JP2859624B2 - Single wafer type cleaning apparatus and cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a single-wafer cleaning apparatus and a cleaning method that are optimally used for cleaning in, for example, a semiconductor wafer manufacturing process.

[Prior art]

Cleaning semiconductor wafers is one of the essential tasks in the manufacture of semiconductor devices, especially ICs. At the time of this cleaning, a jig such as a boat is used to hold the wafers at predetermined intervals in the processing tank.

[Problems to be solved by the invention]

Therefore, the contact portion between the wafer and the boat and the vicinity thereof have poor cleaning efficiency, which often causes dirt. Further, waste remains on the boat, and the possibility of reverse contamination of the wafer to be processed next from the boat cannot be ignored. When a large number of wafers are accommodated in one processing tank for cleaning, even if the chemical solution is circulated using a chemical solution circulation system, contaminated chemical solution cannot be avoided to adhere to the wafers and boats. As a result, the cleaning performance was reduced. In particular, these issues have become increasingly important problems that cannot be ignored with the development of highly integrated technologies of 1Μ, 4Μ, and 16Μ.

[Means for Solving the Problems]

According to a first aspect of the present invention, there is provided a single-wafer cleaning apparatus including a processing tank for storing one workpiece and a cleaning supply unit for supplying a cleaning liquid to the processing tank.
It is characterized in that the cleaning liquid is mixed in the processing tank. According to the single-wafer cleaning apparatus of the first aspect, for example, H ₂ SO ₄ and H ₂ O ₂
By mixing a cleaning liquid such as the one described above, the cleaning liquid reacts to generate reaction heat, thereby increasing the cleaning efficiency. In the single-wafer cleaning apparatus according to the first aspect, as described in the second aspect, the cleaning liquid supply unit is configured to overflow the cleaning liquid from inside the processing tank while supplying the cleaning liquid into the processing tank. It may be. Then, by continuously supplying the cleaning liquid into the processing tank and causing it to overflow, the object to be processed can always be cleaned with a new cleaning liquid. Further, as described in claim 3, the cleaning liquid supply means may be configured to supply the cleaning liquid recovered from the inside of the processing tank to the processing tank again after regeneration. Then, waste of the cleaning liquid is eliminated, and the cost is reduced. Further, as described in claim 4, an ultrasonic vibration unit for applying ultrasonic vibration to the cleaning liquid in the processing tank may be provided. Then, by applying ultrasonic vibration to the cleaning liquid, the chemical reaction of the cleaning liquid is promoted, and more effective cleaning can be performed. According to a fifth aspect of the present invention, there is provided a cleaning method using the single-wafer cleaning apparatus according to any one of the first to fourth aspects, wherein the cleaning method includes an aqueous solution of sulfuric acid and hydrogen peroxide mixed in the treatment tank. 1
After the object to be processed is washed with the chemical solution of the above, a second solution containing an aqueous solution of ammonia and hydrogen peroxide mixed in the processing tank is used.
The object to be processed is washed with the chemical solution.

【Example】

Next, an embodiment in which the single-wafer cleaning apparatus and the cleaning method of the present invention are applied to the cleaning of a single-wafer dip-type semiconductor wafer will be described with reference to FIG. 1 and FIG. In the figure showing a single-wafer dip type semiconductor wafer cleaning apparatus, a closed processing tank 2 is a box with a bottom and is made of, for example, Teflon or quartz having a good corrosion resistance to chemicals L ₁ and L ₂ . An aqueous solution of sulfuric acid (H ₂ SO ₄ ) and aqueous hydrogen peroxide (H ₂ O ₂ ) is used as the first chemical solution L ₁ for cleaning the wafer W, and ammonia is used as the second chemical solution L ₂ An aqueous solution of (NH ₄ OH) and aqueous hydrogen peroxide (H ₂ O ₂ ) is employed. In the drug solution L _1, H ₂ SO ₄ and H ₂ ratio of O ₂ is 4: 1 is desirable, also in the chemical L _2, a ratio of NH ₄ OH and H ₂ O _2, H ₂ O is 1: 1: 5 Is desirable. Inside the processing tank 2 installed inside the whole apparatus 1,
A plurality of individual processing tanks 21 are arranged at predetermined intervals.
As shown in FIG. 1, the individual processing tank 21 has a space 21G for accommodating a wafer W in a combination of inners 21B, 21C, 21D and wedges 21E, 21F inside an outer tank 21A.
Is provided with a notch 21H for chucking the wafer W. The inner 21D is provided with a groove 21 # for holding the wafer W upright in the accommodation space 21G. The inner 21D may be provided not only in one piece but also in plural pieces to hold the wafer W. The outer tank 21A has four pipes 21I.21J, 2
1K and 21L are provided, 21I and 21J are chemical supply pipes, 21K is an overflow pipe for discharging the overflowed chemical when the wafer W is subjected to overflow processing, and 21L is a chemical discharge after processing the wafer W. Used as a drain tube for A rod-like cap 22 having a length substantially equal to the width of the wafer W is attached to an upper opening of each individual processing tank 21. This cap 22 has a cover with an upper opening 23A and a lower opening 23B.
23, the both ends are fitted into the arc-shaped groove 24 of the side plate 23C erected at both ends in the length direction, and the arc-shaped groove is connected to the rotation shaft 25 and the arm 26 which are pivotally mounted on the round hole 23D which is the fan-shaped center of the arc-shaped groove 24. 24, is driven by a drive source 30 such as a motor or an air cylinder connected to the rotating shaft 25 by the universal joints 27 and 28 and the connecting shaft 29, and is individually positioned at the lower end of the arc-shaped groove 24. The upper opening of the processing tank 21 is closed. The lid 4 is provided on the upper part of the individual processing tank 21 via the seal 3, and the individual processing tank 21 is mounted on the lid 4 via the seal 5. The drain pipe 21L of each individual processing tank 21 penetrates the processing tank 2 and is attached using a bush 6 with a seal.
The drain tube 14 and the air valve 15 are attached ahead of it. A heater 7 for heat-controlling the pure water filled in the processing tank 2 is attached to a lower portion of the processing tank 2 by using a bush 8 with a seal. Mounted through. In the processing tank 2, a pure water supply pipe, a liquid temperature sensor, an exhaust pipe,
Liquid upper limit level sensor, liquid lower limit level sensor (not shown)
Is attached to the connection hole 4A of the lid 4. Connection hole 2A of processing tank 2
Is connected to the drain tube 21L, and a drain tube 13 is attached to the connection hole 2B to allow pure water to escape if the water enters too much. The pure water in the processing tank 2 is always filled to keep the temperature of the individual processing tank 21 and protect the ultrasonic vibrator 9. On the side of the processing tank 2, three chemical liquid supply systems and a pure water supply system are provided. The chemical supply system 16 is shown in detail in FIG. The chemical solution stored in the storage tank 161 is sent to the measuring tank 165 via the filter 163 and the air valve 164 by the pump 162.
From the measuring tank 165, it is sent to the individual processing tank 21 by natural fall via the air valve 166. Normally, the chemical liquid is supplied to the filter 163 and the air valve 16 by the pump 162.
7 (the air valve 164 is closed), the fuel is returned to the storage tank 161 and circulated. When the chemical liquid in the measuring tank 165 is exhausted to the lower limit level, the air valve 167 is closed, the air valve 164 is opened, and the measuring tank 16 is opened.
Sent to 5. H ₂ SO ₄ , H ₂ O ₂ , and NH ₄ OH are provided in three storage tanks provided corresponding to the respective chemical liquid supply systems 16.
Are stored separately. For example, Teflon or quartz is used as a material for the pipes of the supply systems 16 and 17, and the pipes have excellent corrosion resistance to the chemicals L ₁ and L ₂ . Pump 162
The delivery capacity is set to about 10 to 30 / min, chemical supply pipe 21I, the flow rate of the liquid medicine L _1, L ₂ entering from 21J is set to about 3 to 10 / min. Assuming that the individual processing tanks 21 are A, B, C, and D from the left in FIG. 2, the processing liquids used in this embodiment are chemical liquid L _{1 for} A, pure water for B, and chemical liquids L ₂ and D for C in this embodiment. Although pure water is used, the number of the processing tanks 2 is further increased to two tanks, and the individual processing tanks of the first processing tank 2 are used.
The chemical liquid L ₁ , the chemical liquid L ₁ , pure water, and pure water are used for 21, and the chemical liquid L ₂ and the chemical liquid are respectively used for the individual processing tanks 21 of the second processing tank 2.
L ₂ , pure or pure may be used, and other combinations are also possible. In this embodiment the drug solution L ₁ in separate treatment tank 21 A is used, chemical L ₁ are mixed in a separate processing bath 21. That is, H ₂ SO ₄ is supplied from the chemical supply pipe 21I to the chemical supply pipe 21I.
It is supplied H ₂ O ₂ from J is mixed in a separate processing tank 21, the liquid medicine L ₁ of hot (approximately 0.99 ° C.) with vigorous reaction. NH ₄ OH is supplied from the individual treatment tank 21I of C, and H ₂ O ₂ is supplied from the chemical supply pipe 21J, and mixed in the tank. In the individual treatment tanks B and D, pure water is supplied from chemical supply pipes 21I and 21J. Next, the operation of the above configuration will be sequentially described. First, a wafer W that has been subjected to resist coating or ashing processing is placed in the individual processing tank 21 of A. Air valve 166 of H ₂ SO ₄ chemical supply system 16
The predetermined time (individual processing tank 21 to fill with liquid chemical) opened each H ₂ SO ₄ from the metering chamber 165 and H ₂ O ₂ and a chemical liquid supply pipe 21I, when dropped from 21J, both chemical liquid vigorous chemical reaction The temperature of the wafer W rises to a high temperature (about 150 ° C.), and the surface of the wafer W is cleaned. During this time, both surfaces of the wafer W are effectively cleaned while the ultrasonic vibrator 9 operates to promote a chemical reaction.
The cleaning time varies depending on the wafer W to be processed.
About 20 seconds to 3 minutes. After a lapse of a predetermined time, open the air valve 15,
It drained the liquid medicine L ₁ of the individual processing bath 21 A, withdrawing the wafer W. Next, the drawn wafer W is put into the individual processing tank 21 of B,
Pure water is injected from the pure supply system 17 through the chemical supply pipes 21I and 21J, and the pure water is washed. In the case of pure cleaning, pure is supplied during the processing time, and the
Drained from 21K. During this time, the ultrasonic vibrator 9 operates to promote cleaning. After a predetermined time has elapsed, open the air valve 15 and
The pure water in the individual processing tank 21 is drained, the wafer W is pulled out,
C is put into the individual processing tank 21. C Individual treatment tank 21 in the chemical supply pipe 21I, and each supply the NH ₄ OH, H ₂ O ₂ than 21J, to clean the surface of the wafer W satisfies the evening liquid L ₂ in the tank. During this time, the ultrasonic vibrator 9 operates to effectively clean both surfaces of the wafer W while promoting the chemical reaction. The above cleaning time is about
20 seconds to 3 minutes. After a predetermined time has elapsed, open the air valve 15 and
Of drained the liquid medicine L ₂ of the individual processing bath 21 pull the wafer W is placed in a separate treatment tank 21 of D. In the individual processing tank 21 of D, pure water is supplied from the chemical supply pipes 21I and 21J as in B to overflow and clean. During this time, the ultrasonic vibrator 9
Operates to facilitate cleaning. After a predetermined time has elapsed, the air valve 15 is opened, the pure water in the individual processing tank 21 of D is drained, and the wafer W is taken out, whereby the cleaning process is completed. Next, FIG. 4 shows another embodiment of the single-wafer cleaning apparatus and the cleaning method of the present invention. The processing tank 41 is provided with a wafer fixing table 43 having a predetermined height and an ultrasonic vibrator 42 at the bottom, and a quartz tube heater 44 disposed around the wafer fixing table 43. The upper part of the wafer fixing table 43 is opened, and ultrasonic nozzles 45, 4
6 is installed. The H ₂ SO ₄ of the chemical solution L ₁ is blown out of the ultrasonic nozzle 45 via the high-temperature pump 47, and the H ₂ O ₂ is blown out of the ultrasonic nozzle 46 via the pump 48, to the wafer fixing table 43. The surface of the set wafer W is cleaned. On the other hand, these aqueous solutions are supplied to the processing tank 41 and the chemical liquid reprocessing apparatus.
Reproduction processing is performed by circulating between 49. That is, the chemical liquid regeneration processing device 49 includes the drainage storage tank 50 and the regeneration liquid storage tank.
51, between which a filter 52 is provided to regenerate. 53 and 54 are high-temperature pumps or pumps, respectively. And the drainage port of the processing tank 41
Chemical L ₁ which is forwarded to the drainage reservoir 50 through 55, the pump
At 54, it is sent to the filtration device 52, stored in the regenerating storage tank 51, and sent from the high-temperature pump 53 to the processing tank 41 via the liquid supply port 56 as necessary. At this time, the wafer W immersed in the chemical solution L _1, the lower surface is also cleaned by the ultrasonic transducer 42 provided in the bottom of the wafer fixing stand 43. Similar equipment is provided separately, NH ₄ OH and H ₂ O ₂
Chemical L ₂ consisting of is then applied to both surfaces of the wafer W subjected to the cleaning process. The cleaning time with the chemicals L ₁ and L ₂ may be the same as in the above embodiment. By the way, the present invention is not limited to the above-described embodiments, and various modifications are conceivable. For example, the number of individual processing tanks and the number of ultrasonic nozzles are not limited to the embodiment, and may be larger or smaller. Furthermore, treatment tank 2,41
Can take various forms according to the shape of the wafer. In the above embodiment, the case where the present invention is applied to cleaning of a semiconductor wafer has been described. However, any cleaning process may be used, such as cleaning of an LCD substrate or a substrate on which a TFT circuit is formed.

【The invention's effect】

As is apparent from the above description, in the wafer cleaning process, the wafers are treated one by one with the individual chemicals, so that the wafers do not come into contact with the chemicals contaminated by the cleaning of other wafers, and furthermore, the reverse contamination occurs. There is no danger at all. Accordingly, there is an excellent effect that the cleaning efficiency can be remarkably improved in response to the increase in the diameter and the quality of the wafer.

[Brief description of the drawings]

1 is a cross-sectional view of a main part of a wafer cleaning apparatus to which the present invention is applied, FIG. 2 is a vertical cross-sectional view of a main part, FIG. 3 is a configuration diagram of a chemical solution supply system 16, and FIG. FIG. DESCRIPTION OF SYMBOLS 1 ... Device main body 2, ... Processing tank 9 ... Ultrasonic vibrator, 16 ... Chemical solution supply system 21 ... Individual processing tank, 22 ... Bar-shaped cap 23 ... Guide, 24 ... Arc-shaped groove 25 ... Rotating shaft, 26 Arm 30 Drive source 41 Processing tank 42 Ultrasonic vibrator 43 Wafer holder 44 44 Quartz tube heater 45, 46 Ultrasonic nozzle 47 High temperature Pump, 48 Pump 49 Chemical regeneration unit 50 Drain tank 51 Regenerated tank 52 Filtration device 53 High temperature pump 54 Pump 55 Drain outlet 56: Liquid supply port, W: Wafer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takenobu Matsuo 1-26-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Inside Tokyo Electron Limited (72) Inventor Kazuei Shimura 1-26 Nishi Shinjuku, Shinjuku-ku, Tokyo No. 2 Tokyo Electron Co., Ltd. (72) Inventor Masami Hanui 48, Jodoji Kamibabacho, Sakyo-ku, Kyoto-shi, Kyoto (72) Inventor Hiroshi Yamaguchi 191-1-232 Matsuyacho, Neyagawa-shi, Osaka (72 ) Inventor Tetsuo Koyanagi 2-15-15 Osumigaoka, Tanabe-cho, Tetsuki-gun, Kyoto (56) References JP-A-64-19740 (JP, A) JP-A-60-247928 (JP, A) JP-A-60 JP-239028 (JP, A) JP-A-61-40034 (JP, A) JP-A-61-86929 (JP, U)

Claims (5)

(57) [Claims] 1. A single-wafer cleaning apparatus comprising: a processing tank for accommodating a single object to be processed; and a cleaning liquid supply unit for supplying a cleaning liquid to the processing tank. A single-wafer cleaning apparatus characterized by being configured to mix a cleaning liquid. 2. The cleaning liquid supply means is configured to supply a cleaning liquid into the processing tank and to overflow the cleaning liquid from within the processing tank.
The single-wafer cleaning apparatus according to claim 1. 3. The method according to claim 1, wherein the cleaning supply unit is configured to supply the cleaning liquid recovered from the processing tank to the processing tank again after regeneration. Single wafer cleaning equipment. 4. A single-wafer cleaning according to claim 1, further comprising an ultrasonic vibration means for applying ultrasonic vibration to the cleaning liquid in the processing tank. apparatus. 5. A cleaning method using the single-wafer cleaning apparatus according to claim 1, wherein the sulfuric acid and the hydrogen peroxide solution mixed in the processing tank are provided. After the object is washed with a first chemical solution containing an aqueous solution, the object is washed with a second chemical solution containing an aqueous solution of ammonia and hydrogen peroxide mixed in the treatment tank. Cleaning method.