JPH04340241A - Inspection apparatus of semiconductor wafer - Google Patents

Abstract

PURPOSE:To enhance the reliability of the title apparatus and to make an operation efficient when chips on a semiconductor wafer are inspected by using a probe needle. CONSTITUTION:The following are installed in the title apparatus: a driving mechanism 2 which moves a wafer-mounting stage 1; a recognition means 3 which recognizes the needle trace, of a probe needle, formed on an electrode pad on a chip; memory 31 which has stored the data of a designated region and the setting range of an area; and a control part 4 which drives and controls the driving mechanism 2. The mounting stage 1 is set in such a way that a prescribed electrode pad 6 on the chip is placed in an inspection position; the probe needle is brought into contact with and pressed to the electrode pad 6 here; the pad is measured electrically. After that, the electrode pad 6 is placed in a recognition position; it is judged by using the recognition means 3 whether the region of the needle trace is included in the designated region or not and whether its area is situated within the setting range. In the case of 'good', a next chip is inspected; in the case of 'bad', the inspection operation is stopped.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer inspection apparatus.

0002

2. Description of the Related Art Generally, when IC chips are obtained from a semiconductor wafer, each chip is inspected before it is separated, that is, when it is assembled into a wafer.

Conventionally, in order to perform such an inspection, an operator would touch an electrode pad within the chip to one chip out of, for example, several hundred chips formed in a matrix on a wafer. Confirm that the probe needle is in the correct position by making contact with it using a microscope, monitor TV, etc., and trust the mechanical precision of the semiconductor wafer measuring device (including the precision of the automatic recognition device) and the repeatability of the chip. On the assumption that the probe needle is in accurate contact with the pad, the quality of the chip is determined by a tester connected to the probe needle.

[0004] When a chip is determined to be defective through the above determination process, there are two questions: (1) Is the chip truly defective? (2) It is determined that the chip is defective because the contact state of the probe needle with the electrode pad surface of the semiconductor wafer is poor. It is not possible to determine whether this was done or not. Therefore, for example, if chips continue to be defective during actual testing, the test target is returned to the chip that passed before the defective chips continued, and the probe needle row is brought into contact with the returned chip again to perform the test. I'm redoing it. In this case, if the measurement result is the same as the previous result, chips that are consecutively determined to be defective are treated as defective chips.

[0005]

[Problems to be Solved by the Invention] However, in the conventional inspection method, the operator must periodically check the state of contact with the electrode pad using a microscope, etc., and automatic inspection equipment is not used. However, it is not efficient because it requires a lot of effort on the part of the operator.

[0006]Also, if the probe needle comes into contact with the boundary line of the specified area of the electrode pad, the inspection condition will be unstable, but since the inspection will continue in this case as well, the reliability of the inspection results will be increased. The problem is that it is low.

The present invention has been made under the above circumstances, and its object is to provide an apparatus capable of efficiently and highly reliable testing of semiconductor wafers.

[0008]

[Means for Solving the Problems] The present invention provides an apparatus for electrically measuring chips by bringing probe needles into contact with each chip of a semiconductor wafer, and inspecting the quality of the chips based on the measurement results. Recognizes the needle mark caused by the needle and determines whether the recognized needle mark is within a prespecified area, and also determines whether the area of the needle mark is within a preset setting range. The present invention is characterized in that a recognition means is provided for determining the contact state of the probe needle based on these determination results.

[0009]

[Operation] For example, each time each chip is inspected, or after a predetermined number of chips have been inspected, the wafer is moved to a predetermined position, and the region and area of the needle trace are determined by the recognition means. It is determined whether the probe needle is in the set range or not, and if it is determined that the contact state of the probe needle is good, the inspection is continued and it is determined to be defective. If so, the inspection will be canceled.

0010

Embodiment FIG. 1 is a diagram showing an apparatus according to an embodiment of the present invention. a drive mechanism 2 for moving along the Z-axis and rotating around the Z-axis; a recognition means 3 for recognizing needle marks formed by probe needles (to be described later) on electrode pads of chips on the wafer W; The apparatus includes a control section 4 that issues control commands to the drive mechanism 2 and the recognition means 3.

The drive mechanism 2 moves the mounting table 1 so that the electrode pads of each chip are sequentially contacted with probe needles, which will be described later, and also moves the mounting table 1 so that the electrode pads 6 of the chips 5 are brought into contact with the probe needles, which will be described later. - Function to drive the mounting table 1 to move between the inspection position A where it is contacted by the probe needle and the recognition position B where the trace of the needle is recognized and the quality of the contact state of the probe needle is determined. have.

The recognition means 3 has a function of recognizing the needle mark on the pad 6 and detecting its region and area (size);
The function is to determine whether the detected area is included in the specified area stored in the memory 31 and to determine whether the detected area is within the set range stored in the memory 31. We are prepared. As for the area of the needle mark, it is desirable to set a lower limit and an upper limit in advance, and to judge that the area is appropriate if the size is between them.

Next, a description will be given of how each chip 5 of the wafer W is inspected using the above-described apparatus. When inspecting the chip 5 shown in FIG. 2 among the chips on the wafer W, the predetermined electrode pad 6 of the chip 5 is positioned below the probe needle 7 shown in FIG. 3, that is, at the inspection position A. The drive mechanism 2 is driven to move the wafer W.

Subsequently, the mounting table 1 is raised by the drive mechanism 2, and the probe needle 7 is brought into contact with and pressed against the electrode pad 6 as shown on the right side of FIG. 3, and an electrical measurement is performed using a tester (not shown). After that, in order to recognize the pad 6 of the chip 5 and the trace of the probe needle 7, the mounting table 1 is lowered by the drive mechanism 2 to separate the electrode pad 6 from the probe needle 7, and then
The wafer W is moved so that the electrode pad 6 is located at the recognition position B. Note that in the electrical measurement, the traces of the probe needle 7 are actually left on the four electrode pads 6 on one chip 5, but for the sake of explanation, only one electrode pad 6 is left.
I will explain about the needle marks.

Then, the recognition means 3 detects the probe needle 7.
The area of the needle mark R is recognized, the area and area (size) of the needle mark R are detected, and the area of the needle mark R is stored in the memory 31, as shown in FIG. 4(a). It is determined whether the area of the needle mark R is within the set range, for example, the range of S1 to S2. (b) in Figure 4
), if the region of the needle mark R is located within the specified region Q and its area is within the set range, it is determined that the contact state between the probe needle 7 and the electrode pad 6 is good. Then, the wafer is moved so that the next electrode pad is located at inspection position A. Further, if at least one of these conditions is not satisfied, for example, if the area of the needle mark R is outside the designated area Q, as shown in FIG.
It is determined that the contact state between the electrode pad 6 and the electrode pad 6 is inappropriate, and the subsequent test is discontinued.

In the above embodiment, the program for each chip is
The state of contact between the probe needle and the electrode pad is recognized each time the probe needle is inspected, but the device of the present invention can be used during the process of inspecting each chip on a semiconductor wafer. However, the present invention is not limited to the embodiments as long as the contact state is determined based on the region and area of the trace of the probe needle.

[0017]

As described above, according to the present invention, when inspecting chips on a semiconductor wafer, the recognition means identifies the probe needle and the electrode pad based on the region and area of the probe needle trace. Since the contact state is judged, the contact state can be accurately grasped, and the contact state can be monitored without the need for visual observation using a microscope or other means by the operator, resulting in high reliability. In addition, efficient inspection can be performed. In addition, since the contact state of the probe needle can be automatically determined by the recognition means, it is not troublesome to perform this determination frequently. - Situations such as the needles coming into contact can be quickly detected.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a wafer is placed at an inspection position and a recognition position.

FIG. 3 is an explanatory diagram showing how a chip is inspected using a probe needle.

FIG. 4 is an explanatory diagram showing conditions for determining a contact state with respect to a trace of a probe needle.

[Explanation of symbols]

1 Wafer mounting table 3. Recognition means 5 Chip 6 Electrode pad 7 Probe needle Q Specified area R needle mark W Wafer

Claims (1)

[Claims] 1. In a device that makes electrical measurements by bringing a probe needle into contact with each chip on a semiconductor wafer, and then inspects the quality of the chip based on the measurement results, the traces made by the probe needle can be recognized and recognized. It is determined whether the needle mark is within a prespecified area, and also whether the area of the needle mark is within a preset setting range, and the probe needle is adjusted based on these judgment results. 1. A semiconductor wafer inspection device characterized by comprising a recognition means for determining a contact state of a semiconductor wafer.