KR100292613B1 - Wafer Clamping / Unclamping Device for Semiconductor Equipment - Google Patents

Abstract

SUMMARY OF THE INVENTION: The present invention provides a wafer clamping / unclamping apparatus of a semiconductor device that is improved so that a wafer does not stick together when a clamp finger is separated from a wafer.

Configuration: The present invention is to fix the main clamp finger on the upper end of the clamp shaft having a protrusion having a predetermined length at the top, and to install a sub clamp finger in a position associated with the protrusion of the clamp shaft in parallel with the main clamp finger And a push rod extending through a corresponding end of the main clamp finger to one side end of the sub clamp finger so that the sub clamp finger is delayed with respect to the main clamp finger in association with the lifting operation of the clamp shaft. Pressing and fixing the symmetrical positions of the wafer edges with the main clamp fingers and the sub-clamp fingers operated separately from each other, and when the main clamp fingers are separated from the wafer, the sub-clamp fingers are delayed for a predetermined time and then separated from the wafer. It works.

Effect: Due to the parallax interlocking between the main clamp finger and the sub clamp finger, the wafer remains on the upper surface of the substrate holder without any fine movement, thereby significantly reducing the damage of the wafer during the process.

Description

Wafer Clamping / Unclamping Device for Semiconductor Equipment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of wafer clamping / unclamping, which is essentially applied to semiconductor manufacturing facilities, and more particularly to a wafer clamping / unclamping apparatus of a semiconductor facility which does not cause wafer damage during the de-clamping process.

Most of the semiconductor manufacturing equipment is equipped with a clamping device for holding the wafer during processing, a typical equipment is a metal deposition equipment.

In general, wafer processing is performed through etching, which can be classified into dry etching and wet etching, and wet etching has recently been mainly used in dry etching due to the limitation of the density of isotropic etching in VLSI and ULSI devices. to be.

The dry etching technique is based on a method of chemically removing a workpiece by chemical reaction with active particulates (radicals) in a plasma state using a plasma, and a method of accelerating and physically removing ions physically and using these methods individually or in combination. Is applied.

In such a wafer processing process, one wafer is put into the process to be completed into a semiconductor device via about 300 manufacturing processes.

For example, in order to apply a silicon oxide film to a silicon substrate and selectively remove the oxide film, a photosensitive film is coated on the oxide film, and then exposed and etched through a mask to remove the exposed portion and expose the oxide film according to a chemical reaction. The exposed oxide film is formed in a desired pattern in a dry etching process.

In the semiconductor device obtained through the wafer processing as described above, a metal layer is deposited to facilitate the internal wiring and the connection function with the outside.

The metal layer is deposited according to a vacuum deposition technique, but in order for it to be in electrical contact with the semiconductor device with minimal resistance, a factory is needed to remove the naturally occurring oxide film on the surface of the wafer before deposition of the metal layer. The oxide film is removed from the wafer through high frequency etching in the sputtering process. At this time, the wafer is fixed with clamp fingers so that the wafer does not slip sideways or shake while sputtering on the horizontal module. The clamp finger is generally connected to and interlocked with a clamp shaft arranged to be able to move up and down around the servostraight holder. The clamp shaft is operated by a separate linkage, which is equipped with a spring on the outer circumference which always suppresses the clamp finger. 1 shows a conventional wafer clamping apparatus. 1, the clamp device 6 is erected at a peripheral symmetrical position of the substrate holder 4 on which the wafer 2 is placed on the upper surface, and the clamp device 6 is clamped on the upper end of the clamp device 6. The finger 8 is arranged to face the inside of the substrate holder 4 so as to press and secure the periphery of the wafer 2. The clamp finger 8 is also connected to a clamp shaft 10 extending through the interior of the clamp device 6, which is clamped upward by the elastic member 12 inside the clamp device 6. Of the wafer 2 on which the clamp finger 8 at its upper end is placed on the substrate holder 4 when the clamp shaft 10 is moved downward to resist the pressure of the elastic member 12. Press the upper surface to be fixed.

As described above, in the deposition process in which the wafer 2 is fixed to the upper surface of the substrate holder 4 with the clamp finger 8, the deposition of the metal film is performed over the entire upper surface of the wafer 2, so that the clamp finger 8 It is deposited to the same layer thickness up to and including the top surface.

At this time, the deposited metal film acts as a kind of binder between the wafer 2 and the clamp finger 8 so that the wafer 2 does not separate when the clamp finger 8 is raised by the clamp shaft 10. There is a problem of sticking phenomenon or dropping out during ascension, which often causes damage to the wafer.

Another example of clamping means for securing a wafer is known from US Pat. No. 5,733,426. The disclosed example includes a mechanism that is pivoted at an angle in the circumferential direction of the substrate holder when the clamp finger is away from the wafer. Therefore, the wafer does not stick to the clamp finger at the time of wafer separation. However, if the clamp finger is swiveled above the wafer, it will scratch the wafer surface even though it is a small area, and the circumferential force exerted on the wafer is strong enough to generate particles.

The present invention is a wafer clamping / unclamping device of a semiconductor device improved to prevent the wafer is stuck together when released from the clamp finger in order to solve the adhesion problem between the clamp finger and the wafer seen in the conventional wafer clamp device The purpose is to provide.

The apparatus of the present invention includes a clamp shaft which is lifted and operated by an external force and has a protrusion having a predetermined length at the top; A main clamp finger connected to the upper end of the clamp shaft and pressed against by a spring; A sub clamp finger having a push rod extending in parallel with the main clamp finger at a position associated with the protrusion and extending through a corresponding end of the mail clamp finger; A housing shielding the periphery of the main clamp finger and the sub clamp finger; A suspension pin disposed on an upper side of the housing to support the sub clamp finger; It is composed of a spring that is installed on the suspension pin and presses the sub clamp finger downward.

In such a configuration, the delay operation of the sub clamp finger with respect to the main clamp finger may be implemented by setting the length of the push rod to be longer than that of the protrusion.

Further, the means for penetrating the push rod of the sub clamp finger can be realized as a hole or a cutout hole provided in the tip of the main clamp finger.

In the present invention having the above-described configuration, both the main clamp finger and the sub clamp finger are operated in the vertical direction from above the wafer, and are not rotated in the circumferential direction.

In addition, since the lifting operation of these clamp fingers rises while breaking the metal thin film deposited on the outer surface of the main clamp finger while the wafer is held by the sub clamp finger, the wafer will not stick to the next time the sub clamp finger is raised. Will not.

1 is a side view showing the configuration of a conventional wafer clamping / unclamping apparatus.

Fig. 2 is a sectional side view of an essential part showing the construction of a wafer clamping / unclamping apparatus according to the present invention;

3 is a side cross-sectional view of the state in which the wafer is clamped by the apparatus depicted in FIG.

4 is a cross-sectional side view illustrating the process of unclamping a wafer by the apparatus depicted in FIG.

＊ Description of symbols for main parts of the drawings ＊

20: substrate holder 22: clamp housing

24: clamp shaft 26: spring

28: projection 30: main clamp finger

30a: Tip portion of main clamp finger 30b: hole or cutout hole

32: sub clamp finger 32a: end portion of the sub clamp finger

32b: Push Rod 34: Housing

36: suspension pin 38: bullet spring

Preferred embodiments of the present invention described above will be described in detail with reference to FIGS. 2 and 3 as follows.

In FIG. 2 the clamp housing 22 is erected vertically at a position symmetrical around the substrate holder 20. In the inner center of this clamp housing 22, the clamp shaft 24 is arrange | positioned so that a lifting / lowering is possible in the axial direction. A spring 26 is provided on the outer circumference of the clamp shaft 24, and a protruding portion 28 of a predetermined length is provided on the upper end, and the main clamp finger 30 is fixedly installed.

One end 30a of the main clamp finger 30 extends to the periphery of the substrate holder 20. The protrusions 28 may be provided at predetermined positions on the upper surface of the main clamp finger 30 or may be formed at two positions together with the uppermost ends of the clamp shafts 24.

Along with the main clamp finger 30, a sub clamp finger 32 is arranged in parallel thereon. The periphery of the main clamp finger 30 and the sub clamp finger 32 is surrounded by a housing 34, and a pair of suspension pins 36 mounted on the ceiling inside the housing 34 are the sub clamp fingers. Suspend (32) in a balanced manner.

The pair of suspension pins 36 are also provided with an elastic spring 38 to press the sub clamp finger 32 downward.

In addition, the push rod 32b is vertically disposed at one side end 32a of the sub clamp finger 32 to penetrate one side end 30a of the main clamp finger 30.

have. In addition, one side end portion 30a of the main clamp finger 30 is provided with a hole or cutout hole 30b for allowing the extension of the push rod 32b.

The push rod 32b is set longer than the length of the protrusion 28 formed at the upper end of the clamp shaft 24 so that the protrusion 28 is connected to the sub clamp finger 32 when the clamp shaft 24 is operated in the upward movement. The time for contact and interference can be delayed slightly.

The suspension pin 36 has a stopper 36a formed at the end of the suspension pin 36, and the stopper 36a is used to limit the downward position of the sub clamp finger 32 to a predetermined range.

The operation of the clamping / unclamping device configured as described above is as follows.

The main clamp fingers 30 and the sub clamp fingers 32 which are operated independently of each other are interlocked by the clamp shaft 24 and the spring spring 38, respectively, and are lowered in the same direction to be placed on the substrate holder 20. Press the edge of) to fix it.

The wafer 39 is carried on the arm of a wafer transfer robot (not shown). After the wafer 39 is thus fixed, the periphery of the sub-straight holder 20 is evacuated, and then the wafer 39 Deposition processing takes place.

The metal thin film 39a by the deposition covers the surface of the wafer 39 as well as the front end portion 30a of the main clamp finger 30 so that the wafer 39 and the main clamp finger 30 are in a sticking state. They stick together until they are separated.

Separation of the deposited wafer 39 is performed by the clamp shaft 24 being moved up by the elastic force of the spring 26. When the clamp shaft 24 is raised, as shown in FIG. 4, the main clamp finger 30 fixed at the top thereof is detached from the wafer 39, but the protrusion 28 of the clamp shaft 24 is sub-clamped. The push rod 32b of the sub clamp finger 32 alone presses and fixes the wafer 39 until it contacts and interlocks with the finger 32. As a result, the romaine clamp finger 30 is safely removed from the wafer 39. Next, when the protrusion 28 of the clamp shaft 24 pushes up the sub clamp finger 32, the sub pin finger is lifted from the wafer 39 by being interlocked with the suspension pin 36 while being raised and interlocked. The push rod 32b of 32 comes off.

As a result, the wafer 39 is left unmoved at all on the upper surface of the substrate holder 20, and then waits until it is taken out by the arm of the wafer transfer robot (not shown).

On the other hand, since the periphery of the push rod 32b is protected by being inserted into the hole of the main clamp finger 30 or the cutout hole 30b, no metal is deposited on the portion thereof, and thus, the push rod 32b may be lightly separated from the wafer 39.

The deposited wafer 39 is taken out, and once the new wafer 39 is conveyed to the upper surface of the substrate holder 20, the clamp shaft 24 is inverted to the downward movement again to repeat the operation of clamping / unclamping the wafer. Done.

As described above, according to the present invention, in clamping and unclamping a wafer to a top surface of a substrate holder with a clamp finger in a semiconductor manufacturing facility, the clamp finger is composed of a main clamp finger and a sub clamp finger which are operated independently of each other, The delayed operation causes the clamp finger to fall off the wafer without shaking, thereby fundamentally solving the problems seen in the conventional clamping device, thereby having the effect of processing without damaging the wafer.

In addition, the device of the present invention has the advantage that the structure is not complicated and can be added to the existing equipment without any difficulty, and the structure of the device forms a parallax interlocking relationship there is no fear of malfunction or failure.

Claims (6)

A clamping / unclamping apparatus for securing a wafer in a semiconductor manufacturing process, comprising: a housing; A suspension pin disposed protruding from an inner upper side of the housing, the suspension pin having a stopper having a different diameter at an end thereof; An elastic spring disposed on the suspension pin; A sub-clamp finger having one end of which is disposed on the suspension pin together with the elastic spring and pressed downward to move upward and downward; A clamp shaft which is lifted and operated by an external force; One end of which is coupled to an upper end of the clamp shaft and is clamped upward by a spring; And a protrusion protruding to a predetermined length at an upper end of the coupling portion of the clamp shaft and the main clamp finger, wherein the wafer is fixed by the main clamp finger and the push rod while the clamp shaft moves downward when clamping. In the case of unclamping, the clamp shaft is moved upward and the main clamp finger is first separated from the wafer, and when the protrusion contacts the sub clamp finger, the push rod is separated from the wafer. Device. The wafer clamping / unclamping device according to claim 1, wherein the suspension pins are disposed perpendicular to the inner ceiling of the housing and have at least one pair arranged therein. The wafer clamping / unclamping apparatus of claim 1, wherein the push rod of the sub clamp finger is set to be longer than the length of the protrusion of the clamp shaft. The wafer clamping / unclamping device of claim 1, wherein a hole or a cutout hole through which the push rod of the sub-clamp finger extends is provided at a distal end of the main clamp ping a. The wafer clamping / unclamping apparatus of claim 1, wherein the protrusion has a configuration provided on an upper surface of the main clamp finger. 6. The wafer clamping / unclamping device according to claim 1 or 5, wherein the protrusion is formed integrally with the clamp shaft or the main clamp finger.