JPH0441495B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a semiconductor wafer measuring method.

(Prior Art and Problems to be Solved by the Invention) When applying a conventional semiconductor wafer measuring device, an operator first measures one chip among hundreds of identical chips on a wafer. Touch the probe card needle to the pad inside the chip and confirm that it is in the correct position using a microscope, monitor TV, etc. After that, we rely only on the mechanical accuracy of the semiconductor wafer measuring device (including the accuracy of the automatic confirmation device) and the repeatability of the chip, and on the assumption that the probe card needle is in contact with the pad, we connect it to the probe card needle. A tester is used to judge the quality of the chip.

When a chip is determined to be defective through the above determination process, it is possible to determine whether the chip is truly defective or whether the probe card needle was determined to be defective because it was not in contact with the electrode pad surface of the semiconductor wafer. It is not possible to distinguish either. Therefore, if the actual wafer prober continues to fail during measurement, the test is repeated by returning to the previous chip before the number of defective chips continued, and touching the probe card needle row to the chip at the returned position again. . If the measurement result is as bad as the previous result, it is determined that the chip is defective. However, the poor contact between the probe card needle and the surface of the electrode pad of the semiconductor chip has not yet been resolved. Even though this is an automatic semiconductor wafer measuring device, the actual situation is that testing is performed with the intervention of many more people.

In addition, in testing semiconductor wafer chips,
Particularly in today's highly integrated chips, there are chips that are judged to be non-defective because the probe card needle comes into contact with the inside of the pad under the narrowest possible conditions. These chips are also made into integrated circuit (IC) products by cutting them individually from the wafer and packaging them separately.
As mentioned above, a chip that becomes a non-defective product under the marginal conditions does not have the margin to be a non-defective product in the integrated circuit product it is used in, and it may fail earlier than other integrated circuit products manufactured using other non-defective products, resulting in serious damage. This leads to a decrease in reliability.

The present invention has been made in response to the above-mentioned problems, and provides a method for measuring a semiconductor wafer in which the state of contact of a probe needle with an object to be measured during measurement can be determined after measurement.

[Structure of the invention]

(Means for Solving the Problems) This invention provides a method for electrically measuring each chip in a semiconductor wafer to be measured by successively contacting each chip with a probe needle, in which each chip is contacted by the probe needle after electrical measurement. The method includes a step of detecting a needle mark, a step of inspecting the contact status of the probe needle at the time of the above measurement from the needle mark detected by this step, and a step of confirming the measurement result of the tip from the test result of this step. It is characterized by:

(Function) The present invention measures the chip by bringing a probe needle into contact with it, detects the needle mark at the time of measurement, and inspects the electrical contact status of the probe needle from this needle mark.
In order to decide whether or not to conduct the test based on the test results,
This not only reduces defective inspection time and improves the reliability of semiconductor wafer inspection results, but also reduces erroneous inspections in which non-defective products are determined to be defective, and has the effect of improving yield.

(Example) An example of the semiconductor wafer measuring method of the present invention will be described below with reference to FIGS. 1 to 3.

Under the control of the control unit 10 shown in FIG.
After positioning the wafer 1 by moving the wafer 1 in the X-axis, Y-axis, Z-axis directions, and in the circumferential direction around the Z-axis center using the driving mechanism (system) 12, the wafer 1 is moved on the mounting table 3 shown in FIG. , the semiconductor wafer 1 to be measured is temporarily fixed by vacuum suction. Next, under the control of the control section 10, the probe card needle 2 is brought into contact with the pad 5 of the chip 4. The position at this time is O as shown in Figure 1a.
Point. The position where the needle mark formed on the pad 5 due to the above contact is recognized is defined as point P. That is, the first
As shown in FIG. b, when the probe card needle 2 comes into contact with the tip 4, a needle mark R is added to the pad 5. The tip 4 to which the needle mark R has been added is moved to a position P where it is recognized by the recognition device 13 shown in FIG. This movement is performed on the X-axis, which moves the drive mechanism 12, that is, the mounting table 3, according to instructions from the control unit (system) 10.
Move to the specified position using the Y-axis motor.

Through such operations, the readout information of the specified area (condition) Q already stored in the memory 14 shown in FIG. 2a and the needle added by the above means to the actual area shown in FIG. 2b The area of the added needle mark R obtained by recognizing the mark at position P by the recognition device 13 is compared. At that time, as shown in Fig. 2b, the needle mark R is placed within the designated area Q.
If the area of the needle mark R is within a predetermined tolerance, the recognition device 13 determines that the contact between the probe card needle 2 and the pad 5 is appropriate. This result is stored in memory 14. If the judgment information is "appropriate contact," it will be possible to test continuously.

Similarly, as shown in FIG.
3, the recognition device 13 determines that there is "inappropriate contact" between the probe card needle 2 and pad 5. Of course, at this time, a signal indicating that the test by the tester 15 is not possible is transmitted to the control unit 10.
It is also possible to automatically correct the position by emitting a signal from the controller 10 or by controlling the mounting table 3 with a microprocessor or the like of the control unit 10.

(Effects of the Invention) The semiconductor wafer measurement method of the present invention is carried out through the process described above, so that after adding needle marks to all the chips over several hundred chips, conventionally an operator would have to use a microscope, monitor TV, etc. However, in the present invention, such waste can be eliminated. Therefore, by performing the test while checking the contact status of the probe needle, the reliability of the test results can be confirmed each time, and the reliability of the semiconductor wafer measurement method is immeasurably improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIG.
FIG. 3 is a schematic diagram for explaining the needle trace inspection by means of a diagram, and FIG. 3 is a block diagram of the apparatus shown in FIG. 1. DESCRIPTION OF SYMBOLS 1... Semiconductor wafer, 2... Probe card needle, 3... Mounting table, 4... Chip, 5... Pad, 10... Control unit, 11... Measurement mechanism, 12...
... Drive mechanism, 13 ... Recognition device, 14 ... Memory,
15... Tester, Q... Specified area, R... Needle mark.

Claims (1)

[Claims] 1. In a method of electrically measuring each chip in a semiconductor wafer to be measured by sequentially contacting each chip with a probe needle, a step of detecting the trace of the contact needle by the probe needle after electrically measuring each chip, and detecting by this step. A method for measuring a semiconductor wafer, comprising the steps of: inspecting the contact status of the probe needle at the time of the measurement from the needle traces made; and confirming the measurement result of the chip from the inspection result of this step. .