JPH0766249A - Wafer testing device with probe contact state controller - Google Patents

Abstract

PURPOSE:To obtain a device with which the mounting state of a probe card can be adjusted automatically and also a probe test can be conducted in a highly efficient manner by a method wherein the inclination and the height of mounting position of probe card is adjusted in such a manner that the amount of ascending of wafer is suppressed to the minimum when the tip of all probes is brought into contact with a pad. CONSTITUTION:Before the probe test of the new chip on a wafer 2, the position of the wafer 2 is moved up every time, and the state wherein the tip of a probe comes in contact with the corresponding pad is detected. Moreover, when the amount of rising of the wafer 2 exceeds the prescribed value when the tip of all probes is brought in a contact state, the inclination and the height of the mounting position of a probe card 3 are calculated in order to suppress the rising amount of the wafer 2 to the minimum when the tip of all probes is in contact state. The result of calculation is sent to an adjustment mechanism 9, and a probe test is performed again in the state wherein the probe card mounting state is corrected. A control mechanism, with which the abovementioned operations are automatically conducted, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe test of a wafer, in which the tip of each probe and the corresponding pad on the chip of the wafer adjust the mounting condition of the probe card to the test equipment. The present invention relates to a wafer test apparatus with a probe contact state control function having a function of automatically controlling so that a test can be executed most efficiently.

[0002]

2. Description of the Related Art FIG. 3 is a schematic side sectional view showing a conventional wafer test apparatus, and FIG. 4 is a flow chart of a probe test by the conventional wafer test apparatus. In FIG. 3, 1 is a wafer stage on which a wafer can be moved accurately as instructed, 2 is a wafer, 3 is a probe card, 4 is a fixed plate on which a probe card is mounted, and 5 is a contact (probe contact state) energization detection. Reference numeral 6 is a wafer prober, 7 is a memory tester (testing device), and 8 is a display panel for displaying the contact state (contact) of all probes.

A probe card 3 for a test target product is attached to a fixed plate 4 of a wafer prober 6. As shown in FIG. 4, when the wafer stage 1 on which the wafer 2 is placed is raised little by little, the contact state of all the probes (which probe is being energized, that is, which probe is in contact, through the energization detector 5). (Whether it is not in contact) is displayed on the display panel 8 to inform the test operator. The operator looks at the display panel and, while memorizing the contact state of each probe, determines whether or not the amount of rise of the wafer (stage) required until all the probes come into contact is within the standard. When the amount of stage rise is within the standard, that is, when it is normal, the wafer stage 1 moves the position of the wafer 2 laterally and puts the next chip at the probe test position, and the probe test is performed normally. As much as possible, the test equipment repeats the above-mentioned operations to
A probe test is sequentially performed on all the chips inside. If all the probes do not come into contact with each other unless the stage rise amount is larger than the standard, that is, if there is an abnormality, the probe card 3 is replaced or the fixed plate 4 is adjusted.

[0004]

In the above-mentioned conventional test apparatus, all probes are stably brought into contact with the pads on the chip of the wafer when, for example, the state of the probe changes during the probe test of the wafer. This makes it impossible to continue the probe test due to poor electrical contact between the wafer and the probe.

According to the present invention, the test apparatus itself can automatically adjust the mounting state (inclination, height) of the probe card so that the above-mentioned problems do not occur, and the probe test can be performed efficiently. An object of the present invention is to provide a wafer test apparatus with a probe contact state control function that can be executed well.

[0006]

In order to solve the above-mentioned problems, in the present invention, the tips of a large number of probes are connected to the corresponding connection pads on the chip of the wafer or inside the chip specially prepared for inspection. In order to test the wafer by contacting the pads and inspecting whether or not the desired voltage is detected for each pad, in the mounting part of the probe card of the test equipment, the inclination and height of the mounting position In addition to installing the adjustment mechanism, each time prior to the probe test of a new chip on the wafer, the position of the wafer is first raised, and as the rise is detected, the tip of the probe detects contact with the corresponding pad. , If the amount of rise of the wafer when it is confirmed that the tips of all the probes have contacted the corresponding pads, if the wafer rise amount is less than the specified value, If the wafer rise amount exceeds the above specified value when the tips of all the probes are in contact with each other, the wafer rise amount and the probe tips detected according to the rise and the pads contact each other. From the increased number of parts and contact points, calculate the inclination and height of the probe card mounting position so as to minimize the amount of wafer rise when the tips of all probes are in contact,
It is decided to provide a control function for automatically executing various operations of sending the calculation result to the adjusting mechanism and performing the probe test again with the corrected probe card attached.

[0007]

[Function] The tip of each probe has variations such as slightly longer or shorter than the surroundings. Therefore, when the wafer is raised, there are variations in those that come into contact with the pads of the chip early and those that come into contact with the pads after being raised considerably. However, if the variation becomes too large, various problems may occur, for example, the tip of the probe once in contact may be pushed too far and protrude from the pad to the outside to become non-contact again, or in some cases, break. Therefore, it becomes necessary to set a maximum limit value for the amount of rise of the wafer until all the probes come into contact with each other. By taking the above means, the amount of rise of the wafer until all the probes come into contact with each other can be suppressed to a predetermined value or less.
For example, in the conventional device, at least in the case where the probe test can be continued by adjusting the fixed plate, the operator is troubled with the manual adjustment of the probe card mounting state due to the automatic control function of the device of the present invention. Without it, the test can be done quickly. When only one tip of the probe is broken (even if none of the tips of the other probes are broken) and becomes very short, the probe card is used to position the probe tip even in the test apparatus of the present invention. Must be replaced with another probe card that does not vary much, but in such a special case, the wafer stage repeatedly moves up and down with respect to the same chip, so the operator can tell immediately. . Therefore, the probe test can be efficiently performed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where a probe test of a semiconductor memory wafer is performed by the apparatus of the present invention will be described as an example.

In many cases, a probe test of a semiconductor memory is carried out by placing a wafer in a high temperature state or a low temperature state defined by a standard. Thus, the temperature of the wafer is typically set to an inspection temperature that is significantly different from the ambient temperature, so that when the probe test is initiated, the temperature of the probe card is localized due to heat radiation and heat conduction from the probe. Repeated rising and falling. Under such circumstances, the height and inclination of the probe card may fluctuate, and there is a high possibility that electrical contact failure will occur between the tip of the probe and the corresponding pad on the chip of the wafer. The test apparatus according to the present invention can efficiently execute the probe test even in the above case.

In the embodiment of the present invention described below, the contact between the probe tip and the pad, which is similar to that used in the above-mentioned conventional example, is determined to be contact when the current is in the energized state and non-contact when the current is not energized. We decided to detect the state of contact between the two by the accepted method. In addition to the above-mentioned energization detection method, there are methods of detecting the contact state, such as a method of judging from the image information and a method of judging from the pressure value applied to the tip of the probe.

FIG. 1A is a top view showing a state in which a tilt height adjusting mechanism 9 at a probe card mounting position is attached to a fixed plate 4 of a wafer prober 6 according to an embodiment of the present invention.
(B) is a schematic side sectional view of the entire embodiment. In the figure, 9 is the tilt height adjusting mechanism of the probe card mounting position as described above, 10 is the controller for the automatic control function according to the present invention, 11 is the contact state (contact) detection function,
Other reference numerals are the same as those in FIG. The tilt height adjusting mechanism 9 at the probe card mounting position has three adjusting protrusions A, B, and C, and changes the protruding state of these protrusions to perform arbitrary adjustment.

FIG. 2 is a flow chart when performing a probe test according to the embodiment of the present invention. First, a probe card suitable for the type of semiconductor memory to be tested is attached to the fixed plate 4 through the tilt height adjusting mechanism 9. The wafer stage 1 on which the wafer 2 is placed is raised, and during the ascending period, the controller 10 receives the information regarding the contacts of all the probes from the contact detection function 11 and stores the information in the built-in memory. It is determined whether it is inside. If it is within the standard, after performing a probe test, the wafer stage 1 is moved laterally until the next chip comes to the test position, and the above-mentioned operations are repeated. If no abnormality is detected on the way, the above operation is repeated until the probe test is completed for all the chips. If the controller 10 determines that the probe tips have a large variation and is out of the standard (that is, an abnormality is detected), the controller 10 once lowers the wafer stage 1 and adjusts the mounting position of the probe card 3 on the wafer 2 so that all the probe tips are attached. Calculates the amount for correcting the inclination and height so that the variation when the pad contacts the corresponding pad on the chip becomes as small as possible, and the calculated amount is used as a correction signal in the inclination height adjusting mechanism 9 of the probe card mounting position. After being sent, the protrusion amounts of the three adjusting protrusions A, B, and C are adjusted, and then the above-described operations are repeated from the rising of the wafer stage 1.

[0013]

As described above, according to the present invention, when performing a probe test on a wafer in a wafer testing apparatus, an operator visually monitors the contact state of the probe as in the conventional case, and detects the probe contact state. It is no longer necessary to memorize the information to determine whether the probe tip varies or not, and the operator does not have to worry about the troublesome adjustment work of the probe card mounting state, so that the probe tip is very efficient and reliable. The probe test of the wafer can be performed while it is in contact with the wafer.

[Brief description of drawings]

FIG. 1 (a) is a top view of a state in which a probe card attachment position adjusting mechanism is attached to a fixing plate according to an embodiment of the present invention, and FIG. 1 (b) is a schematic side sectional view of the entire embodiment.

FIG. 2 is a flowchart when performing a probe test according to an embodiment of the present invention.

FIG. 3 is a schematic side sectional view of a conventional wafer test apparatus.

FIG. 4 is a flowchart when a probe test is performed by a conventional wafer test apparatus.

[Explanation of symbols]

1 ... Wafer stage, 2 ... Wafer, 3 ... Probe card, 4 ... Fixed plate, 5 ... Contact current detection unit, 6 ... Wafer prober, 7 ... Memory test device, 8 ... Contact display unit, 9 ... Tilt height adjustment mechanism , 10 ... Controller, 11 ... Contact detection function.

Claims (1)

[Claims] 1. The desired voltage is detected for each pad by bringing the tips of a large number of probes into contact with a corresponding connection pad on a chip of a wafer or a pad inside a chip specially prepared for inspection. In order to perform a probe test of the wafer to inspect whether or not it is tested, a mechanism for adjusting the inclination and height of the mounting position is installed at the mounting part of the probe card of the test equipment, and a probe test of a new chip on the wafer is performed. Prior to each time, first raise the position of the wafer,
If the tip of the probe detects that the tip of the probe is in contact with the corresponding pad as it rises, and it is confirmed that the tips of all the probes are in contact with the corresponding pad, the amount of rise of the wafer is below a predetermined value. For example, if that is the case, perform a probe test for that chip, and if the amount of rise of the wafer when the tips of all the probes are in contact with each other exceeds the above specified value, the amount of rise of the wafer and Due to the detected contact area between the probe tip and the pad and the number of contact points, the tilt and height of the probe card mounting position should be minimized to minimize the wafer rise amount when all probe tips are in contact. Control function that automatically performs various operations such as calculating the height and sending the calculation result to the adjustment mechanism to perform the probe test again with the corrected probe card installed. Probe contact state control function wafer testing apparatus, characterized in that provided.