JPH04186626A - Etching apparatus - Google Patents

Abstract

PURPOSE:To eliminate etching residue by always varying a contact surface of a wafer with a member for holding the wafer during processing, and to prevent generation of particles in a later step and diffusion of impurities into a semiconductor substrate by exposing the entire surface of a wafer with a spray nozzle upon rotation of a rotary shaft and a cam rotary shaft, and always holding the wafer by three chucking pawls. CONSTITUTION:In this etching apparatus, a wafer 21 is held by three chucking pawls. Then, a motor 12 is rotated to rotate a rotary shaft 1 and a cam rotary shaft 2. The position of a bracket 8 of the shaft 1 is varied to a cam 4 so that the pawls 3 are separated from the side of the wafer 21. A push rod 5 is moved in a central direction by the contour of a cam plate, the pawls 3 mounted on the other end are moved forward to push the wafer. As the shaft 1 rotates in this manner, the three pawls 3, always alternately hold the wafer 21. As a result, the wafer 21 is not disturbed in its visual field for spraying, and the wafer 21 can be entirely coated with processing solution uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an etching apparatus for etching a thin film of a wafer, which is a semiconductor substrate.

[Conventional technology]

FIG. 3 is a perspective view showing an example of a conventional etching apparatus. Conventionally, this etching apparatus, as shown in the same figure,
One chuck that holds the back and side surfaces of the wafer 22, a rotation mechanism that rotates the wafer 21 held by this chuck 19, and a front spray nozzle 20 and a back spray nozzle that spray processing liquid from the front and back surfaces of the wafer 21. 20a.

When etching a thin film on a wafer using this etching apparatus, first the wafer 19 on which the thin film has been formed is held by the chuck 22, and the wafer 19 is rotated, so that the front spray nozzle 20 and the back spray nozzle 21 are placed on the thin film surface. Etching was carried out by spraying a processing solution.

[Problem to be solved by the invention]

In the case of the conventional etching apparatus described above, the following problem occurs.

When attempting to etch a thin film by spraying from both the front and back surfaces of the wafer, etching remains are left in this area because the processing liquid cannot enter the contact surface between the wafer and the chuck. This etching residue peels off during wet processing and heat treatment in subsequent steps and becomes particles, causing a reduction in the yield of semiconductor devices. In particular, when impurities are introduced into a thin film on a semiconductor substrate, there is a drawback that the impurities diffuse into the wafer surface due to heat treatment in a post-process, changing the electrical characteristics of the semiconductor device.

An object of the present invention is to provide an etching apparatus that solves this problem.

[Means to solve the problem]

1. The first etching apparatus of the present invention has a spray nozzle placed on the front and back sides of the wafer and spraying a processing liquid onto the front and back surfaces of the wafer, and a bracket divided into six equal parts extending outward from the center at one end. a rotating shaft that is rotated at a predetermined rotational speed while being coaxial with the rotating shaft and rotating at a rotational speed that is different from the rotational speed of the rotating shaft;
a cam rotation shaft with a cam attached to its tip; a push rod that slides on the bracket in the radial direction of rotation and whose tip comes into contact with the outer surface of the cam; and a push rod with a cam attached to the other end of the push rod; A chuck claw that contacts and separates from the outer surface of the wafer, and as the rotation shaft and the cam rotation shaft rotate,
The entire surface of the wafer is exposed to the spray nozzle, and the wafer is always held by the three chuck claws.

2. The second etching device of the present invention comprises a drum-shaped rotating roller and a rotating roller attached to the tips of the opposing brackets, a pulley attached to the other end of the axis of the rotating roller, and a rotating shaft. A fixed shaft is provided at one end to which a fixed pulley is attached which wraps the wafer and rotates the pulley via a belt as the rotating shaft rotates, and the outer surface of the wafer is held between the front self-rotating roller and the rotating roller. It is characterized by

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIGS. 1(a) and 1(b) are a top view and a partial sectional view of an etching apparatus showing an embodiment of the present invention. As shown in FIGS. 1(a) and 1(b), this etching device is equipped with a bracket 8 at one end that is divided into six equal parts from the center and extends outward.
A rotating shaft 1 whose other end is rotated by a motor 12 via a pulley 11b and a belt 10b, a rotating shaft 1 that is fitted into the rotating shaft 4, and a cam 4 attached to one end, and whose other end is rotated by a motor 12 via a pulley 11a and a belt 10a. A cam rotating shaft 2 rotated by a motor 12, a chuck claw 3 that is fitted into a groove in a bracket 8, slides in the rotational radial direction and presses against the side surface of the wafer 21, and a tip is attached to the outer surface of the cam 4 by a spring 6. It is comprised of a push rod 5 that is in contact with a predetermined pressure and whose other end is attached to the chuck claw 3. Although not shown in this drawing, the wafer 2
Spray nozzles for spraying a treatment liquid on the front and back sides of 1 are arranged. Furthermore, there is a difference in rotational speed between the rotating shaft 1 and the cam rotating shaft, and a predetermined speed difference is created at the outer periphery.

Next, the operation of this etching apparatus will be explained.

First, each chuck jaw 3 is opened against the spring 6, and the wafer 21 is sandwiched between the three chuck jaws 3. This means that the remaining chuck jaws 3 must be attached to the cam 4.
This is because the push rod 5 is pushed and opened by the contour. Next, the motor 12 is rotated to rotate the rotating shaft 1 and the cam rotating shaft 2. As a result, the position of the bracket 8 of the rotary shaft 1 changes with respect to the cam 4 due to the difference in rotation speed. Due to this change, if the chuck jaw 3 was located away from the side of the wafer 21, the push rod 5 moves toward the center due to the contour of the cam plate, and the chuck jaw 3 attached to the other end moves forward to press the wafer. . As the rotating shaft 1 rotates, the three chuck claws 3 alternately sandwich and fix the wafer 21 at all times. Further, although an orientation flat 23 is formed on the wafer 21, this portion does not come into contact with the chuck jaws 3 because the central angle is smaller than 60°.

With this structure, there is no obstacle to the wafer 21's view of the spray, and the wafer 21 is
A uniform treatment liquid is applied to the entire surface of 3.

FIGS. 2(a) and 2(b) are a top view and a side view of an etching apparatus showing another embodiment of the present invention. , an autorotating roller 16 and a rotating roller 15 are provided facing the tip of a bracket 8a extending outward from a position dividing the center into six equal parts from one end of the rotating shaft 1a, and are connected to the rotating roller 15 via a belt 14. The fixed pulley 17 is connected to the fixed shaft 1
This is because it was installed at one end of 3. Other than that, this embodiment is almost the same as the previous embodiment.

In operation of this etching device, first, the rotating roller 16 is pulled in the radial direction. Although the bracket 8a to which the rotating roller 16 is attached is not shown in the drawing, it is made up of two overlapping plates, and one plate and the plate on the rotating shaft side are attached via a spring. This tensile force can widen the gap. When the wafer 21 is inserted between the expanded rotating roller 16 and the rotating roller 15 and the rotating roller 16 is released, the wafer 21 is sandwiched and fixed between the rotating roller 1 and the rotating roller 15. Next, the motor 12a is rotated, and the rotating shaft 1a is rotated by the pulley 11c and lld. As a result, the rotation roller 15 rotates due to the relative rotation difference between the rotation shaft 11 and the fixed shaft 12, and the contact surface between the wafer 21 and the rotation roller 15 changes every moment.

Further, since the rotating roller 16 is not connected to the fixed shaft 13, it can rotate freely, and this mechanism prevents the center of rotation from shifting and slipping when the wafer orientation flat 23 moves to the rotating roller 15. .

〔Effect of the invention〕

As explained above, in the etching apparatus of the present invention, by providing means for constantly changing the contact surface between the wafer and the member holding the wafer during processing, it is possible to expose the contact portion and the member to the spray nozzle. There is also an effect that there is no etching residue in the vicinity, and generation of particles due to peeling in a subsequent process and diffusion of impurities into the semiconductor substrate during heat treatment can be prevented.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are a top view and partial cross-sectional area of etching residue showing one embodiment of the present invention, and FIGS. 2(a) and (b) are
b) is a top view and a side view of an etching apparatus showing another embodiment of the present invention, and FIG. 3 is a perspective view of an etching apparatus showing a conventional example. 1.1a... Rotating shaft, 2... Cam rotating shaft, 3...
Tap claw, 4...Cam, 5...Push rod, 6
...Spring, 7...Sleeve, 8.8a...Bracket, 9...Groove, 10a, 10b, 10cm・1
4.-belt, lla, llb, 17.18=-pulley, 12.12a...motor, 13...fixed shaft, 1
5... Rotating roller, 16... Autorotating roller, 19...
・Chuck, 20...Surface spray nozzle, 20a・
...Backside spray nozzle, 21...Wafer, 22.
...missing number, 23...orientation flat.

Claims (1)

[Claims] 1. A spray nozzle is arranged on the front and back sides of the wafer and sprays a processing liquid onto the front and back surfaces of the wafer, and a bracket divided into six equal parts extending outward from the center is attached to one end, and a predetermined A rotating shaft that rotates at a rotational speed, a cam rotating shaft that is coaxial with the rotating shaft and rotates at a different rotational speed than the rotating shaft, and has a cam attached to its tip, and a cam rotating shaft that rotates on the bracket in a radial direction. a push rod that slides on the wafer and whose tip contacts the outer surface of the cam; and a chuck claw that is attached to the other end of the push rod and that contacts and separates from the outer surface of the wafer; An etching apparatus characterized in that the entire surface of the wafer is exposed to the spray nozzle as the rotation shaft and the cam rotation shaft rotate, and the wafer is always held by the three chuck claws. 2. A drum-shaped rotating roller and rotating roller attached to the tips of the opposing brackets, a pulley attached to the other end of the shaft of this rotating roller, and a belt that wraps around the rotating shaft and connects the pulley to one end. 2. The etching device according to claim 1, further comprising: a fixed shaft to which a fixed pulley is attached which rotates as the rotating shaft rotates; and the outer surface of the wafer is held between the rotating roller and the rotating roller. Device.