JPH0669053B2 - Probing machine - Google Patents

Description

The present invention relates to a marking device for a probing machine for measuring and inspecting electrical characteristics of semiconductor elements such as integrated circuits arranged in a lattice on a wafer.

As is well known, in a propping machine, a wafer 1 as shown in FIG. 1 is set in a predetermined direction on a suction table provided on an XY table and arranged on the wafer 1 in a lattice pattern. The electrical characteristics of a large number of elements 2 are measured and inspected one by one by a tester connected to a probe card having a stylus at the same position and arrangement as the electrodes of the elements, and defective elements are marked with ink or the like. The defective element is removed according to this mark in a later step.
In such a probing machine, a conventional method of marking a defective element on a mark is such that each stylus of a probe card comes into contact with each electrode of the element and its electrical characteristics are measured and inspected by a tester connected to the probe card. Immediately after that, the marking pen was inserted from the center of each stylus at that position and a mark was attached.

However, as the integration and density of semiconductor devices have increased, the number of electrodes has increased.
When products having 0 or more are produced, it is difficult to apply the marking method as described above.
That is, when measuring the electrical characteristics of an element having a large number of electrodes, it is necessary to use a probe card having a large number of stylus in the same arrangement as the number of electrodes,
Since many stylus are densely provided in a narrow space, it becomes difficult to insert the marking pen from the central portion. Even if the marking pen can be inserted from the narrow space, the marking pen may come into contact with each stylus and displace the tip position of the stylus, or ink may adhere to the stylus. Occurrence is unavoidable. In the case of an element to be inspected, such as a photodiode array, whose characteristics need to be inspected while the element is exposed to light, the marking pen blocks the light so that the element is exposed to light. There was a drawback that it could not be measured because it was not hit.

Therefore, as another marking method, each element is measured and at the same time, the address of that element [(x ₁ , y _{1 in} Fig. ₁ ,
(X ₂ , y ₂ ) ... (xn, yn)] and whether or not the device is a defective device are stored, and after the measurement of all devices on the wafer is completed, the wafer is separately provided. There is a method of marking according to the memory by the dedicated marking machine.For this, the wafer is correctly fed and driven in the marking machine in the order and direction that is absolutely confident with the time when the measurement is stored. It is indispensable that the position of the element, for example, (x ₁ , y ₁ ) does not change. Another marking method using a memory is as follows.

The suction table is moved in the XY directions, and the operator aligns the center of the suction table with the center of the fixed probe card while looking at the microscope. The propping machine stores the center coordinates of the suction table at the matched position.

The wafer is placed on the suction table, the diameter of the wafer placed on the suction table is measured while moving the suction table, and the center position of the wafer is determined by moving the suction table and measuring three points on the outer circumference of the wafer. As a result, the distance between the suction table center and the wafer center is also obtained.

Align the position of the probe card and the semiconductor element. The probing machine assumes that the center of the probe card coincides with the center of the semiconductor device, and divides the wafer according to the size of the semiconductor device that is known in advance based on that position.

By reading the coordinates of the center of the suction table, the distance between the center of the suction table and the center of the probe card is known, and the distance between the center of the suction table and the center of the wafer is known, so that classification is possible. Further, since the diameter of the wafer is known, the shape of the semiconductor element around the wafer can be known.

In this way, the map (chip arrangement on the wafer) is completed. However, the operator alignment error (above),
There is a wafer size measurement error (above), which is not always accurate.

When the wafer is transferred between the measurement cable and the marking table, the maps have to be created in different tables. If a map is created in a different table, an error will occur in the process different from the above. This error occurs on the order of a few tenths of a millimeter. Therefore, when the semiconductor element size is as small as about 1 mm or less, the maps generated between the tables may differ (map shift). In a probing machine equipped with a memory, each element is measured on the measurement table, and at the same time, the address of the element [(x ₁ , y ₁ ), (x ₂ , y ₂ ) in Fig. ₁ (xn, y
n)] and whether or not the element is a defective element, and after the measurement of all the elements on the wafer is completed, the wafer is marked according to the memory by a separately provided marking table. When the map shift occurs, there is a drawback that the defective element cannot be accurately marked. It should be noted that when a defective element occurs during measurement, a method of marking by moving the stylus is not inconceivable, but if the stylus that requires very strict positioning is moved each time a defective element occurs, It is technically very difficult to move because there is a risk of misalignment and that each probe of the probe card and the control unit are connected by as many wires as there are probes. There are drawbacks.

The present invention improves on these points and provides a device for reliably marking with a simple mechanism. An embodiment of the present invention will be described below.

FIG. 2 is a plan view of a probing machine equipped with the marking device of the present invention. A large number of pre-measurement wafers stored in the cassette 4 are guided one by one to the conveyor belt 5 along the arrow in the figure. It is conveyed and supplied to the pre-alignment apparatus 6. In the pre-alignment apparatus 6, the wafer 1 supplied from the cassette 4 in any direction
Are aligned in a certain direction as shown by the chain line in the figure. The mechanism of the pre-alignment device 6 is described in detail in Japanese Patent Publication No. 56-34092 “Wafer Positioning Device” of the applicant of the present application, and therefore the description of the structure is omitted here.

The wafer 1 positioned by the pre-alignment device 6 is sucked at the position A by the wafer suction device 7 which is movable between A and B and moved to the position B. At the position B, a suction table 9 vertically movably and rotatably provided on the XY table 8 stands by at a position directly below the wafer suction device 7, and the wafer 1 released from the wear suction device 7 is held. Vacuum suction is performed on the suction table 9. In the figure, in order to clearly show the suction table 9, the suction table 9 is not directly below the wafer suction device 7, but is shown in a state of being moved in the Y direction.

The wafer 1 sucked and fixed on the suction table 9 is XY.
The table 8 is moved to the C position, and at this position, the suction table 9 is finely moved in the X and Y directions or slightly rotated according to the detection result by the optical method, so that the wafer 1 is precisely positioned. . The wafer 1 thus positioned is a measurement area D by the XY table 8 based on previously input data.
A large number of stylus 11 of the probe card 10 which has been moved to the position and precisely needled with each electrode of the element by the microscope (not shown) comes into contact with each electrode of the element at the D position, as shown by arrows in FIG. 1, for example. Like (x ₁ , y ₁ ), (x ₂ , y ₂ ) ...
Perform measurement inspection in the order of (xn, yn). At that time, if there is a defective element, the address of the element, for example, (xm, ym) is stored by the storage device of the control unit. When the measurement of all the elements is completed, the wafer is moved to the E position where the marking device 12 stands by in a state where the wafer is fixed to the suction table 9 by suction, that is, in the same state as when being measured without changing the position and direction. According to a command from the control unit, the defective element stored in advance stops at a position directly below the marking pen, and the suction table 9 rises or the marking device 12 descends, and the element becomes the element. Mark the surface.

As shown in FIG. 3, for example, the marking device 12 has an ink fountain 14 attached to one end of an arm 13 fixed to a base of a probing machine, and a marking pen at the tip thereof.
The one that holds 15 is used. A device shown at 16 in FIG. 3 is a mark sensor, that is, a detector for detecting whether or not a defective element is surely marked by the marking device 12, for example, for detecting the presence or absence of reflected light of irradiated light. It is possible to detect whether or not the mark is added by. One mark sensor may be provided in the vicinity of the marking pen 15 as shown by 16, and the presence or absence of the mark may be detected immediately after the mark is attached. Two pieces may be provided one by one or a plurality of pieces apart from each other at the front and the rear, and the presence or absence of the mark may be detected when the marked element is sent under the element. In this case, the reason why two mark sensors are provided before and after is that the wafer may be sent from left to right or from right to left as shown by the arrow in FIG. If it is detected by the mark sensor that the defective element is not marked, there is no ink in the ink fountain 14, or, for example, the contact between the marking pen 14 and the element is insufficient. Since it is assumed that such a trouble has occurred, by stopping the operation of the apparatus and canceling the trouble, it is possible to prevent in advance a defective nest from being mixed in a good product in a subsequent process.

Thus, the wafer 1 in which all defective elements are marked
Is operated to the F position while being fixed to the suction table 9 by suction. At the F position, a wafer suction device 19 that can move between F and G is on standby, and the wafer 1 for which measurement and inspection has been completed is sucked, conveyed to the G position, and released. The released wafer 1 is carried by the carrying belt 20 along the arrow in the figure and is housed in the wafer housing cassette 21 to complete the measurement.

As described above, according to the probing machine of the present invention, the same suction table operates at the measurement inspection position by the stylus and the marking position to perform marking,
There is no problem with wafer alignment error between tables,
Only the feeding error of the suction table causes the displacement of the marking pen position. Therefore, a highly accurate marking operation is possible. Furthermore, the present invention utilizes the wafer's X / Y direction drive mechanism and the like that a normal probing machine originally possesses, and by adding a few mechanical parts, it is possible to make a marking without error and its confirmation function. It is possible to add, and it brings about an extremely great practical effect in reliability and economical efficiency.

[Brief description of drawings]

1 is a plan view of a wafer, FIG. 2 is a plan view of the present invention, and FIG. 3 is a view taken along the line III-III in FIG. 1: Wafer, 2: Semiconductor element 3: Defective element mark, 8: XY table 9: Suction table, 10: Probe card 11: Stylus, 12: Marking device 16, 17, 18: Mark sensor

Claims (1)

[Claims] 1. A probing machine for sequentially measuring the electrical characteristics of semiconductor elements arranged in a grid on a wafer through stylus in contact with each electrode of the semiconductor element, and a plurality of wafers to be inspected are accommodated. A supply cassette, a pre-alignment device for aligning a wafer sent from the supply cassette in an arbitrary direction through a transfer means in a fixed direction, and a suction device for moving the wafer in the XY directions while suction-fixing the wafer thereon. A table; a positioning means for positioning the wafer on the suction table; a stylus for contacting the electrodes of the semiconductor elements on the wafer on the suction table for measurement inspection at the measurement inspection position; A memory means for storing the position and the position of the defective element of the semiconductor element found by the measurement inspection with the stylus, and the marking position. The marking pen that marks the defective elements stored in the memory means on the wafer after the measurement is completed, the detection mechanism that detects the presence or absence of marking of the defective elements on the wafer, and the marking pen A discharge cassette for storing a plurality of wafers, and the suction table suction-fixes the wafer sent from the pre-alignment device through the transfer means and moves it to the measurement inspection position to perform the measurement inspection. After that, the probing machine is characterized in that the wafer is sucked and fixed as it is and moved to the marking position to perform the marking.