JPH0414494B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a wafer processing apparatus, and particularly to a wafer processing apparatus that is capable of continuously performing double-sided scrub cleaning, double-sided water injection cleaning (jet cleaning), and spin drying of semiconductor wafers. The present invention relates to wafer processing equipment.

(b) Background of technology In the wafer process when manufacturing semiconductor devices, impurity introduction and vapor phase growth are used to remove contamination during transport and storage of the wafer to be processed and improve processing yield. , scrub cleaning, water injection cleaning,
A preprocessing treatment consisting of spin drying is performed.

(c) Prior art and problems Conventionally, the pretreatment process described above involves a dedicated scrub cleaning device, a device for jet cleaning and spin drying, and a process for transferring the wafer to be processed from the scrub cleaning device to a device for jet cleaning and spin drying. The line consisted of a conveying device consisting of a belt, etc.

In the conventional pretreatment process described above, the scrub cleaning device is schematically shown in plan views A and A-A in FIG.
As shown in the cross-sectional view B shown in arrow A, the wafer W to be processed is
A rotation axis Sm that applies rotational force m ₁ to
A pair of wafers W are pushed toward the center of the wafer W while the wafer W is supported and rotated by the pressure rollers C that position and horizontally support the wafer W. The wafer W was sandwiched between the rotating brushes B and both sides of the wafer W were scrubbed at the same time. In addition, the rotation axis Sm and the wafer W of the pressure welding roller C
The portion in contact with the side surface is formed into a V-shaped groove.

However, in the conventional scrub cleaning apparatus, since the parts of the rotation shaft Sm and the pressure rollers C that contact the wafer W are not constantly cleaned, contamination of the wafer to be processed from these parts is unavoidable. There was a problem.

In addition, in the equipment that performs water injection cleaning and spin drying, three positioning pins P ₁ , P ₂ , and P ₃ implanted on the rotating board are used as schematically shown in Fig. 2. The wafer W to be processed is clamped, and water injection cleaning and spin drying are performed while rotating the wafer W (m ₂ is an arrow indicating rotation), but in this case, the portion of the wafer W to be processed that contacts the positioning pins may not be sufficiently washed with water. Also, dirty washing due to delayed drying became a problem.

Furthermore, in the conventional pretreatment process, as mentioned above, it is necessary to transfer the wafer to be processed from the scrub cleaning equipment to the jet cleaning spin drying equipment.
At this time, the wet wafer to be processed is transported by a conveyor such as a belt, and during this time, foreign matter adhering to the belt, etc. and due to chemical reactions are removed from the surface of the wafer to be processed by jet cleaning. There was also the problem that more contaminants were deposited than could be removed.

Furthermore, in the conventional configuration, since the three types of devices mentioned above are used, there are also problems in that the equipment cost increases and the occupied area also increases.

(d) Purpose of the Invention The present invention improves the yield of the wafer process by eliminating contamination of the wafers to be processed during the pretreatment process, and prevents increase in equipment costs and expansion of the occupied area. This was done for the purpose of facilitating in-line processing, and this purpose is achieved by the wafer processing apparatus of the present invention having the following features.

(e) Structure of the Invention In other words, the present invention sandwiches a wafer to be processed between a pair of rotating brushes that rotate in the same direction and exert different rotational forces on the wafer to be processed, and further holds the wafer to be processed using a fluid jet type holding mechanism. A wafer processing method characterized by simultaneously scrubbing both sides of the wafer to be processed while rotating the wafer between the rotating brushes while holding the wafer to be processed; A first rotating brush that applies a predetermined rotational force and a cylindrical shape are arranged so that a wafer to be processed can be held therebetween, and
a second rotating brush that applies a rotational force different from that of the rotating brush; driving means for rotating the first and second rotating brushes in the same direction; and means for holding the wafer to be processed by jetting fluid; The present invention relates to a wafer processing apparatus used in the above-mentioned wafer processing method, characterized by comprising:

(f) Embodiments of the invention The present invention will be described below with reference to the drawings.

3 is a schematic top view A and a schematic perspective view B of an embodiment of a wafer processing apparatus according to the present invention, FIG. 4 is a functional explanatory diagram of a hollow support in the embodiment, and FIG. A to J are schematic process cross-sectional views showing the operation of the same embodiment.

The wafer processing apparatus of the present invention is formed, for example, as shown in FIGS. 3A and 3B. In the figure, W is the wafer to be processed, 1 is a container (cup), 2 is a drain port, 3 is a rotating board that has a hollow part and also functions as a passage for vacuum exhaust, air, and water, and 4 is also a rotating board. The shaft, 5 is a supply means for vacuum, air, water, etc., and 6 is a variable speed motor for driving the rotating substrate. and 7
Hollow columns a, 7b, and 7c are provided with vacuum, air, water, etc. through the rotating base plate on which the columns are installed, and function as vacuum chucks, air bearings, and water bearings. Also 8a, 8
b is a side roller, which touches the wafer W to be processed W floating from the hollow support from the side due to the effect of air or water bearing, and rolls the wafer W to be processed W by the effect of air or water bearings.
Specifies the top, bottom, left, and right positions of .

Note that a V-shaped groove is provided on the side surface of the roller to define the vertical position of the wafer to be processed.

9a and 9b are a pair of cleaning brushes that rotate in the same direction. This cleaning brush has the function of holding the wafer W to be processed from the x ₁ position, moving forward to the x ₂ position, rotating, and simultaneously scrubbing both sides of the wafer W while applying rotational force to the wafer W. The above-mentioned rotational force is the number of rotations of the cleaning brushes 9a and 9b,
This is achieved by changing the frictional force that each cleaning brush exerts on the wafer by changing the diameter, contact pressure on the wafer, etc. Here, in order to press and hold the wafer to be processed against the side rollers 8a and 8b, the frictional force of the cleaning brush 9b, which rotates in a direction that applies a frictional force in the pressing direction, must be made larger than that of the other cleaning brushes 9a. It is necessary to. In order to scrub the wafer sufficiently and to generate rotational force, it is effective to drive both brushes to rotate so as to scrub the wafer in opposite directions. Furthermore, in order to rotate the wafer, the line of action of the combined force of both frictional forces must be off the center of gravity of the wafer, so the length of the brush should be such that its tip is slightly away from the center point Ow of the wafer. It is chosen to reach a position exceeding x ₂ . Note that the cleaning brushes 9a and 9b may not be so-called brush-like but may be sponge-like. During this process, the wafer is held floating by water bearings, and the side rollers 8a,
8b and cleaning brushes 9a, 9b, there is no contact with solids. 10 is a motor for rotationally driving the cleaning brush, and 11 is a rotation transmission means. Further, 12a and 12b are injection means for spraying a cleaning liquid (usually pure water) onto both sides of the wafer W to be processed, m _R1 is an arrow indicating the rotation of the rotating substrate 3, and m _R2 is an arrow indicating the rotation of the wafer W to be processed. ms is an arrow mark indicating the forward direction of the rotating brushes 9a and 9b.

In the apparatus of the present invention, the center Ow of the wafer W to be processed is the center of rotation of the rotating substrate 3 as shown in the figure.
Another feature is that the rollers are shifted from Os in the direction in which the side rollers are disposed. Since the wafer W can be supported on the rotating substrate 3 by only the rollers 8a and 8b, jet cleaning and spin drying of the wafer W, which will be described later, can be effectively performed.

FIG. 4 shows a state in which, for example, a wafer W to be processed is being spin-dried.
c and 7a not shown, the rotation axis 4 of the rotating disk 3
Dry air or nitrogen introduced from the support is supplied and ejected from these supports to float the wafer W to be processed. At this time, since the center Ow of the wafer W to be processed is shifted from the center of rotation Os of the rotating disk 3 toward the side rollers 8b and 8a (not shown), the wafer W to be processed is mounted on the side rollers 8b and 8a (not shown). The rotating board is pressed against 8c (not shown), is supported in a state in which the left and right positions of the upper surface are determined by the V-shaped grooves of the rollers 8a, 8b, and is raised from the hollow supports 7b, 7c and 7a (not shown). 3, it rotates at high speed and the water adhering to the surface is scattered. Note that g in the figure is an arrow indicating the state of air ejection, and m _R1 is an arrow indicating the rotating state of the rotating board.

Next, regarding the operation of the wafer processing apparatus shown in the above embodiment, please refer to the schematic process cross-sectional diagrams shown in FIGS. and explain.

Refer to FIG. 5A. First, the cleaning brushes 9a and 9b are retracted, the hollow rotating substrate 3 is stopped, and the substrate W to be processed is evacuated as shown by the arrow V, and the hollow support 7b,
7c and 7a (not shown) are functioning as a vacuum chuck, the side rollers 8b and 8a (not shown) guide the sides of the hollow support 7b,
It is mounted and fixed on 7c and 7a (not shown).

See Figure 5B Next, cleaning brushes 9a and 9b (move simultaneously)
is in contact with both sides of the wafer W to be processed, and while sandwiching the wafer W, make sure that the tip is at the center of the wafer W to be processed.
Move the arrow forward to a position beyond Ow as shown in ms. (The wafer W to be processed is in a vacuum chuck state.) Refer to FIG. In a state where the wafer W to be processed is floated, cleaning brushes having different frictional forces against the wafer W are used in the same manner (arrows indicate the jetting state of pure water or air) as described above.
m _B1 and m _B2 ), and while the wafer W to be processed rotates on its own axis due to the difference in frictional force, both surfaces of the wafer W are scrubbed by the cleaning brushes 9a and 9b. At this time, both surfaces of the wafer W to be processed are sprayed with cleaning water (usually pure water) as shown by the arrow w _a . Note that this cleaning water may also be supplied from the shaft of the cleaning brush.

See Figure 5 D. Once the scrubbing is complete, the hollow support 7
After switching the vacuum chucks b, 7c and 7a (not shown) to hold the wafer W to be processed, the cleaning brushes 9a, 9b are returned to their original positions.

Refer to FIG. 5E. Next, while the wafer W to be processed is vacuum chucked, the rotating substrate 3 is started to rotate, and the rotational speed is gradually increased. m _R1 is an arrow indicating rotation.

Refer to Fig. 5. When the specified rotation speed is reached, the hollow supports 7b, 7
c and 7a (not shown) to the air or water bearing function.

In this state, the substrate W to be processed floats on the hollow column, is pressed against the side rollers 8b and 8a (not shown) by centrifugal force, and rotates together with the rotating substrate 3 while being supported by the side rollers. Next, in this state, pure water is sprayed onto both surfaces of the wafer W to be processed as indicated by the arrow w _a by a water injection means (not shown), thereby performing so-called jet cleaning of the wafer W.

Refer to Figure 5. After jet cleaning is completed, the hollow support 7
b, 7c and 7a (not shown) serve as an air bearing function, and the rotation speed of the rotating substrate 3 is further increased to a predetermined high speed, and the wafer W to be processed floats up from the hollow support, and the side rollers 8b and 8 (not shown)
The wafer W to be processed is spin-dried by being supported only by a and rotating at high speed together with the rotating substrate 3.

Refer to Figure 5 H. Once the above spin drying is completed, the hollow support 7
b, 7c and 7a (not shown) are switched to the vacuum chuck function, and the rotating substrate 3 is stopped with the wafer W to be processed fixed on the hollow support.

Although not shown hereinafter, the wafer to be processed is transferred to a processing device for the next process or a storage container by a transfer means.

(g) Effects of the Invention As explained above, the wafer processing apparatus of the above embodiment according to the present invention can perform scrub cleaning, jet cleaning, and spin drying in one apparatus without moving the wafer to be processed. can be performed consecutively. Therefore, according to the present invention, in the wafer process of semiconductor devices, the pretreatment process consisting of scrub cleaning, jet cleaning, and spin drying, which is performed immediately before wafer processing such as impurity introduction, vapor phase growth, and metal film formation, is performed in one step. Since the pretreatment process can be carried out using a single unit of equipment, the equipment cost is reduced and the area occupied is also reduced, making it extremely easy to inline the pretreatment process.

Furthermore, in the wafer processing method and apparatus according to the present invention, since the wafer to be processed is not moved between scrub cleaning, jet cleaning, and spin drying, contamination that conventionally occurs with transfer means such as belts can be avoided. In addition, as is clear from the description of the above embodiments, during scrub cleaning, jet cleaning, and spin drying, the wafer to be processed is supported at only two points by the side rollers, so contamination inside the apparatus is also prevented. Very few. Therefore, according to the present invention, contamination of the wafer to be processed during the pretreatment step is prevented, so that the yield of the wafer process is improved.

It should be noted that the wafer processing apparatus of the above embodiment can of course be applied to cases in which the steps of scrub cleaning, jet cleaning, and spin drying are carried out individually, and in cases in which the two steps are carried out consecutively.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional scrub cleaning device, FIG. 2 is a schematic diagram of a conventional jet cleaning and spin drying device, and FIG. 3 is a schematic top view of an embodiment of a wafer processing device according to the present invention. A, a perspective schematic side view B, and FIG. 4 are functional explanatory diagrams of the hollow support in the same embodiment, and FIGS. 5A to 5H are process sectional views showing the operation of the same embodiment. In the figure, 1 is a container (cup), 3 is a rotating board,
4 is a rotating shaft, 5 is a supply means for vacuum, air, water, etc., 6 is a variable speed motor, 7a, 7b, 7c are hollow columns, 8a, 8b are side rollers, 9a, 9b are cleaning brushes, 10 is a brush drive 11 is a rotation transmission means, 12a and 12b are water injection means, W is a wafer to be processed, m _R1 is an arrow indicating the rotation of the rotating substrate, m _R2 is an arrow indicating the rotation of the wafer to be processed,
ms is an arrow indicating the movement of the cleaning brush, Ow is the center of the wafer to be processed, Os is the rotation center of the rotating substrate,
x ₂ indicates the brush tip position when moving forward.

Claims (1)

[Scope of Claims] 1. A wafer to be processed is sandwiched between a pair of cylindrical brushes whose axes are substantially parallel to each other, and while the wafer is rotated by the frictional force applied from the brushes to the wafer, Both sides of the wafer are simultaneously scrubbed, and during the scrubbing process, the wafer is kept in a state where no solid body other than the brush comes into contact with the front and back surfaces of the wafer by means of a holding device that jets fluid and holds the plate-like object. The pair of brushes are rotated so that the frictional forces generated between the pair of brushes and the wafer are in opposite directions and have different absolute values, and after the scrubbing process is completed, the brushes are retracted. , holding the wafer by the holding device in a state where no solid objects come into contact with the front and back surfaces of the wafer, and rotating the wafer by a rotational drive device connected to the holding device; A wafer processing method characterized by blowing a fluid to wash away foreign matter attached to the surface or back surface. 2. A wafer scrubbing means, which is a pair of cylindrical brushes that scrub the front and back surfaces of the wafer to be processed, and rotates so that the friction forces generated between the brushes and the wafer are in opposite directions and have different absolute values. , wafer holding means for holding the wafer in a non-contact manner by ejecting fluid; and rotating the wafer held by the wafer holding means by a rotation drive device connected to the wafer holding means. means for blowing a fluid onto the rotating wafer to wash away foreign matter adhering to the surface or back surface of the wafer; and means for retracting the brush to a position where it does not interfere with the rotating operation. A wafer processing apparatus comprising: