KR101563825B1 - Wafer test machine including laser cleaning function - Google Patents

Abstract

Disclosed is a wafer inspecting device for inspecting a semiconductor wafer. The wafer inspecting device comprises: a device body which restricts a wafer inspecting chamber in the device body wherein a probe is introduced onto an upper portion of the wafer inspecting chamber; a wafer chuck which fixes a wafer in the device body; a mobile unit which enables the probe and the wafer to selectively contact each other by moving the wafer chuck into the device body; and a laser generating device which irradiates a laser beam onto the probe by generating the laser beam in the device body.

Description

[0001] WAFER TEST MACHINE INCLUDING LASER CLEANING FUNCTION [0002]

The present invention relates to a semiconductor wafer inspection equipment, and more particularly, to a wafer semiconductor wafer inspection equipment including a function of cleaning a probe contact portion of a probe card used for wafer inspection with a laser.

In the semiconductor manufacturing process, the wafer inspecting process is a process of judging whether or not the semiconductor device is good by determining the electrical characteristics of the device after the semiconductor device is formed on the wafer, and is very important in determining the yield of the semiconductor device. Process. This wafer inspection process is performed through wafer inspection equipment.

To inspect the semiconductor devices fabricated on the wafer, the wafer is moved from the inside to the outside of the wafer cassette and loaded onto a wafer chuck on a moving stage for wafer inspection. The movable stage is usually composed of three axes of x, y, and z, and precisely controls the wafer to be transferred to a very precise position so that accurate inspection of the wafer can be performed. The wafer inspection equipment conducts inspection by electrically contacting an inspection board, called a probe card, with the wafer. The probes present on the probe card are brought into precise contact with the contact pads present on the surface of the device on the wafer and then various electrical signals are sent from the tester to the device to determine the electrical characteristics of the device, .

At this time, the probe card comes into contact with a large number of wafers. Such continuous contact causes contamination of the probe contact portion. If the contamination of the probe contact portion increases, the contact resistance increases upon contact with the element on the wafer, which interferes with the smooth flow of the inspection signal, which may cause the good element to be treated as defective. That is, even if the device is good, the device is defective due to contamination of the probe contact portion, which results in a problem that the inspection yield is lowered.

To solve this problem, a technique for installing a cleaning pad in a wafer inspection apparatus has been proposed. According to this technique, after the wafer is inspected a predetermined number of times, the cleaning pad is moved to the lower side of the probe card by using the transfer stage, the cleaning pad is moved up and down along the z axis and the cleaning pad is brought into contact with the probe, A cleaning operation for removing the material is performed. In this cleaning operation, abrasive particles having high hardness are applied on the cleaning pad, and these abrasive particles finely grind the probe contacts to remove contaminants on the probe contacts.

However, in the method of mechanically cleaning the probe contact portion using the cleaning pad as described above, as the number of times of cleaning increases, abrasion occurs in the probe contact portion, and eventually the probe having a very sharp shape is made dull. If the probe is severely dented, the probes will not contact the wafer smoothly and eventually the probe card must be replaced. Recently, as the number of high frequency ICs and ultra-large-scale device tests, which are highly sensitive to probe card contact, have increased, the replacement cycle of the probe card has become very short. In addition, the price of the probe card is very expensive, so there is a need for a new probe cleaning method that can maintain the state of the initial probe card for a long time without wear of the probe.

While maintaining the probe without abrasion allows the probe to contact the wafer contact pads in a deep and effective manner, it is possible to maintain the best inspection yields, but the mechanical cleaning method using conventional cleaning pads is not suitable for high probe card life And the inspection yield is gradually reduced due to a decrease in contact performance due to probe abrasion.

Korean Patent Publication No. 10-2010-0024062 (Mar. 05, 2010)

It is an object of the present invention to provide a semiconductor wafer inspection apparatus capable of automatically performing a laser cleaning operation on a probe contact portion in a wafer inspection equipment.

According to an aspect of the present invention, there is provided a wafer inspection apparatus for inspecting a semiconductor wafer, the wafer inspection apparatus comprising: a machine body for limiting a wafer inspection chamber having a probe on the upper portion thereof to the inside; A wafer chuck for holding a wafer in the apparatus main body; A moving unit for moving the wafer chuck in the apparatus main body to selectively contact the probe and the wafer; And a laser generator for generating a laser beam in the main body of the apparatus and irradiating the probe with a laser beam.

According to one embodiment, the moving unit comprises an XY moving stage for moving the wafer chuck in the X and Y axes, a wafer chuck elevator for moving the wafer chuck in the Z axis direction on the XY moving stage, Wherein the laser beam generator is installed on the XY moving stage so as to be spaced apart from the wafer chuck and is moved in a direction facing up and down with the probe by the XY moving stage.

According to one embodiment, the laser beam generator is driven up and down in the Z-axis direction by a laser cleaning platform operated independently of the wafer chasper.

According to an embodiment, the laser beam generator irradiates a laser beam of a parallel light type toward the probe.

According to an embodiment of the present invention, a laser beam diaphragm having a plurality of laser beam apertures formed in at least one of a shape and a size is provided on the upper side of the laser beam generator, and the laser beam diaphragm uses the plurality of laser beam apertures And adjusts at least one of the size and shape of the laser beam irradiated on the probe.

According to an embodiment of the present invention, a dust collecting device for collecting and permanently removing dust generated during laser cleaning of the probe is provided on the upper side of the laser beam generating stand.

According to one embodiment, the laser beam generator has a laser window having a laser beam transmittance of 99% or more in the laser beam output area on the upper surface.

According to one embodiment, the laser beam emitted from the laser beam generator is in the range of 200 to 1500 nm, the laser beam emitted from the laser beam generator is in the form of a pulse wave, and the peak output of the pulse is 10 ⁶ W or more .

According to one embodiment, a laser power supply device, a laser cooling device, and a laser control device for controlling the laser beam generating device are located outside the apparatus main body.

The apparatus for inspecting a wafer according to the present invention includes a laser beam generator for generating a laser beam for removing surface contaminants on a probe contact surface, the laser beam generator irradiating the laser beam toward the probe card, So that effective cleaning can be performed without worn out of the probe. Preferably, the apparatus for inspecting a semiconductor wafer of the present invention may further include a dust collecting device for effectively removing fine dust particles generated during laser cleaning, and a laser beam iris for adjusting the size and shape of the laser beam.

The wafer inspection apparatus according to the present invention can effectively clean the probe contact portion inside the apparatus by using a laser generating apparatus provided therein. In addition, unlike conventional cleaning techniques using cleaning pads, which are accompanied by heavy wear of the probe contacts, the wafer inspection equipment according to the present invention efficiently cleans the probe contacts without causing wear of the probe contacts using a laser beam, Can be removed. According to the present invention, the wafer inspection equipment including the laser cleaning function can drastically increase the life of the very expensive probe card (by about 80%), greatly reduce the inspection cost, and maintain the initial pointed probe shape for a long time , The initial high inspection yield is maintained for a long period of time, thus contributing to a high productivity.

FIG. 1 is a block diagram illustrating a wafer inspection apparatus including a laser beam cleaning function according to an embodiment of the present invention. Referring to FIG.
2 is a cross-sectional view for explaining a preferred embodiment of a probe cleaning unit including the laser beam generator of the wafer inspection equipment shown in FIG.
FIG. 3 is a perspective view showing the laser generator and the laser beam diaphragm shown in FIG. 2 together.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings and the description thereof are intended to aid those of ordinary skill in the art in understanding the present invention. Accordingly, the drawings and description are not to be construed as limiting the scope of the invention.

FIG. 1 is a block diagram illustrating a wafer inspection apparatus including a laser beam cleaning function according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 1, a wafer inspection equipment 1 according to an embodiment of the present invention includes a machine body 10 defining a wafer inspection chamber 11 in which a wafer W is inspected. The wafer inspecting apparatus 1 is configured such that the probe card C is introduced into the wafer inspecting chamber 11 through the upper portion of the apparatus main body 10. The probe card C has a plurality of probes P extending downward from the top of the wafer inspection chamber 11. [ The wafer inspection equipment 1 includes a moving unit for moving the wafer chuck 21 and the wafer chuck 21 three axes in the X, Y, and Z axes. The moving unit includes an XY moving stage 22 that operates to move the wafer chuck 21 in two directions in the X and Y axis directions and a XY moving stage 22 which moves the wafer chuck 21 on the XY moving stage 22 in the Z axis And a wafer chuck platform 23 that operates to raise or lower the wafer chuck platform 23 in the direction of the arrow. The wafer inspection apparatus 1 further includes a wafer cassette 30 disposed on one side of the apparatus main body 10 and a wafer W positioned on the wafer cassette 30 to be introduced into the apparatus main body 10 And loading means for loading into the wafer chuck 21. The loading means can be used by adopting a known one.

The wafer W fixed to the wafer chuck 21 in the wafer inspection chamber 11 in the apparatus main body 10 is brought into contact with the probe P and the tester T ) Sends various electrical signals to the element to grasp the electrical characteristics of the semiconductor element on the wafer W and determine whether the semiconductor element is good or not.

The apparatus for inspecting a wafer 1 according to an embodiment of the present invention includes a laser beam generator 40 for directly removing contaminants generated in the probe P from a laser beam in the apparatus main body 10 And is contained inside the apparatus main body 10. The laser beam generator 40 is fixed on the X-Y transfer stage 22 so as to be spaced apart from the wafer chuck 21. Accordingly, the installation position of the laser beam generator 40 is controlled by using the X-axis and Y-axis movement degrees of freedom of the XY transfer stage 22 for moving the wafer chuck 21 in the X- and Y- P to be irradiated with the laser beam, and more specifically, to the position facing the probe P. In this case,

The laser beam generator 40 is connected to the X-Y transfer stage 22 by a laser beam cleaning platform 41 and ascends and descends in the Z axis direction by the laser beam cleaning platform 41. The XY transfer stage 22 moves the laser beam generator 40 to a position facing the probe P directly under the probe P and then moves up and down the laser cleaning platform 41 The distance of the laser beam generator 40 with respect to the probe P is adjusted. The laser beam generator 40 is independently raised and lowered by placing the elevator bar 41 for laser cleaning independently of the wafer chaser elevator 23 in the present embodiment, It is also conceivable to extend the laser beam generator 40 and to install the laser beam generator 40 thereon.

Since the inner wafer inspection chamber 11 or the space of the apparatus main body 10 is narrow, the size of the laser beam generator 40 should be 300 mm or less in length and 200 mm or less in height. It is also preferable that the laser beam emitted from the laser beam generator 40 is emitted in the upward direction, not in the normal lateral direction. Also, it is preferable to use a collimated beam without focussing the laser beam irradiated to the probe P side by using a lens since the height control of the probe card P according to the height variation can be avoided.

In order to perform an effective laser cleaning, it is preferable to use a pulsed laser beam which is easy to control the cleaning process. The laser beam has a wavelength of 200 to 1500 nm, a peak output per pulse of 10 ⁶ W or more, The energy density is preferably 0.1 J / cm ² or more.

The wafer inspection equipment 1 according to the present embodiment supplies power to the laser beam generator 40 and controls the laser beam generator 40 so that the laser beam is effectively generated, And further includes a laser power supply device 42, a laser cooling device 43 and a laser control device 44 for managing the device 40. The laser power supply 42, the laser cooling device 43 and the laser control device 44 are connected to the equipment 10 in such a manner that the space inside the equipment body 10 where the actual wafer inspection and probe cleaning is performed can be saved to the maximum extent. It is preferable to position the wafer 10 on the outside of the wafer inspection chamber 11, and furthermore, on the outside of the wafer inspection chamber 11. A laser power supply line, a laser cooling line and a laser control line extending from each of the laser power supply device 42, the laser cooling device 43 and the laser control device 44 are connected to the outside of the apparatus main body 10 (10) and connected to the laser beam generator (40).

It is preferable to use a computer or a touch panel-based controller as the laser control device 44, and a cooling method using water (i.e., cooling water) is preferably used as the laser cooling device 43. When the laser control device 44, the laser power supply device 42 and the laser cooling device 43 are packaged in one package and attached to the side of the equipment body 10, the entire equipment space is minimized can do. The laser control device 44 is connected to the main controller device M for controlling the wafer inspection and is synchronously controlled to move the cleaning area of the probe P existing in various forms on the probe card C to the XY movement Various types of laser cleaning can be performed in cooperation with the moving unit including the stage 22 and the chuck platform 23.

FIG. 2 is a sectional view for explaining a preferred embodiment of a probe cleaning unit including the laser beam generator of the wafer inspection equipment shown in FIG. 1, and FIG. 3 is a cross-sectional view of the laser generator and the laser beam diaphragm shown in FIG. FIG.

2 and 3, a laser beam L for probe cleaning is emitted through an exit area on the upper side of the laser beam generator 40, where the exit area is a laser window with a laser beam transmittance of 99% window (400). The laser window 400 transmits at least 99% of the output of the laser beam emitted and physically completely blocks the emission area to physically seal the inside of the laser beam generator 40, And is prevented from entering the inside of the beam generator 40. This contributes to enhancing the reliability of the laser beam generator 40 by preventing many optical components in the laser beam generator 40 from being contaminated by external contaminants.

The wafer inspection apparatus according to the present embodiment further includes a laser beam diaphragm 60 as an element that participates in the laser cleaning of the probe P with the laser beam generator 40. The laser beam diaphragm 60 has a plurality of beam holes 61a, 61b, 61c and 61d having different sizes and / or shapes, and the plurality of beam holes 61a, 61b, 61c and 61d are used Thereby making laser beams of various sizes and shapes used for probe cleaning. The laser beam diaphragm 60 can be very useful when it is necessary to clean only a very small area.

61b, 61c, 61d of the laser beam diaphragm 60 having various sizes and shapes can be used to move the laser beam diaphragm 60 as required to form the intended beam hole 60a, 61a, 61b, 61c, 61d to the laser beam L, a laser beam of a desired size and shape can be generated and used automatically. During laser cleaning, contaminants are removed in the form of fine dust, which is very important.

To this end, the wafer inspection apparatus according to the present embodiment includes a dust collector 70, which is disposed adjacent to the cleaning area to remove 100% of dust generated during laser cleaning. At this time, the dust collecting device 70 should be located within 10 cm from the cleaning area so that effective dust can be collected.

As a result, the wafer inspection apparatus 1 according to the present invention includes a laser cleaning function in the apparatus main body 10, thereby selectively removing contaminants present in the probe contact portion without worn out of the probe, thereby effectively cleaning the probe It can be done very quickly.

It will be appreciated by those skilled in the art that changes may be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

10: equipment main body 21: wafer chuck
22: XY transfer stage 23: chuck elevator
40: laser beam generator 41: elevator bar for laser cleaning
42: laser power supply device 43: laser cooling device
44: laser control device 60: laser beam diaphragm

Claims (9)

1. A wafer inspection apparatus for inspecting a semiconductor wafer,
An apparatus main body for confining a wafer inspection chamber in which a probe is introduced at an upper portion to the inside;
A wafer chuck for holding the wafer in the apparatus main body;
A moving unit for moving the wafer chuck in the apparatus main body to selectively contact the probe and the wafer; And
And a laser generator for generating a laser beam in the main body of the apparatus and irradiating the probe with a laser beam,
Wherein the moving unit includes an XY moving stage for moving the wafer chuck in the X and Y axes and a wafer chuck lift which moves the wafer chuck in the Z axis direction on the XY moving stage, Wherein the beam generator is installed on the XY moving stage so as to be spaced apart from the wafer chuck and is moved in a direction facing up and down with the probe by the XY moving stage. delete The wafer inspection equipment according to claim 1, wherein the laser beam generator is vertically driven in the Z-axis direction by a laser cleaning platform operated independently of the wafer chasper. The apparatus of claim 1, wherein the laser beam generator irradiates the parallel beam type laser beam toward the probe. [6] The apparatus of claim 4, wherein a laser beam diaphragm having a plurality of laser beam apertures formed in at least one of a shape and a size is provided on the upper side of the laser beam generator, Wherein at least one of the size and the shape of the laser beam irradiated to the probe is adjusted. The apparatus according to claim 1, wherein a dust collecting device for collecting and permanently removing dust generated during laser cleaning of the probe is provided on the upper side of the laser beam generating stand. [2] The apparatus of claim 1, wherein the laser beam generating device has a laser window having a laser beam transmittance of 99% or more in a laser beam output area on an upper surface thereof. The laser beam generator according to claim 1, wherein a wavelength of the laser beam emitted from the laser beam generator is in a range of 200 to 1500 nm, a laser beam emitted from the laser beam generator is in the form of a pulse wave and the peak output of the pulse is 10 ⁶ W or more Wafer inspection equipment. The apparatus of claim 1, wherein the laser power supply device, the laser cooling device, and the laser control device for controlling the laser beam generator are located outside the apparatus main body.

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