JP2767165B2 - Wafer cleaning tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer cleaning tank for cleaning semiconductor wafers by immersing them one by one in a cleaning liquid substantially vertically.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, impurities adhering to the surface of a semiconductor wafer adversely affect the performance of the semiconductor device.

[0003] Therefore, the manufacturing process of a semiconductor wafer includes a cleaning process. In this cleaning process, the wafer is cleaned by various methods. The method of cleaning a wafer is roughly classified into a physical cleaning method. There is a chemical cleaning method.

[0004] As the former physical cleaning method, a method of directly removing impurities adhered to the wafer surface using a cleaning brush or the like, a method in which a pressurized fluid is jetted from a jet nozzle toward a part or the whole of the wafer, Thus, there are a method of removing impurities, a method of immersing a wafer in a liquid and applying ultrasonic waves to the wafer to remove impurities attached to the wafer (ultrasonic cleaning method), and the like.

[0005] The latter chemical cleaning methods include:
There is a method of chemically decomposing and removing impurities attached to the wafer surface by various chemicals, enzymes and the like. Incidentally, a physical cleaning method and a chemical cleaning method may be used in combination.

[0006]

In the field of semiconductor manufacturing, semiconductor wafers have become larger in diameter with the recent trend toward higher integration of semiconductor devices, and a plurality of wafers are accommodated in a carrier for cleaning. According to the conventional method, a great deal of labor is required.

[0007] In addition, if a method is adopted in which a wafer is accommodated in a carrier and transported, there is also a problem that particles or the like adhere to the wafer due to contact between the wafer and the carrier and the wafer is contaminated.

Therefore, a wafer-by-wafer type automatic wafer cleaning apparatus for cleaning wafers one by one by supporting wafers one by one substantially vertically and sequentially immersing the wafers in a cleaning solution in a plurality of cleaning tanks has been proposed. You.

In such a wafer-by-wafer automatic cleaning apparatus, it is necessary to immerse one wafer in a cleaning liquid in a state where one wafer is stably supported substantially vertically in each cleaning tank. Requires special ingenuity.

The present invention has been made based on the above circumstances, and an object of the present invention is to immerse a wafer in a cleaning liquid in a state where the wafers are stably supported substantially vertically one by one and to wash the wafer. A cleaning tank is provided.

[0011]

In order to achieve the above object ,
The wafer cleaning tank according to the present invention includes the steps of:
It is immersed one by one almost vertically to wash it.
Te, a flat tank provided in the longitudinal direction for accommodating the cleaning liquid,
A holder configured to support the wafer substantially vertically in the tank, and a spray nozzle configured to spray a cleaning liquid toward an upper surface of the wafer supported by the holder;
Is a wafer that receives a pressing force from the jet cleaning liquid.
Abut on the back and tilt it slightly to the vertical
The feature is to support .

[0012]

According to the present invention, one wafer is immersed in the cleaning liquid in the tank and washed while being stably supported substantially vertically by the holder. At this time, the wafer receives the cleaning liquid ejected from the injection nozzle at its upper part, is pressed by the holder, is supported in a state of being slightly inclined with respect to the vertical, and its posture is kept stable.

[0013]

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

FIGS. 7, 8, and 9 are a front view, a plan view, and a side view of an automatic wafer cleaning apparatus having a wafer cleaning tank according to the present invention. The automatic wafer cleaning apparatus includes a loader section A and a wafer receiving tank. B, preliminary cleaning tank C, brush cleaning tank D, cleaning tanks E, F, G, H, I, two preliminary tanks J, K,
It has a drying tank L and an unloader section M.

The wafers W whose surfaces have been mirror-polished in the polishing step, which is the preceding step, are continuously loaded one by one into the loader section A as shown in FIG.
The wafer is sent into the wafer receiving tank B along the flow of pure water.

The wafer receiving tank B is provided with a wafer erecting device (not shown), and the wafer W carried into the wafer receiving tank B is erected by the wafer erecting device. Then, the vertically erected wafer W is vertically supported by the transfer robot 20 and automatically transferred from the wafer receiving tank B to the pre-cleaning tank C.
In the pre-cleaning tank C, the wax immersed in the cleaning liquid and attached to the back surface is removed. Then, the wafer W from which the wax has been removed in the pre-cleaning tank C is transferred to the transfer robot 20.
The brush cleaning tank D is vertically supported and sent to the brush cleaning tank D, where both surfaces thereof are simultaneously brush-cleaned to remove particles and the like.

The wafer W brush-cleaned as described above.
Is vertically supported by the transfer robot 20 and transferred to the cleaning tank E according to the present invention, where it is rinsed.

Here, the structure of the cleaning tank E will be described with reference to FIGS. FIG. 1 is a cutaway front view of the cleaning tank E,
2 is a plan view of the same, FIG. 3 is a cutaway side view of the same, and FIG.
FIG. 5 is a view in the direction of arrow h in FIG. 1, and FIG. 6 is a flow sheet of the cleaning tank.

The washing tank E has a flat tank 110, and the long wall surface of the tank 110 (the long wall surface is a plane in FIG. 2).
In the figure, it means the wall surface in the left-right direction. The following theory
In FIG. 2, the “long side direction” refers to the horizontal direction in FIG.
"Side direction" means the vertical direction in FIG.
You. 2) , an overflow tank 111 is formed, and an overflow pipe 112 is connected to the bottom of the overflow tank 111. The overflow pipe 112 is connected to a drain line 132 shown in FIG.

A drain pipe 113 is connected to the bottom of the tank 110. As shown in FIGS. 1 and 5, the bottom of the tank 110 is inclined downward toward the drain pipe 113 in the long side direction. , Are also inclined downward toward one side in the short side direction. Accordingly, contaminants and the like that fall to the bottom of the tank 110 first move to one side in the width direction along the inclination of the bottom surface of the tank 110 in the short side direction, and further move in the direction of the drain pipe 113 along the inclination in the long side direction. All of which flows from the drain pipe 113 to the tank 110
Since it is discharged to the outside, no pollutant or the like accumulates at the bottom of the tank 110.

Further, in FIG. 3, a chamber S defined by a cover member 114 which is long in the longitudinal direction is formed above the tank 110. The chamber S has a water supply pipe of a water supply line 115 shown in FIG. 116 is connected. As shown in detail in FIG. 4, the chamber S communicates with the inside of the tank 110 through a plurality of injection nozzles 117. The injection nozzles 117 are provided to be inclined downward toward the inside of the tank 110.

The water supply pipe 116 of the tank 110
Below, a water supply pipe 118 also connected to a water supply line 115 (see FIG. 6) is connected. FIG.
In the figure, 119 is a chemical supply pipe.

On the other hand, a rectangular frame-shaped holder 120 for supporting the wafer W in a slightly inclined state with respect to the vertical is accommodated in the tank 110. On the left and right sides of the lower end of the holder 120, two rollers 121, 121 having a concave portion on the outer periphery to support the outer peripheral portion of the wafer W are rotatably journaled. As shown in FIG. 2, the key portion 120a formed on the upper end
By being hooked on the upper edge of the tank 10, the tank 1
It is supported vertically in 10.

As shown in FIG. 6, the entire cleaning tank E is immersed in a tank 122 filled with pure water, and an ultrasonic oscillator 123 is mounted below the tank 122.

As shown in FIG. 1, the wafer W supported by the transfer robot 20 (see FIGS. 7 to 9) is in a state where the outer peripheral portion is supported by the rollers 121 of the holder 120. Are immersed in pure water in a tank 110, and the plurality of injection nozzles 117 (FIG. 4)
3) is received by the holder 120 in a state of being slightly inclined with respect to the vertical as shown in FIG. 3, and its posture is kept stable. At this time, as described above, the injection nozzles 117.
Is inclined downward toward the inside of the tank 110 (wafer W), the wafer W is pressed by the rollers 121 and 121 under a downward force, and the floating in pure water is suppressed. The posture is kept stable. The pure water is supplied into the tank 110 from the spray nozzles 117 and the water supply pipe 118, and the pure water overflowing from the tank 110 to the overflow tank 111 is discharged from the overflow pipe 112 to a discharge line 132 (see FIG. 6). You.

In the above state, the entire cleaning tank E is subjected to ultrasonic vibration by the ultrasonic oscillator 123,
Inside, the wafer W supported substantially vertically by the holder 120
Is rinsed with pure water.

Next, the cleaning tank F will be described. The configuration of the cleaning tank F is the same as that of the cleaning tank E.
As shown in the figure, a tank 124 is provided below the cleaning tank F.

Different kinds of chemicals are supplied into the tank 124 through the lines 125 and 126, respectively, and one of the chemicals is pressurized by the pump 127 and then brought to a predetermined temperature (about 80 ° C.) by the line heater 128. It is heated and passed through the filter 129 to be supplied into the cleaning tank F.

On the other hand, the wafer W rinsed in the cleaning tank E is handled by the transfer robot 20 and taken out of the cleaning tank E, then transferred to the cleaning tank F, and cleaned in the same state as shown in FIG. The particles immersed in the chemical solution in the tank F and attached to the surface thereof are removed.

Incidentally, the wafer W from which particles have been removed in the cleaning tank F is at a high temperature (about 80 ° C.).
The high-temperature chemical solution in the cleaning tank F is returned from the line 130 shown in FIG.
Pure water is supplied into the cleaning tank F from 5, and the wafer W is rapidly cooled by the pure water. Then, the pure water used for cooling the wafer W is discharged from the line 131 to the drain line 132.

The structure of the cleaning tanks G, H, and I is the same as that of the cleaning tanks E and F. The wafer W cleaned in the cleaning tank H is transferred by the transfer robot 20 to the cleaning tanks G and H. , I are sequentially conveyed, and the wafer W is rinsed with pure water in the cleaning tanks G and I, and washed with a chemical solution in the cleaning tank H to remove ionic impurities attached to the surface.

The wafer W cleaned by the pre-cleaning tanks C to I is conveyed to the drying tank L by the transfer robot 20 and quickly dried, and then transferred from the drying tank L by the transfer robot 20. The wafers W are taken out and stored in the unloader section M one by one in a wafer cassette 151 (not shown), and the wafers W are successively and automatically cleaned one by one.

As described above, the automatic cleaning apparatus according to the present embodiment is of a single-wafer type, and each wafer W is accurately and stably positioned in each of the cleaning tanks E to I. The sheets are stably supported and transported one by one by 20.
And it is processed continuously. As a result, a conventionally used carrier is not required, and so-called carrier-less can be realized, and it is possible to easily cope with automation of cleaning.

[0034]

As is apparent from the above description, the present invention is not limited to this.
In the wafer cleaning tank, a flat tank provided in the vertical direction for storing the cleaning liquid, a holder for supporting the wafer substantially vertically in the tank, and an upper surface of the wafer supported by the holder. construction of and a jet nozzle for jetting a cleaning liquid
The holder receives a pressing force from the jetted cleaning liquid.
Contact the back of the wafer to be
Since the wafers are supported in a tilted state, it is possible to obtain an effect that the wafers can be washed by being immersed in a cleaning liquid while being stably supported substantially vertically one by one. In addition, a plurality of cleaning tanks having the above configuration are provided,
In a cleaning device that sequentially cleans wafers in a tank,
Since the positioning of the wafer is performed with high precision in each cleaning tank, carrier-less operation can be realized, and it is possible to easily cope with automation of the cleaning apparatus .

[Brief description of the drawings]

FIG. 1 is a cutaway front view of a cleaning tank according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a cutaway side view of FIG . 1;

FIG. 4 is an enlarged detail view of a portion g in FIG. 3;

FIG. 5 is a view in the direction of arrow h in FIG. 1;

FIG. 6 is a flow sheet of a cleaning tank.

FIG. 7 is a front view of the automatic wafer cleaning apparatus.

FIG. 8 is a plan view of FIG . 7;

FIG. 9 is a side view of FIG . 7;

[Explanation of symbols]

 110 tank 111 overflow tank 113 drain pipe 117 injection nozzle 120 holder 121 roller EI cleaning tank

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiharu Kimura Fukushima Prefecture Nishishirakawa-gun Nishigo-mura Odakura-shi Ohira 150 Semiconductor-Shirakawa Research Laboratories Shin-Etsu Semiconductor Co., Ltd. Odakura Ohira 150 Address Shin-Etsu Semiconductor Co., Ltd. Semiconductor Shirakawa Laboratory (56) References JP-A-3-124028 (JP, A) JP-A-60-14244 (JP, A) JP-A-2-207526 (JP, A) JP-A-60-143634 (JP, A) JP-A-60-257140 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/304 H01L 21/68

Claims (5)

(57) [Claims] 1. A cleaning tank for immersing wafers one by one in a cleaning liquid substantially vertically one by one to wash the cleaning liquid, wherein a flat tank provided in a vertical direction for storing the cleaning liquid, and the wafer is disposed substantially vertically in the tank. And a spray nozzle for spraying a cleaning liquid toward an upper surface of a wafer supported by the holder.
Abuts against the back of the wafer that receives the pressing force from the clean solution,
A wafer cleaning tank characterized in that it is supported in a slightly inclined state with respect to a vertical plane . 2. The wafer cleaning tank according to claim 1, wherein the tank is provided with an overflow tank for keeping the level of the cleaning liquid in the tank constant. 3. A drain pipe is connected to a bottom portion of the tank, and a bottom surface of the tank is inclined downward toward the drain pipe in a long side direction and toward one side in a short side direction. 3. The wafer cleaning tank according to claim 1, wherein the wafer cleaning tank is inclined downward. 4. The holder is detachably attached to the tank, and has two lower rollers rotatably supported at its lower end, each of which has a recess on the outer periphery to support the outer periphery of the wafer. 4. The wafer cleaning tank according to claim 1, wherein an upper end of the wafer supported by the roller is maintained substantially vertically using a side wall of the tank. 5. The spray nozzle includes one or more nozzles that spray a cleaning liquid at an angle in a horizontal or / and downward direction toward the inside of the tank to prevent a wafer from floating in the cleaning liquid. 5. The wafer cleaning tank according to claim 1, wherein the cleaning is assisted.