JP2003017459A - Carrier cleaning method and apparatus - Google Patents

Abstract

(57) [Problem] To easily secure high-dimensional cleanliness required for a box-type carrier for a 300 mm wafer. SOLUTION: A cleaning liquid injection nozzle 21 atomizes a cleaning liquid into fine particles having a particle diameter of 50 μm or less and injects it at a high pressure onto at least the entire inner surface of a wafer carrier 10 which accommodates semiconductor wafers in parallel. The cleaning liquid spray nozzle 21 moves while facing the cleaning part and maintaining a substantially constant distance to the cleaning part. The wafer carrier 10 is supported with its opening downward so that the cleaning liquid sprayed on the inner surface of the carrier is sequentially discharged to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cleaning a wafer carrier in which semiconductor wafers are accommodated in parallel, and more particularly to a method and apparatus for cleaning a carrier suitable for cleaning the inner surface of a box type wafer carrier.

[0002]

2. Description of the Related Art In order to improve the productivity of silicon wafers, which are the material of semiconductor devices, the diameter of the wafers has been increased, and specifically the production technology of 300 mm wafers has been developed. It has been newly developed and its standardization is in progress.

The wafer carrier used for a 300 mm wafer is mainly a box type, unlike the conventional wafer carriers for 200 mm or less. That is, 200m
Wafer carriers used for wafers of m or less are mainly open rack models with bottoms, while 3
The wafer carrier used for a 00 mm wafer is mainly of a box type capable of hermetically sealing the inside.

This is because the degree of cleanliness required for a wafer becomes extremely high, and if it is attempted to improve the degree of cleanliness including a transfer line between processing steps, a high-performance clean room is required in a vast area, which is very large. However, if a box type wafer carrier is used, it is possible to reduce the cleanliness in a wide transfer area between the machines if the cleanliness inside the machines is improved. Is very large.

As a cleaning treatment for a wafer carrier, brushing in a cleaning liquid is effective for a conventional open rack type wafer carrier, and in particular, a combination of running water treatment by overflowing the cleaning liquid is combined. The treatment is said to be effective.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
For a box type wafer carrier used for mm wafers, brushing treatment in a cleaning solution is not sufficient, and an effective cleaning method has not been developed yet. The reasons why brush cleaning is not suitable for a box type wafer carrier are as follows.

In a box type wafer carrier,
Unlike the open rack type, the particles scraped out by brushing are discharged to the outside of the carrier.
So-called sweeping is structurally difficult, and it is not possible to expect a great effect even with running water washing by overflow that is combined with brushing processing, because the water permeability is poor.

Above all, with the miniaturization of the wiring structure, in the box type carrier for 300 mm wafers,
Although it is required to remove particles at the level of 0.1 μm, in the brushing cleaning, even if the flowing water treatment by overflow is combined, only particles at the level of 1 μm can be removed.

An object of the present invention is to provide a carrier cleaning method and device which can easily secure the high-dimensional cleanliness required for a box type carrier for 300 mm wafers.

[0010]

In order to achieve the above object, the present inventors have comparatively examined various cleaning methods. As a result, physical cleaning means is indispensable, but pure mechanical cleaning means such as brush cleaning is not enough. High effectiveness is high pressure jet cleaning, especially cleaning liquid with fine droplets. It was found that the high-pressure fine particle jet cleaning is performed by high-pressure jetting, and that the particle size greatly affects the particle removal performance in the high-pressure fine particle jet cleaning.

The present invention has been completed based on the above findings, and a carrier cleaning method for the same is that a cleaning liquid is finely divided into particles having a particle size of 50 μm or less on at least the entire inner surface of a wafer carrier in which semiconductor wafers are accommodated in parallel. It is a high-pressure jet.

Further, the carrier cleaning apparatus of the present invention comprises carrier supporting means for supporting a wafer carrier which accommodates semiconductor wafers arranged in parallel, and fine particles of the cleaning liquid on at least the entire inner surface of the wafer carrier supported by the supporting means. It is preferably provided with a cleaning liquid ejecting means for ejecting the fine particles having a particle diameter of 50 μm or less.

The wafer carrier is mainly a box type, but may be an open rack type. In the case of the box type, it is preferable to support the wafer carrier in a laterally downward direction so that the cleaning liquid sprayed on the inner surface of the carrier is sequentially discharged to the outside.

When the particle size of the cleaning liquid exceeds 50 μm, particles of 1 μm or less cannot be sufficiently removed.
The lower limit of the particle size is not specified because a smaller particle can remove smaller particles. A particularly preferable particle size is 10 μm or less.

The injection pressure of the cleaning liquid is preferably 3 to 50 MPa, particularly preferably 10 to 40 MPa. If this pressure is low, sufficient cleaning power cannot be obtained for the wafer carrier. If it is too large, the device becomes large in order to increase the pressure resistance. In addition, there is a risk of damaging the wafer carrier.

As a structure of the cleaning liquid ejecting means, it is preferable that the cleaning liquid ejecting nozzle faces the cleaning part of the wafer carrier, and the cleaning liquid ejecting nozzle is moved while keeping a constant distance from the cleaning part to the cleaning liquid ejecting nozzle. . It is also possible to move the wafer carrier instead of moving the cleaning liquid injection nozzle or together with the movement.

It is preferable to add a surfactant to the cleaning liquid. This is because the surfactant improves the wettability of the cleaning liquid with respect to the carrier surface and the adhered substance, and improves the cleaning effect. In particular, it is effective for removing particles at the level of 0.1 μm.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a carrier cleaning device showing an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of driving means in the carrier cleaning device.

The wafer carrier 10 comprises a plurality of 300 wafers.
It is a box type that accommodates mm silicon wafers aligned in the thickness direction. The carrier 10 includes a dome-shaped bottom plate portion 11 that is curved in a downward convex direction, and a bottom plate portion 11
Side wall portions 12, 12 extending upward from both side edge portions of the
And an end plate portion 13 that extends upward from both end portions of the bottom plate portion 11 in the wafer alignment direction and connects the side wall portions 12 on both sides,
A plurality of vertical grooves 14 into which the side edges of the wafer are fitted are provided on each inner surface of the side wall portions 12, 12.

In this embodiment, the wafer carrier 1 described above is used.
0 is supported in the cleaning tank 60 by the first driving means 40 in an inverted posture with the opening facing downward, and in this state, the entire inner surface is cleaned by the cleaning liquid ejecting means 20.

The cleaning liquid jetting means 20 is the second driving means 5
Cleaning liquid injection nozzle 21 and nozzle 21 attached to 0
Is equipped with a pump 22, which is connected via a flexible pipe, to the upstream side of the pump 22, and a cleaning liquid tank 24. The cleaning liquid is atomized from the nozzle 21 into particles having a particle size of 50 μm or less, and a high-pressure particle jet 30 is provided. Is injected at a pressure of 3 to 50 MPa.

The first drive means 40 has a chuck 41 for holding the wafer carrier 10 upside down, and a drive section 42 for linearly driving the chuck 41 in the XY directions.
The second drive means 50 includes a nozzle support portion 51 which is vertically inserted into the tank by penetrating the central portion of the bottom surface of the cleaning tank 60, and a first drive portion 52 which drives the nozzle support portion 51 to move straight in the Z direction.
And a second drive unit 53 that rotates the drive unit 52 in the θ direction around the Z axis, and the nozzle support unit 51 supports the cleaning liquid injection nozzle 21 at the upper end and It incorporates a third drive unit 54 for rotating 21 in the α direction around the horizontal axis.

First drive means 40 and second drive means 5
By the 5-axis (X, Y, Z, θ, α) drive by 0, the cleaning liquid injection nozzle 21 can be moved to any position inside the wafer carrier 10 and can be oriented in any direction.

In the cleaning process, the nozzle 21 jets the high-pressure fine particle jet 30 and moves inside the wafer carrier 10 in a plane perpendicular to the wafer alignment direction. More specifically, the nozzle 21 faces the carrier inner surface at a right angle, and moves on the path indicated by the arrow in FIG. 1 with the distance L from the nozzle 21 to the carrier inner surface kept constant.

That is, 1) Ascend along the vertical groove 14 from the position directly facing the opening edge of the one side wall 12. 2) Move along the inner radius of the bottom plate portion 11. 3) It descends to the opening edge along the vertical groove 14 of the other side wall 12. This is performed by a predetermined pitch in the wafer alignment direction (the alignment direction of the vertical grooves 14). The reverse movement may be combined every other time.

The movement pitch in the wafer alignment direction is
It is appropriately determined based on the relationship between the alignment pitch of the vertical grooves 14 on the wafer carrier 10 and the spread angle of the high-pressure fine particle jet 30 from the nozzle 21. The relationship between the two is shown in FIG.

The vertical groove 14 has an alignment pitch of 1 according to the SEMI standard.
It is 0 mm. If the movement pitch in the wafer alignment direction is 10 mm, the vertical grooves 14 can be cleaned exactly one by one, but the throughput is significantly reduced. The high pressure fine particle jet 30 jetted from the nozzle 21 is usually 45 to 9
Since there is a spread of about 0 degrees, the movement pitch may be set so as to wash the vertical grooves 14 in plurals, for example, 50 mm.
Even if they are moved one by one, the high-pressure fine particles 30 collide with both side surfaces of all the vertical grooves 14, so that high cleanliness can be obtained. Flute 1
If a plurality of nozzles 21 are arranged in the alignment direction of 4, the throughput is further improved.

By such high-pressure fine particle jet cleaning treatment, 0.1 μm from the entire inner surface of the wafer carrier 10 is obtained.
Level particles are also removed. That is, first, fine particles are removed by the high-pressure fine particle jet 30 in which the cleaning liquid is made into fine particles having a particle size of 50 μm or less. Second
In addition, since the nozzle 21 moves while facing the inner surface of the carrier at a right angle, a shadow (blind spot) is also generated in the vertical groove 14.
Does not occur. Thirdly, by moving the nozzle 21 in the direction of the vertical groove 14, a sweeping effect can be obtained. Fourth,
Since the wafer carrier 10 faces down, the cleaning liquid sprayed on the inner surface is efficiently discharged to the outside, and the sweeping effect is enhanced.

For the outer surface of the wafer carrier 10,
Since it is customary that the cleanliness of the inner surface is not required,
Ordinary jet cleaning or shower cleaning may be used, and the cleaning method is not particularly limited, but it is natural that cleaning with a high-pressure fine particle jet in which the cleaning liquid is made into fine particles having a particle size of 50 μm or less may be used, like the inner surface.

FIG. 3 is a schematic perspective view mainly showing the structure of a driving means of a carrier cleaning apparatus showing another embodiment of the present invention, and FIG. 4 is a schematic view showing a movement locus of a nozzle by the driving means.

The carrier cleaning apparatus of this embodiment is used for cleaning the open rack type wafer carrier 10. This wafer carrier 10 has side walls 1 on both sides.
2, 12 and end plate portions 13, 13 connecting the side wall portions 12, 12 on both sides, and the upper and lower surfaces are open.
The side walls 12 and 12 on both sides are displaced inward at the lower part for supporting the wafer, and a plurality of vertical grooves 14 into which both side edges of the wafer are fitted are provided on the inner surfaces of the side walls 12 and 12, respectively. Has been.

The wafer carrier 10 is placed on the support 61 in the cleaning tank 60 with the upper opening facing upward, and the upper end flange portion is fixed by the holders 62, 62 on both sides.

Cleaning liquid injection nozzle 2 of the cleaning liquid injection means 20
1 is supported from above by a driving means 70. The drive means 70 is connected to a first horizontal arm 71B that is vertically moved in the Z direction by a first motor 71A, and a tip portion of the first horizontal arm 71B, and is rotated around a vertical axis (in the θ1 direction by a second motor 72A). ) And a third horizontal arm 73B that is connected to the tip of the second horizontal arm 72B and is driven to rotate about the vertical axis (θ2 direction) by the third motor 73A. And the third
Connected to the tip of the horizontal arm 73B of the fourth motor 7
4A and a vertical nozzle support portion 75B that is rotationally driven about the vertical axis (θ3 direction). The nozzle support portion 75B supports the nozzle 21 at the lower end, and the nozzle 2
1 is driven to rotate about the horizontal axis (direction α) by the fifth motor 75A. Then, the first motor 71A and the second motor 72
The A and the third motor 73A position control the nozzle 21 in the XYZ directions, and the fourth motor 74B and the fifth motor 75.
A controls the attitude of the nozzle 21 itself.

According to the driving means 70, the nozzle 21
1 to 9 in FIG. 4 while facing the carrier surface at right angles and keeping the distance L to the carrier surface constant.
Move in the order shown in. That is, after moving from the lower end of the outer surface of one side wall 12 of the wafer carrier 10 to the upper end thereof, it moves from the upper end of the inner surface of the side wall 12 to the lower end thereof. Next, the other side wall portion 1 of the wafer carrier 10
After moving from the lower end to the upper end of the inner surface of 2, the side wall 12 moves from the upper end to the lower end of the outer surface.

By such movement of the nozzle 21, the side wall portions 12, 12 on both sides of the wafer carrier 10 are continuously cleaned by the high-pressure fine particle jet 30 in a predetermined region in the wafer alignment direction. By repeating this for every predetermined pitch in the wafer alignment direction, the side wall portions 12 on both sides,
The entire inner and outer surfaces of 12 are efficiently cleaned.

Needless to say, in this embodiment as well, the throughput can be further improved by arranging a plurality of cleaning liquid injection nozzles 21 in parallel in the wafer alignment direction.

[0037]

As described above, the carrier cleaning method and apparatus of the present invention uses the high-pressure fine particle jet cleaning in which the cleaning liquid is atomized and injected at high pressure. Satisfactory high-dimensional cleaning can be easily performed without using complicated and large-scale equipment even for a box type carrier for 300 mm wafers, which requires high cleanliness.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a carrier cleaning apparatus showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of drive means in the carrier cleaning apparatus.

FIG. 3 is a schematic perspective view mainly showing the configuration of drive means of a carrier cleaning apparatus showing another embodiment of the present invention.

FIG. 4 is a schematic diagram showing a movement trajectory of a nozzle by the driving means.

FIG. 5 is a plan view showing a relationship between an alignment pitch of vertical grooves in a wafer carrier and a spread angle of a high-pressure fine particle jet from a nozzle.

[Explanation of symbols]

10 Waha Carrier 20 Cleaning liquid jetting means 21 nozzles 30 High pressure particle jet 40, 50, 70 drive means 60 washing tank

Claims (7)

[Claims] 1. A carrier cleaning method characterized in that a cleaning liquid is atomized into particles having a particle size of 50 μm or less and is injected under high pressure onto at least the entire inner surface of a wafer carrier containing semiconductor wafers arranged in parallel. 2. The carrier cleaning method according to claim 1, wherein the cleaning liquid contains a surfactant. 3. The carrier cleaning method according to claim 1, wherein the spraying pressure of the cleaning liquid is 3 to 50 MPa. 4. The wafer carrier is a box type carrier,
The carrier cleaning method according to claim 1, 2 or 3, wherein the wafer carrier is supported laterally downward so that the cleaning liquid sprayed onto the inner surface of the carrier is sequentially discharged to the outside. 5. A carrier supporting means for supporting a wafer carrier for accommodating semiconductor wafers arranged in parallel, and a cleaning liquid ejecting means for atomizing and injecting the cleaning liquid onto at least the entire inner surface of the wafer carrier supported by the supporting means. A carrier cleaning device comprising: 6. A drive means for moving at least one of the wafer carrier and the cleaning liquid injection nozzle while directly facing the cleaning liquid injection nozzle to the cleaning part of the wafer carrier and keeping the distance from the cleaning part to the cleaning liquid injection nozzle substantially constant. The carrier cleaning device according to claim 5, further comprising: 7. The wafer carrier is a box type,
7. The carrier cleaning device according to claim 5, wherein the carrier support means supports the wafer carrier downward from the side.