductor device inspection method has the following problems. That is, if the result is defective in the quality judgment,
In order to investigate the cause of the defect, it is necessary to find each semiconductor element that has been determined to be defective, which causes a problem that it takes a lot of time to clarify the cause. Also, after the inspection of all the wafers is completed, if the contactor is brought into contact with a semiconductor element judged to be defective again, the contact state cannot be reproducible. It will be difficult to find out whether the cause is due to another cause.

Further, even when the defect is determined to be due to other external factors (such as a change in the state of other related equipment or a change in the environment), the contactor is contacted again after a predetermined time has elapsed and the inspection is performed. If it is done, the result may be good, and it will be very difficult to investigate the cause at the stage when the defect is determined. Therefore, it is an object of the present invention to provide a method for inspecting a semiconductor element, which can immediately investigate the cause when a defect is determined.

[0007]

SUMMARY OF THE INVENTION The present invention is a method for inspecting a semiconductor device, which has been made to achieve the above object.
That is, the present invention sequentially contacts the plurality of semiconductor elements formed on the wafer with a contact, and determines the quality of the electrical characteristics based on the response to the signal given to the semiconductor element from the contact, A method of inspecting a semiconductor element, in which when the quality of electrical characteristics is determined to be defective, the inspection is stopped while maintaining the state of the contactor in contact with the semiconductor element being inspected at that stage. .

[0008]

According to the present invention, the contactor is brought into contact with the semiconductor element formed on the wafer, the quality of the electrical characteristics is judged, and when the contact is defective, the contactor contacting the semiconductor element at that stage is judged. Because the inspection is stopped while maintaining the condition,
When a defect is determined, the cause can be investigated immediately and in the same state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor element inspection method of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart for explaining an embodiment of a semiconductor element inspection method of the present invention, and FIG. 2 is a schematic diagram for explaining an inspection device. First, prior to describing the semiconductor device inspection method of the present invention, the inspection device will be described. 2 (a) is an overall view of the inspection device,
(B) is an enlarged view of the controller, and (c) shows an inspection state.

As shown in FIG. 2A, this inspection device 1
Is the generation of a signal according to the test item and the semiconductor element 11
A measuring device (tester) 2 for making a pass / fail judgment based on a response signal from (see FIG. 2C), and a plurality of contacts 12
An automatic selection device (prober) that abuts (see FIG. 2C) the semiconductor element 11 to be inspected and transmits the signal from the measuring instrument 2 and the response signal from the semiconductor element 11 via the contactor 12. 3, signal input / output between the measuring device 2 and the automatic sorting device 3 and the controller 4 for giving a signal for stopping the inspection to the automatic sorting device 3 when a predetermined determination is made and a defect judgment is made. It is composed of an interface cable 5 and an input / output cable 6.

As shown in FIG. 2B, the controller 4
Includes a numeric keypad 41 for inputting a predetermined numerical value, a display section 42, a set key 43 and a release key 43,
Further, a calculation unit (not shown) is provided inside. When performing the measurement, as shown in FIG. 2C, the contact 12 is brought into contact with the electrode pads (not shown) of the plurality of semiconductor elements 11 formed on the wafer 10 at a predetermined pressure, and A signal corresponding to the test item is sent from the measuring device 2 shown in a) to the contact 12 of the automatic sorting device 3 via the input / output cable 6.
Then, this signal is applied from the contact 12 to the semiconductor element 11, and the response signal is sent again from the contact 12 to the measuring instrument 2 via the input / output cable 6.

The measuring device 2 measures the electrical characteristics of the semiconductor element 11 to be inspected based on this response signal,
Calculate the rank according to a predetermined standard. This rank of electrical characteristics is called FBIN (abbreviation of Fail Bin), and the order of superiority and inferiority of characteristics is indicated by BIN numbers such as <1> to <15>. That is, for example, BIN number <
Settings such as 1> are good and <2> to <15> are bad (the smaller the number, the better the characteristic).

In general, the inspection apparatus 1 sequentially brings the contacts 12 into contact with a plurality of semiconductor elements 11 formed on the wafer 10 shown in FIG. We are testing 100 items. Further, the measuring device 2 calculates the FBIN based on the result of this test and sends the FBIN to the automatic selection device 3 and the controller 4 via the interface cable 5. The calculation unit (not shown) of the controller 4 uses the F obtained from the measuring device 2.
BIN and a preset FBIN are compared and calculated, and when they match, a signal for stopping the inspection is output to the automatic sorting apparatus 3.

Next, a method of inspecting the semiconductor element 11 using such an inspection apparatus 1 will be described in order with reference to FIG. 2 will be referred to for the reference numerals not shown in FIG. First, as the FBIN setting input shown in step S1, a predetermined BIN number is set and input using the ten-key 41 provided in the controller 4. The FBIN that is set and input here indicates the rank to be investigated for the cause of the defect.

Next, as shown in step S2, the characteristic measurement of the semiconductor element 11 based on the signal from the measuring device 2 is started. At the stage of the instruction to start the measurement, the automatic sorting apparatus 3 arranges the wafer 10 at a predetermined position and makes contact between one of the semiconductor elements 11 and the contact 12. The measuring instrument 2 sequentially sends signals corresponding to several tens to several hundreds of items to the automatic sorting device 3 via the input / output cable 6, and inputs the signals from the contact 12 to the semiconductor element 11 to be inspected. . Then, the response signal is transmitted again from the contact 12 to the measuring instrument 2 via the interface cable 5, and the measuring instrument 2 evaluates the electrical characteristics.

Next, the measuring device 2 which receives the response signal from the semiconductor element 11 as the FBIN output shown in step S3.
To output a BIN number according to the rank of electrical characteristics. A reference value corresponding to the rank of the electrical characteristic is set in the measuring instrument 2, and the measuring instrument 2 compares the electrical characteristic of the semiconductor element 11 to be inspected with the reference value to obtain the applicable rank. The corresponding FBIN is calculated and output to the automatic selection device 3 and the controller 4 via the interface cable 5.

Next, as a judgment as to whether the semiconductor element 11 to be inspected has a defect of a preset rank or not, the controller 4 judges whether or not the semiconductor element 11 to be inspected has a defect as shown in step S4. The rank used as a reference for the determination made by the controller 4 in this process is the FBIN set and input in step S1.

That is, the controller 4 controls the FBIN in the semiconductor element 11 to be inspected sent from the measuring instrument 2.
And FBIN that has been set and input in advance are compared. And
If the FBIN of the semiconductor element 11 to be inspected matches the FBIN set and input in advance, the determination in step S4 is Yes, and if they do not match, the determination in step S4 is No.

If the determination in step S4 is No,
That is, if the semiconductor elements 11 to be inspected are not defective in a preset rank, the process proceeds to the next step S5, and it is determined whether or not the inspection of all the semiconductor elements 11 is completed. If all semiconductor elements 11 have been inspected, the inspection process is terminated. If all semiconductor elements 11 have not been inspected, the process proceeds to step S6 and the next semiconductor element 11 is contacted with the contacts 12. To move. Then, the same measurement as above is repeated.

On the other hand, if the result of the determination in step S4 is Yes, that is, if the semiconductor element 11 to be inspected has a defect of a preset rank, the process proceeds to step S7. In step S7, the controller 4 sends a signal indicating an instruction to stop the inspection to the automatic sorting apparatus 3. The automatic selection device 3 immediately stops the inspection when it receives this signal from the controller 4. That is, the contact 1 is attached to the defective semiconductor element 11 of the preset rank.
The inspection is stopped in the state where 2 is still in contact.

Next, the cause of the defect is investigated in step S8. As described above, in step S7, the inspection is stopped in the state where the contact 12 remains in contact with the semiconductor element 11 for which the failure determination of the preset rank has been made. By investigating, it becomes possible to accurately investigate the cause when a defect appears.

For investigation of the cause of the defect, for example, the response signal waveform from the semiconductor element 11 in the defective measurement item is referred to, or the same contactor 12 as when the defect is judged by giving a signal to the semiconductor element 11 again. Is measured in the contact state to investigate whether the defect is in the circuit, the contact of the contact 12 is defective, or other cause. After conducting the above-mentioned investigation, the contact 12 may be re-applied to the semiconductor element 11 to measure the characteristics in different contact states.

By such an investigation, it is possible to investigate the cause while maintaining the state when the defect is determined, and it is possible to accurately determine the cause of the defect. If the cause of the defect is found to be due to a defect inside the circuit of the semiconductor element 11 by this defect cause investigation, the wafer 1
The content may be fed back to the manufacturing process at 0, and the same defect may be immediately dealt with so as not to occur. On the other hand, when it is found that the cause of the contact failure is the contact failure of the contactor 12, the contact pressure of the contactor 12 or the like is adjusted so that similar contact failure will not occur in the next inspection. Good.

After the defect cause investigation is completed, step S
As shown in 9, the stop is released. That is, the controller 4 sends a signal indicating the stop release to the automatic sorting device 3,
Normal inspection processing is resumed. Then, the process proceeds to step S5, and it is determined whether or not the inspection of all the semiconductor elements 11 is completed. If not completed, steps S6 to S are performed.
Proceed to 2 to start measurement of the next semiconductor element 11. When the inspection of all the semiconductor elements 11 has been completed, the inspection process is completed. With such a method of inspecting the semiconductor element 11, it is possible to immediately perform an appropriate cause investigation at the stage when a defect is determined.

[0025]

As described above, the method for inspecting a semiconductor device of the present invention has the following effects. That is, in the present invention, the quality of the electrical characteristics of the semiconductor element is determined, and when a defect is found, the inspection is stopped while maintaining the contact state of the contact at that stage, and therefore, when the defect is determined, With, it becomes possible to investigate the cause immediately.
Moreover, since the contact state of the contactor is maintained at the time of stop, it is possible to investigate the cause under the same conditions as when a defect judgment is made, and obtain an accurate investigation result of the defect cause. It will be possible. As a result, it is possible to significantly reduce the number of work steps required for investigating the cause of the defect in the semiconductor element.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating an inspection apparatus, in which (a) is an overall view, (b) is a controller, and (c) is an inspection state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection device 2 Measuring device 3 Automatic sorting device 4 Controller 5 Interface cable 6 Input / output cable 10 Wafer 11 Semiconductor element 12 Contact

Claims (1)

[Claims] 1. A contactor is sequentially brought into contact with a plurality of semiconductor elements formed on a wafer, and the quality of electrical characteristics is judged based on a response to a signal given from the contactor to the semiconductor element. When the pass / fail judgment in the electrical characteristics is defective, the inspection is stopped while maintaining the state of the contactor in contact with the semiconductor element being inspected at that stage. Device inspection method.