JP2007251019A - Etching apparatus of semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an etching method of a semiconductor wafer capable of being improved in its flatness and undulation and of making uniform an etching rate in a semiconductor wafer plane. <P>SOLUTION: An etching apparatus of a semiconductor wafer comprises a wafer magazine 3 which is rotated in an etching tank 2 into which an etching solution is supplied and on which many semiconductor wafers W are separated and mounted; and a cleaning solution ejection nozzle disposed just under the semiconductor wafer W with a spatulated cross sectional shape and with a flattened wide opening. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor wafer etching apparatus, and more particularly to a semiconductor wafer etching apparatus with an improved shape of an etching solution supply nozzle.

  In the manufacturing process of a silicon wafer, the silicon ingot is sliced into a silicon wafer, the silicon wafer is polished by chemical mechanical polishing, and etching is mainly performed to maintain a flat shape while removing the work-affected layer.

  In recent years, the flatness of silicon wafers has been improved by improving the processing accuracy in the lapping process, polishing process, etc. after the next process. Further, as the miniaturization of semiconductor devices progresses, the flatness becomes higher and the waviness is increased. Small silicon wafers are required.

  In the conventional silicon wafer etching apparatus, several tens of silicon wafers are mounted on a wafer magazine, and etching is performed while rotating the wafer in an etching tank filled with an etching solution.

  In such a conventional etching apparatus, the etching solution is supplied into the etching tank from the etching solution supply port provided below the wafer, and the overflow method is used to collect and circulate the etching solution overflowing from the upper opening of the etching tank. It is.

  For this reason, it is difficult to supply the etching solution between the wafers, and in order to supply the wafers between the wafers, it is necessary to rotate the wafers at a higher rotation speed. It has been difficult to control the flow rate of the etching solution in the process.

  Such a variation in the flow rate of the etching solution causes non-uniformity in the etching rate within the wafer surface, which causes uneven etching and waviness and deteriorates flatness.

  As a method for suppressing variations in the etching amount of silicon wafers, there is an etching apparatus in which adjacent wafers are rotated in different directions so that an etching solution flows in the space between the wafers as the wafers are rotated forward and reverse. It has been proposed (see, for example, Patent Document 1).

However, both the former method and the latter method of Patent Document 1 generate turbulent flow between the wafers and cannot improve the flatness and waviness.
JP 2002-231690 A

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a semiconductor wafer etching apparatus that can achieve a uniform etching rate in the surface of a semiconductor wafer and improve flatness and waviness. To do.

  In order to achieve the above-described object, a semiconductor wafer etching apparatus according to the present invention includes an etching tank to which an etching solution is supplied, a wafer magazine that is rotated in the etching tank and a plurality of semiconductor wafers are mounted separately. An etching solution jet nozzle is provided directly below the semiconductor wafer, and has an enlarged side cross-sectional shape and a flat and wide jet opening.

  According to the present invention, the etching rate in the semiconductor wafer surface can be made uniform, and the flatness and waviness can be improved.

  A semiconductor wafer etching apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a longitudinal sectional view of a semiconductor wafer etching apparatus, and FIG. 2 is a plan view of a nozzle assembly used in the etching apparatus.

  As shown in FIGS. 1 and 2, a semiconductor wafer etching apparatus 1 according to the present embodiment includes an etching tank 2 to which an etching solution is supplied, and a large number of semiconductor wafers (hereinafter simply referred to as “rotating semiconductor wafers”). Wafer magazine 3 on which W is spaced apart at a predetermined pitch, a rotation drive mechanism 4 comprising a motor 4a and a gear group 4b, and a nozzle disposed below wafer W. An assembly 5 is provided.

  The etching tank 2 is an overflow system in which the wafer magazine 3 is completely immersed in an etching solution, and the etching solution overflowing from the upper opening 2a is collected and circulated.

  The nozzle assembly 5 includes a number of nozzles 6 for ejecting an etchant, and the nozzle 6 has a rectangular plate-like outer shape having a length (width) substantially the same as the diameter of the wafer W, and is viewed from the side shown in FIG. An opening 6a for jetting an etching liquid having a flat and wide rectangular shape is formed, and the nozzle 6 is flat so as to be arranged immediately below the wafer W, that is, close to the lower side. A rectangular hollow nozzle assembly body 7 is erected in parallel with the wafer W at the same pitch.

  In the nozzle 6, the maximum opening 6 a 1 having the maximum area of the opening 6 a faces the gap between the semiconductor wafers W mounted on the wafer magazine 3 and is arranged close to the wafer W from below.

  The ratio of the maximum opening 6a1 of the opening 6a to the minimum opening 6a2 having the minimum area is preferably 1.5 or more. Thereby, the flow of the etching solution between the wafers becomes smooth, and the etching rate in the wafer surface is made uniform.

  Next, an etching method using the semiconductor wafer etching apparatus of this embodiment will be described.

  An etching apparatus 1 as shown in FIG. 1 is used to mount a plurality of wafers W on the wafer magazine 3 so as to be separated and rotated about the central axis. In this state, the wafer magazine 3 is immersed in an etching tank 2 filled with an etching solution. Thereafter, while rotating the plurality of semiconductor wafers W and the wafer magazine 3, the etching solution supplied via the etching solution introduction pipe 8 and the nozzle assembly body 7 is transferred between the nozzle 6 and the semiconductor wafer W to the full width of the wafer W. The semiconductor wafer W is etched.

  In the etching process as described above, the etching solution is disposed directly under the wafer W, and the etching solution is jetted from the opening 6a having the cross-sectional shape and the flat and wide rectangular shape of the nozzle 6, so that the etching solution is rectified. As a result, the wafer can be uniformly and uniformly supplied to the center of the wafer W, the global shape can be improved, and the etching solution can be supplied to the center of the wafer even when the wafer rotation speed is set large. Further, it is possible to improve the flow rate, and the flow rate can be easily controlled because the upward flow is forced by suppressing the influence of the flow caused by the rotation of the wafer for the rectification of the etching solution.

  According to the semiconductor wafer etching apparatus of this embodiment, the etching rate in the wafer surface can be made uniform, and the flatness and the swell can be improved.

"Example"
The wafer was etched using a semiconductor wafer etching apparatus as shown in FIG. 1, and the etching state of the wafer surface was examined.

Condition: Wafer: 200 mm silicon wafer used Wafer rotation speed: 60 rpm
Etching solution supply amount: 300 L / min
Result: As shown in FIG. 6, it was found that the etchant was rectified, reached the center of the silicon wafer, and was forcibly supplied uniformly.

"Comparative example"
A test similar to that of the example was performed using a punching metal instead of the nozzle of the etching apparatus in the example and setting the wafer rotation speed to 30 rpm.

  Result: At 60 rpm, the etching liquid was affected by the flow of the wafer due to the rotation of the wafer, and the liquid supply to the center of the wafer was stagnant, and the etching rate in the wafer surface could not be made uniform. As shown in the figure, since the uniform etching solution cannot be supplied even at 30 rpm, the in-plane waviness of the wafer is remarkably deteriorated.

1 is a longitudinal sectional view of a semiconductor wafer etching apparatus according to an embodiment of the present invention. The top view of the nozzle assembly used for the etching apparatus of the semiconductor wafer of this invention. The longitudinal cross-sectional view of the etching liquid injection nozzle used for the etching apparatus of the semiconductor wafer of this invention. The longitudinal cross-sectional view of the etching apparatus of the semiconductor wafer of the comparative example in an etching comparison test. The top view of the punching metal used for the etching apparatus of the semiconductor wafer of the comparative example of FIG. The figure which shows the result of an etching comparative test (Example). The figure which shows the result of an etching comparative test (comparative example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Etching apparatus 2 Etching tank 3 Wafer magazine 4 Rotation drive mechanism 5 Nozzle assembly 6 Cleaning liquid ejection nozzle 6a Opening part 6a1, 6a2 Opening 7 Nozzle assembly main body

Claims (2)

An etching tank to which an etching solution is supplied, a wafer magazine that is rotated in the etching tank and on which a large number of semiconductor wafers are spaced apart, and is arranged immediately below the semiconductor wafer, has a wide side cross-sectional shape and a flat width. An etching apparatus for a semiconductor wafer, comprising an etching solution jet nozzle having a jet opening formed therein. 2. The semiconductor wafer etching apparatus according to claim 1, wherein a ratio of a maximum opening area to a minimum opening area of the ejection opening is 1.5 or more.

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