JP2555034B2 - Processing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a processing apparatus, and more particularly to a processing technique effectively used for cleaning and drying a semiconductor thin plate in manufacturing a semiconductor device.

[Conventional technology]

Generally, when manufacturing semiconductor devices such as IC and LSI,
Wet chemical cleaning treatment is often used. For example, when diffusing impurities into a semiconductor thin plate (hereinafter, also simply referred to as a wafer), the surface of the wafer is etched before the diffusion process, and then the wafer is cleaned and dried. As a cleaning and drying method, there is a method of washing the wafer with water and then rotating the wafer to dry it, or a clean drying by steam.

 The present invention belongs to the former washing and drying.

2. Description of the Related Art Conventionally, wafers are cleaned by washing with water and drying in various forms. Basically, after etching a wafer, a tank filled with clean water is put in and washed with water. In this case, a plurality of wafers are accommodated in a jig called a cartridge and washed. The cartinge is immersed in pure water for a certain period of time, and the wafer surface is washed by substituting the pure water on the wafer surface. After washing with water, the cartridge is taken out of the washing tank and is attached to a centrifugal dehydrator called a spin dryer and is spin dried. This rotation drying is the mainstream of wafer drying.

For example, regarding such rotary drying technology, "Electronic Materials", March 1983, published by the Industrial Research Group, March 1, 1983
Issued on pages 68-71 and 124. The technique described below is disclosed in this document. That is, the entire wafer cassette (cartridge) on which 25 wafers are printed is washed. After that, the wafer cassette is set in a centrifugal dehydrator called a spin dryer, the wafer cassette is rotated at high speed, and the washing water and the like adhering to each wafer in the wafer cassette is spun by centrifugal force, causing the water to run out of the wafer. Done. Further, as described in the same document, various measures for preventing foreign matter adhesion are taken.

[Problems to be solved by the invention]

As described above, the wafer is cleaned in the photolithography process when the diffusion process or the like is performed.

By the way, when the degree of integration progresses from 1 Mbit to 4 Mbit, and further to 16 Mbit as in a memory LSI, it becomes necessary to miniaturize the element package size from 1 micron size to submicron size. With this submicron rule, even the size of the foreign matter adhering to the wafer is considered to be a problem. In other words, with the submicron rule, the size of foreign matter that directly leads to defects is 0.1 μm.
The following is a problem.

When the present spin dryer is evaluated in terms of cleanliness and performance on the premise of these things, (1) dust is generated in the rotating mechanism, and (2) it is generated by an impeller effect generated when the wafer cassette is rotated. According to the present inventor, there are problems such as inclusion of foreign matter from the outside due to reduction of negative pressure in the drying chamber due to the rotating flow, and (3) reattachment of foreign matter to the main surface of the wafer due to stirring of foreign matter present in the drying chamber. I was revealed.

An object of the present invention is to provide a processing device in which foreign matter is unlikely to adhere when dried.

The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[Means for solving problems]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows.

That is, the processing apparatus of the present invention has a structure in which a clean gas is forcibly blown from the upper and lower portions of a spin chuck on which a wafer to be processed is placed and rotated. Further, on the upper surface and the lower surface of the spin chuck, proximity plates are provided at positions where the cleaning water scattered by the centrifugal force does not reach and is not reflected and which makes the gas flow rate flowing in the radial direction uniform. Further, an exhaust mechanism for forced exhaust is provided at the periphery of the processing chamber constituted by a pair of proximity plates. The exhaust mechanism exhausts the gas in the processing chamber by an ejector action.

[Action]

According to the above means, the cleaning water scattered by the centrifugal force is not reflected by the proximity plate and adheres to the wafer surface, and clean gas is supplied to the center of the upper surface and the lower surface of the spin chuck. Since the gas flows uniformly by the proximity plate and is forcedly exhausted by the ejector action, the gas flow becomes a laminar flow and flows in the processing chamber in the radial direction without stagnation, so that the drying without adhering foreign matter can be achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a main part of a drying device according to an embodiment of the present invention. In this embodiment, an example of rotating and drying a wafer cleaned by a wet chemical will be described.

As shown in FIG. 1, the drying device has a spin chuck 2 on the main surface (upper surface) of which a wafer 1 to be processed is placed. The spin chuck 2 holds the wafer 1 by vacuum suction. The spin chuck 2 is attached to the tip of a rotary shaft 4 rotated by a spin motor 3. Therefore, the spin chuck 2 is rotated at a desired rotation speed by driving the spin motor 3.

On the other hand, above and below the spin chuck 2,
A donut plate-shaped proximity plate 5 is arranged in each case. These proximity plates 5 are cleaning water scattered from the surface of the wafer 1 by a centrifugal force and a rotating air flow based on the rotation of the wafer 1,
More specifically, it is arranged at a position that is out of the region where the cleaning water particles are directly scattered and that is closest to the wafer 1. The proximity plate 5 has a parabolic surface so that the airflow flowing in the processing chamber 6 becomes a laminar flow. That is, the dispersion holes 7, 8 in the center of the proximity plate 5
Clean air 9 that is forcibly sent to the processing chamber 6 from the
However, when flowing from the center of the proximity plate 5 toward the peripheral edge of the proximity plate 5, it is considered that the airflow flowing between the wafer 1 and the proximity plate 5 becomes a laminar flow. Therefore, the proximity plate 5 has a structure in which the space height of the processing chamber 6 is wide at the center of the processing chamber 6 and the space height is low at the peripheral edge. Further, in this structure, the cross-sectional area of the flow passage is constant at each part, and the gas flow passage is constant.

Further, the cleaning water adhering to the wafer 1 is scattered from the peripheral edge of the wafer 1 to the surroundings by a centrifugal force. At this time, it has been clarified by an experiment that the scattered cleaning water particles have an angle and are obliquely upward. Scatter on. Therefore, the proximity plate 5
The inner surface around the is formed so as to have a desired angle θ. This θ is, for example, around 6 °. As a result,
The cleaning water scattered from the edge of the wafer 1 does not come into contact with the periphery of the proximity plate 5 and does not return to the inside of the processing chamber 6 due to reflection.

For these reasons, the gas flow on the front and back surfaces of the wafer 1 in the processing chamber 6 flows in a laminar flow without stagnation and is exhausted.

In addition, as described above, clean gas, that is, clean air 9 is provided in the central portions of the pair of proximity plates 5, respectively.
Dispersion holes 7 and 8 for dispersively supplying are provided. The dispersion holes 7 and 8 are adapted to supply the clean air 9 indicated by the arrows from the clean air supply units 10 and 11 through the clean air supply pipes 12 and 13. Since the rotary shaft 4 of the spin motor 3 penetrates the clean air supply pipe 13, a seal 14 is attached to the rotary shaft 4 to prevent the clean air 9 from leaking from the clean air supply pipe 13. Further, since the clean air 9 is forcibly supplied into the processing chamber 6 by the gas supply mechanism, the central portion of the processing chamber 6 does not become negative pressure even when the spin chuck 2 rotates, but becomes positive pressure,
Care is taken to prevent the washing water particles blown away by centrifugal force from returning.

On the other hand, on the periphery of the processing chamber 6, that is, on the periphery of the pair of proximity plates 5, a ring-shaped bounce prevention cylinder 15 extending along the periphery is provided. An exhaust pipe 17 connected to the exhaust unit 16 is connected to the bounce prevention cylinder 15 in a communicating state. Further, an intake hole 18 is provided in each portion of the anti-rebound cylinder 15 opposite to the communicating portion with the exhaust pipe 17. The exhaust mechanism is composed of the exhaust unit 16, the bounce prevention cylinder 15, the exhaust pipe 17, and the intake hole 18, and exhausts air 19 while sucking the air 19 from the intake hole 18. As a result, due to the exhaust operation of the exhaust unit 16, the air 19 sucked from the intake hole 18 is exhausted through the exhaust pipe 17, and the exhaust mechanism itself constitutes the exhaust flow, so that the process chamber 6 is ejected by the eject action. The gas containing the cleaning water particles is sucked out and forced exhaust is performed.

In addition, with respect to the opening interval at the peripheral edge of the processing chamber 6, that is, the gap interval (gap) formed by the pair of proximity plates 5 and continuous with the anti-rebound cylinder 15, the anti-rebound cylinder.
The interval between the communicating portions of the exhaust pipe 17 and the exhaust pipe 17 is significantly widened so that the washing water particles and the like once entering the bounce prevention cylinder 15 will not return to the inside of the processing chamber 6. The air 19 sucked from the intake hole 18 also acts as a preventive agent for preventing the washing water particles from returning to the processing chamber 6. That is, the intake hole 18
Are arranged in the bounce prevention cylinder 15 at equal intervals and
The forced exhaust of 16 guides the air 19 into the apparatus in synchronization with the exhaust from the processing chamber 6, so that the exhaust amount balance is kept constant. In addition, because of the existence of the intake holes 18,
Since the air 19 flowing from 18 flows toward the exhaust portion 16, the gas in the processing chamber 6 is sucked into the rebound preventing cylinder 15 by the gas suction effect, that is, the eject effect. Therefore, the back-flow phenomenon of the cleaning water particles in the bounce prevention cylinder 15 into the processing chamber 6 is less likely to occur, and the re-adhesion of the scattered cleaning water particles to the wafer 1 does not occur.

Further, although not shown, the entire apparatus is controlled by a control system. That is, based on the processing condition setting information input to the control system, the rotation speed of the spin chuck 2, the processing time, the supply amount of the clean air 9, the exhaust unit 16
The engine displacement and other parameters are automatically controlled. Similarly, a series of sequence operations are automatically controlled by this control system.

Next, the rotation drying of the wafer according to the present invention will be described.

First, various conditions such as the clean air supply amount, the exhaust amount, the rotation speed of the spin motor, and the processing time are input to the control system.

Next, the chemically wet-cleaned wafer 1 is loaded on the spin chuck 2 by a handler (not shown). The wafer 1 is held on the spin chuck 2 by vacuum suction.

Next, the spin chuck 2 is rotated by a predetermined rotation sequence, and the wafer 1 is dried. At the time of this drying, the clean air 9 is forcibly supplied from the upper and lower portions of the processing chamber 6 and is forcibly exhausted by the exhaust unit 16. At this time, the clean air 9 flowing on the main surface of the wafer 1 flows as a laminar flow along the main surface of the wafer 1 and enters the bounce prevention cylinder 15. Further, the cleaning water particles scattered by the centrifugal force from the main surface of the wafer 1 ride on the flow of the clean air 9 while entering the rebound preventing cylinder 15 and do not adhere to the main surface of the wafer 1 again. Further, since the cleaning water particles scattered from the wafer 1 do not reach the proximity plate 5, there is no reflection of the cleaning water particles on the proximity plate 5 and reattachment of foreign matter to the wafer 1 due to the reflection does not occur. Further, the exhaust gas 20 such as cleaning water particles that has entered the bounce prevention cylinder 15 does not return to the inside of the processing chamber 6 again due to the forced exhaust of the exhaust system or the ejector effect, and the foreign substances can be prevented from adhering to the wafer 1. .

After the drying operation, the spin chuck 2 stops rotating and the handler unloads the wafer 1 on the spin chuck 2 to a predetermined portion.

According to such an embodiment, the following effects can be obtained.

(1) According to the present invention, in the processing space on the main surface side and the back surface side of the wafer that is the object to be processed, the gas is exhausted as a laminar flow, so that the foreign matter fills the processing chamber by stirring the air flow. In this case, it is possible to obtain the effect that it is possible to achieve the drying in which the foreign matter hardly adheres to the wafer.

(2) According to the present invention, since the communication gap between the bounce prevention cylinder and the exhaust pipe is wider than the communication gap between the processing chamber and the bounce prevention cylinder, the air is exhausted from the processing chamber into the bounce prevention cylinder. Since it is difficult for the cleaning water particles to return to the processing chamber, it is possible to obtain the effect that the drying can be achieved without causing foreign matter to adhere to the wafer.

(3) According to the present invention, the exhaust system on the side of the bounce prevention cylinder has a structure in which the air outside the apparatus is sucked through the intake hole provided in the bounce prevention cylinder and this intake air is also exhausted. This air flow also has the effect of sucking out the gas in the processing chamber, enabling efficient exhaust and preventing the exhaust gas from returning from the bounce prevention cylinder to the processing chamber. Therefore, it is possible to obtain the effect that the drying can be achieved without causing foreign matter to adhere to the wafer.

(4) Due to the above (1) to (3), according to the present invention, it is possible to realize clean drying in which foreign matter is unlikely to adhere, so that it is possible to achieve an effect of reducing appearance defects due to foreign matter.

(5) Due to the above (4), according to the present invention, it is possible to obtain the effect that the improvement of the yield can be achieved due to the reduction of foreign matter adhesion.

(6) According to the above (4), according to the present invention, it is possible to design a sub-micron rule pattern from the reduction of foreign matter adhesion, and it is possible to obtain the effect that the degree of integration of semiconductor devices can be improved.

(7) According to the following (1) to (6), according to the present invention, since cleaning and drying are possible, a synergistic effect that a product of excellent quality can be manufactured at low cost is obtained.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned embodiments and can be variously modified without departing from the scope of the invention. For example, the wafer is rotated by rotating the wafer while applying ultrasonic vibration to the spin chuck to clean the wafer by supplying the cleaning liquid filtered between the pair of proximity plates, and then the supply of the cleaning liquid is stopped and Cleaning and drying can also be achieved by rotating the to dry. In this embodiment, not only simple drying but also cleaning before drying is possible.

Further, an example in which the wafer is dried while being heated in order to increase the drying speed and prevent the generation of watermarks and the like can be considered. For example, FIG. 2 shows an example of a processing apparatus in which a microwave irradiation apparatus is arranged to heat a wafer.

In this apparatus, a wafer 1 which is an object to be processed is provided with three top chucks 2 provided at 120 ° intervals so that one can be opened and closed.
Chucked by 1. On the other hand, the three piece chucks 21 are attached to the lower proximity plate 5. The lower proximity plate 5 is rotated by a rotation drive unit (not shown). On the other hand, from the unillustrated cleaning water supply unit and replacement gas supply unit, clean cleaning water 22 as shown by the solid line and clean replacement gas 23 as shown by the broken line
However, when the valves are switched, the dispersion holes 7, 7
It is structured so that it is supplied evenly from 8. The inner surface shape of the upper and lower proximity plates 5 facing the wafer 1 is a shape in which the replacement gas 23 and the replacement gas 23 act on the wafer 1 at a constant speed, as in the above embodiment. Also, a pair of proximity plates 5
Is installed in a metal cavity 24 that can contain microwaves, and the wafer 1 is irradiated with a predetermined amount of microwaves 26 generated from the microwave generation unit 25. Therefore, as the microwave 26 is transmitted, the proximity plate 5, the top chuck 21 and the like are made of a material through which microwaves are transmitted,
The parable is made of ethylene tetrafluoride resin.

In these examples, although not particularly described,
In order to process the wafer 1 with high accuracy, it is possible to measure the temperature of the wafer 1 and feedback-control the amount of microwave output from the microwave generator 25. Further, in the exhaust / drainage system, the intake hole 18 may be provided in a predetermined portion of the cavity 24, and the exhaust / drain by the exhaust / drain section 27 may be ensured by the eject action as in the above-described embodiment.

In this embodiment, the cleaning water with high cleanliness is applied to the wafer 1.
Irradiate microwave 26, which is an electromagnetic wave, while supplying 22
Rotation cleaning and bar-per-rise rotation drying are performed for a predetermined time,
After that, the supply of the cleaning water 22 is stopped. Then, while supplying a highly clean replacement gas 23 into the processing chamber 6, the wafer 1 is instantaneously subjected to rotary drying by microwave heating. With this device, due to the synergistic effect of the foreign matter adhesion reduction effect due to rebound, the bar-parize effect, and the uniform high-speed drying effect,
The wafer 1 can be cleanly washed and dried.

In the above description, the case where the invention made by the present inventor is mainly applied to the wafer drying technology which is the field of application which is the background has been described, but the invention is not limited thereto, and for example, glass for photomasks or the like. Board,
It can also be applied to the drying technology for metal plates. Also, the present invention
In addition to the semiconductor industry, it can be applied to various washing and drying technologies in the photographic industry, printing industry, precision machinery industry, chemical industry, etc.

 The present invention is applicable at least to the drying technique.

[Drying of the Invention]

The following is a brief description of an effect obtained by the representative one of the inventions disclosed in the present application.

The processing apparatus of the present invention has a structure in which a clean gas is forcibly blown from the upper and lower portions of a spin chuck on which a wafer to be processed is placed and rotated. Further, on the upper surface and the lower surface of the spin chuck, there are provided proximity plates which are arranged at positions where the cleaning water scattered by the centrifugal force does not reach and are reflected, and which makes the gas flow rate flowing in the radial direction uniform. Further, an exhaust mechanism for forced exhaust is provided at the periphery of the processing chamber constituted by a pair of proximity plates. The exhaust mechanism exhausts the gas in the processing chamber by an ejector action. For these reasons, in the spin drying of the wafer, the cleaning water scattered by the centrifugal force does not reflect on the proximity plate and adhere to the wafer surface, and clean gas is supplied to the center of the upper surface and the lower surface of the spin chuck. In addition, the gas flows uniformly due to the proximity plate, and because it is forcibly exhausted by the ejector action, the gas flow becomes a laminar flow and flows in the processing chamber in a radial direction without stagnation. Can be achieved

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of a drying apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view showing an essential part of a drying apparatus according to another embodiment of the present invention. 1 ... Wafer, 2 ... Spin chuck, 3 ... Spin motor, 4 ... Rotation axis, 5 ... Proximity plate, 6 ... Processing chamber, 7,
8 …… Dispersion hole, 9 …… Clean air, 10,11 …… Clean air supply part, 12,13 …… Clean air supply pipe, 14 …… Seal, 15 …… Bounce prevention cylinder, 16 …… Exhaust part, 17 …… Exhaust pipe, 18 …… Intake hole, 19 …… Air, 20
...... Exhaust gas, 21 …… Coma chuck, 22 …… Cleaning water, 23
…… Replacement gas, 24 …… Cavity, 25 …… Microwave generator, 26 …… Microwave, 27 …… Exhaust and drainage section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuaki Sato, No. 502, Jinritsucho, Tsuchiura City Machinery Research Laboratory, Hitachi Ltd. (56) References JP-A-54-73475 (JP, A) JP-A-55- 86116 (JP, A) JP 60-64436 (JP, A) JP 60-74438 (JP, A) JP 57-45928 (JP, A) JP 60-83333 (JP, A) JP-A-57-178328 (JP, A) JP-A-57-36833 (JP, A)

Claims (1)

(57) [Claims] 1. A holding portion for holding an object to be processed, and the holding portion such that the space height near the inside of the end is narrower than the center and the space height of the end is wider than that near the inside of the end. And a means for supplying a clean fluid between the proximity plate and the object to be processed;
And a discharge mechanism provided around the proximity plate and having an intake hole for sucking gas.