JP2005032948A - Method for cleaning semiconductor wafer and cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for cleaning a semiconductor wafer that is highly effective in cleaning and can save an operating cost and to seek for a cleaning method therefor. <P>SOLUTION: A movable cap provided with a spray nozzle lowers and covers a wafer to spray and clean it, then the movable cap is lifted up from the wafer, and the wafer is transferred to a next station. Single or a plurality of individual stations are provided in each of units in a cleaning step, a rinsing step and a drying step, and wafers are simultaneously transferred at a specified tact time. The wafer is dried by jetting a dry air and spinning at high speed. A splash of a washing liquid and a rinsing liquid is liquefied and reused in each station. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor wafer cleaning method and a cleaning apparatus.
[0002]
[Prior art]
The horizontal mounting cleaning of semiconductor wafers can be found in the following publication of Patent Document 1.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-7665 discloses a cleaning device that is effective in preventing wafer cracking. In paragraph [0048] of the publication, “the cleaning liquid can be sprayed from the upper part of the wafer, and therefore, as shown in FIG. Is described.
[0004]
The position of the cleaning nozzle shown in FIG. 8 is on the surface of the semiconductor wafer, directly above the solder bumps of the sphere. Since it is sprayed, the cleaning area is small, the nozzle is scanned uniformly, the cleaning liquid is sprayed over the entire surface of the wafer, and cleaning takes time.
[0005]
FIG. 6 is a structural diagram showing the inside of a cleaning unit in a conventional apparatus manufactured by the inventors. While the wafers 11, 12, and 13 are placed on the wafer conveyor 14 and gradually move in the direction of the arrow, the wafer is cleaned by the cleaning liquid sprayed from the nozzle 16. The wafer put in from the carry-in port 17 moves in the direction of the arrow, and the cleaned wafer is taken out from the carry-out port 18 and transferred to the next process.
[0006]
In the case of such an apparatus that takes time for cleaning, there is a disadvantage that the cleaning wafer conveyor is long and requires a large space, and requires a large installation area.
[0007]
Further, as a disadvantage, a large amount of cleaning mist is generated and the mist drifts out from the carry-in port 17 and the carry-out port 18, and is exhausted together with air through the exhaust duct 20. For this reason, the loss of the cleaning liquid has become a factor that increases the operating cost of this apparatus.
[0008]
[Problems to be solved by the invention]
The problem is to provide a cleaning device that has a high cleaning effect on solder waste and flux of semiconductor wafers, can save installation space, and can reduce operating costs. In order to solve the problem accurately, it is necessary to first find the optimum cleaning method.
[0009]
[Means for solving the problems]
(Overall configuration) An individual station having a movable cap that covers the semiconductor wafer and fixedly mounting the semiconductor wafer with a chuck, a cleaning process unit, a rinse process unit, and a drying process in which one or more individual stations are accommodated A unit, and a transport control means and a transport mechanism for transporting the semiconductor wafers simultaneously at a tact time determined in conjunction with the up and down movement of the movable cap, and a cleaning liquid tank, a rinsing liquid tank, a cleaning liquid and a rinsing liquid injection A liquid pump provided with a liquid pump discharge adjusting means capable of adjusting the pressure and the amount of spray liquid, and a cleaning device in which the liquid spray pressure and the spray liquid amount are set to predetermined values for each individual station.
[0010]
(Related to injection)
A cap provided with an injection nozzle is provided at an individual station so that it covers the wafer set at the individual station, and the injection nozzle can be swung or fixed at an angle so that the angle of the injection nozzle can be changed. The cleaning device is connected to the liquid tank via a liquid pump through a liquid pump.
[0011]
(Relation between cleaning and spray angle)
One or a plurality of spray nozzles are provided for each station so as to be on the top of the semiconductor wafer, and cleaning can be performed in a range of 10 ° ≦ θ ≦ 30 ° from the liquid spray angle θ from the nozzle with respect to the horizontal plane of the semiconductor wafer. The device.
[0012]
(Related to wafer transfer)
The semiconductor wafer is moved laterally from the first station to the second station and then to the third station so that the wafers are transferred to the cleaning process, the rinsing process, and the drying process one after another at a determined tact time. The timing for picking up the semiconductor wafer from the left and right with the chuck and moving to the next process is within the period when the cap is open and the stage where the semiconductor wafer is to be placed is empty. Thus, a cleaning apparatus including a transfer control means and a transfer mechanism to control the above was used.
[0013]
(Related to wafer fixing)
The semiconductor wafer chucked from the left and right sides of the wafer and transferred by lateral movement was fixed to a cleaning apparatus having a fixing mechanism that is fixed by chucking from the front and rear sides of the semiconductor wafer.
[0014]
(Related to rotation control)
At the timing when the semiconductor wafer is transferred to the drying process, the lower surface of the wafer is fixed to a spin table having a vacuum suction means, and the wafer is rotated at a high speed to be centrifugally dried. After a predetermined time, the rotation is stopped. The cleaning apparatus was provided with a rotation control means for stopping vacuum suction.
[0015]
(Related to air drying)
The dry air is spouted from the opening of the dry air supply pipe onto the surface of the semiconductor wafer, and at the same time, the operation of driving the movable cap so as to cover the semiconductor wafer is interlocked with the back surface of the semiconductor wafer fixed to the spin table. The dry air supply pipe is provided with a drying means connected to the dry air generating means by an air guide tube so that the dry air is ejected from the opening of the dry air supply pipe to the back surface of the wafer.
[0016]
(Related to drying)
Drying is performed such that dry air is jetted from the opening of a dry air supply pipe to the front and back surfaces of the semiconductor wafer vacuum-sucked on the spin table, and the spin table is spun dry by rotating the spin table at a high speed. After the movable cap provided with the dry air supply pipe is covered with the semiconductor wafer, the drying process unit is spin-dried by dry air ejection and high speed rotation, and after the dry air ejection and high speed rotation is completed, the movable cap is The cleaning apparatus was provided with interlocking means that moved above the wafer.
[0017]
(About the configuration that reduces the installation space)
An individual station having a movable cap that covers the semiconductor wafer, a cleaning process unit, a rinse process unit, and a drying process unit in which one or more individual stations are accommodated, and a tact determined in conjunction with the opening and closing operation of the cap A means for placing a silicon wafer contained in a magazine on a cleaning stage in a cleaning device comprising a transfer control means and a transfer mechanism for transferring semiconductor wafers simultaneously in time, and comprising a cleaning liquid tank and a rinsing liquid tank. A loader unit was connected to a position close to the cleaning process unit, and a drying process unit comprising a drying means for spin drying by rotating the spin table at a high speed was connected to a rear side position of the unloader unit as an outlet. The cleaning device can save installation space.
[0018]
(About cleaning method)
For the purpose of increasing the number of wafers to be cleaned per hour, semiconductor wafers are transferred from the cleaning stage to the cleaning, rinsing and drying processes one after another in a short tact time, and the surface tension of water is low and the solubility is excellent. A cleaning process of spraying and cleaning composite electrolytic ionic water, which is a mixed water of alkaline electrolytic acid water and acidic electrolytic ionic water, or detergent water at a predetermined spray angle with respect to a semiconductor wafer horizontal plane, pre-rinsing with ion exchange water or composite electrolytic ionic water, and The semiconductor wafer cleaning method is characterized by having a rinsing process including finishing rinsing, centrifugal dehydration by high-speed rotation reaching 3000 rpm, and a spin drying process that does not require hot air by blowing dry air.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an overall configuration diagram of an embodiment according to the present invention. 1A is a front view, FIG. 1B is a side view, and FIG. 2 is an internal perspective view. The washing process unit 2, the rinsing process unit 3 and the drying process unit 4 are connected, and the loader unit 1 is connected to the inlet side, and the unloader unit 5 is coupled to the front of the drying process unit 4 on the outlet side. The semiconductor wafer 11 is transferred to the individual station 23 from cleaning to drying and automatically operated. A semiconductor wafer accommodated in a wafer magazine is set in the loader unit 1. The injection pressure gauge 29 is provided so that it can be seen from the outside of the main body, and the injection pressure of the liquid pump provided with the discharge adjusting means for sucking up the cleaning liquid and the rinsing liquid freely and pressurizing it freely can be seen. However, the pressure is set to a predetermined pressure with a setting knob (not shown), but the pressure and the injection amount with high cleaning power are set within a range not to be damaged according to the thickness of the wafer. The depth dimension D and the height dimension H of the apparatus of this embodiment are determined to be ergonomically appropriate dimensions, but the width W dimension is determined by the cleaning process unit 2 depending on the cleaning tact time requirement. However, in comparison with the conventional method using the wafer conveyor in FIG. 6 with the same tact time, the dimension of the width W can be reduced by 30% in this embodiment.
[0020]
The main part of the cleaning process unit 2 is shown in FIG. 3. The movable cap 22 having the cap shaft 21 through which the liquid introduction pipe is penetrated and provided with the injection nozzle 16 is set on the individual station 23. Immediately after that, the wafer descends downward to cover the wafer, and spray cleaning is performed for 30 seconds. The semiconductor wafer is fixed from the front and back by a chuck so as not to be shaken by the inclined spray liquid. After completion of the cleaning, the movable cap 22 is opened upward, and the semiconductor wafer 11 is picked up from the left and right by the chuck and transferred to the next station. During the period in which the movable cap 22 is opened upward, the wafer is transferred from the previous station. come.
[0021]
The surface of the semiconductor wafer 11 shown in FIG. 4 is provided with one or a plurality of spray nozzles 16 so that the entire surface is cleaned by the cleaning liquid sprayed from the spray nozzles 16. As a result of the experiment, the optimum value of the cleaning liquid injection angle θ from 16 was found. It has been found that the cleaning effect and the cleaning speed are optimal in the range of 10 ° ≦ θ ≦ 30 ° for a semiconductor wafer having a diameter of 8 inches. The spray nozzle 16 is most effective when the cleaning liquid spray angle θ is swingable from 10 ° to 30 ° from the horizontal plane and the angle is set to 20 °. The cleaning of one wafer is completed in about 30 seconds using a general-purpose detergent in the jet cleaning set in this way, and the wafer is moved to the next station 23. In the case of a single nozzle, it is effective to rotate the nozzle along the wafer circumference so that it is uniformly sprayed on the surface of the wafer. When there are a plurality of nozzles, the nozzle is rotated along the wafer circumference. It is effective to use the osmotic power of electrolyzed water as cleaning water for the first station when the mechanism is not required and the pollutant of the object to be cleaned is difficult to peel off. In the case of using composite electrolytic ionic water in which alkaline electrolytic ionic water and acidic electrolytic ionic water are mixed, there is an advantage that equipment necessary for this is simplified and the cost is reduced. This composite electrolytic ionic water is also effective for rinsing.
[0022]
The effect of the movable cap 22 is that the spray of cleaning liquid generates mist during cleaning, and the cleaning liquid or the rinse liquid that has been discharged from the exhaust duct in the past is trapped in the cap and comes into contact with the cleaning or the rinse liquid. It has the effect of returning to the liquid. The effect of using the individual station 23 from the conventional method in which the wafer conveyor 14 is provided in a large cleaning tank contributes to the improvement of the environment in addition to the saving of the cleaning liquid and the rinsing liquid.
[0023]
Wafers are transferred from the first station to the second station, and then to the third station, and the wafers 11 are transferred to the cleaning process, the rinsing process, and the drying process one after another at a determined tact time. Since the discharge pressure adjusting means is provided in the liquid pump so that the injection pressure and the injection liquid amount of the cleaning and rinsing liquid can be set to be strong and weak, and a predetermined value is set for each station and can be monitored by the injection pressure gauge 29. The wafer pressure was too strong to break the wafer. Operation that balances economics such as cleaning speed and water consumption is possible.
[0024]
The wafer 11 transferred to the wafer 11 is fixed by chucking from the front and rear, and cleaning and rinsing are performed. When the movable cap comes down on the wafer and the final rinse process is completed, the process proceeds to the spin drying process at the next station.
[0025]
FIG. 5 shows the internal configuration of the station of the drying process in the embodiment of the present invention. The lower portion of the wafer 11 is fixed by a vacuum suction means, connected to the dry air generating means, and a dry air supply pipe 26 penetratingly formed from the center of the movable cap 22, and dry air 25 and 24 are supplied from below by a dry air supply pipe 27. At the same time, the spin table 28 is rotated by a motor, and spin drying for shaking off the liquid adhering to the wafer 11 is executed. This speed is controlled by the rotation control means so as to obtain a predetermined speed of up to 3000 rpm. It is also effective to provide a power frequency variable inverter for driving the motor so that the rotational speed can be freely set. The up and down movement of the movable cap, the spin operation, and the dry air ejection operation are executed by the interlocking means.
[0026]
FIG. 7 is a process diagram of a cleaning method according to an embodiment of the present invention. When the wafers set in the magazine are set in the loader of the loader unit, the wafers are placed one by one on the cleaning stage and transferred to the next station. First transfer to the first cleaning station. The wafer is fixed with a chuck from the front and back. The cap comes down and spray cleaning 30 seconds. Next, the movable cap opens upward, and the wafer picked up by the chuck from the left and right is transferred to the second cleaning station. The wafer is fixed with a chuck from the front and back. The cap is lowered and sprayed for 30 seconds. Next, the cap opens upward, the wafer picked up from the left and right by the chuck is moved to the third cleaning station, the cleaning process is completed, and the wafer is transferred to the rinse station. Is done. In the rinsing process, first to second or third stations are provided from the pre-rinsing to the finishing rinsing. In this way, the single wafer cleaning process is executed by operating the transfer mechanism by the transfer control means at the tact time in which the wafers are simultaneously determined between the stations.
[0027]
After the final rinse, the wafer is transferred to a spin table, which is a drying station, fixed by vacuum suction means, and blown with dry air for 30 seconds at a spin speed of 3000 rpm to complete centrifugal dehydration (spin drying). . The high-speed spin eliminates the need for conventional hot air supply and saves fuel and space for hot air generating means. The wafer after spin drying is transferred to an unloader in front of it and taken out.
[0028]
【The invention's effect】
According to the present invention, since the cleaning speed has been improved, it can be manufactured in an installation space of about 70% of the conventional wafer conveyor apparatus. It is economical because it does not require generation means, and it collects and circulates cleaning fluid mist, consumes less detergent, has a lower operating cost, saves heat sources, contributes to resource and energy savings, and has great industrial value.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram according to an embodiment of the present invention.
FIG. 2 is an overall configuration diagram according to an embodiment of the present invention.
FIG. 3 is a structural diagram of a main part in an embodiment according to the present invention.
FIG. 4 is a structural diagram of a main part in an embodiment according to the present invention.
FIG. 5 is a structural diagram of a main part in an embodiment according to the present invention.
FIG. 6 is a structural diagram of a conventional apparatus.
FIG. 7 is a process chart in an embodiment according to the present invention.
FIG. 8 is a schematic view of cleaning of a conventional apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Loader unit 2 Cleaning process unit 3 Rinse process unit 4 Drying process unit 5 Unloader unit 11 Semiconductor wafer 14 Wafer conveyor 16 Injection nozzle 17 Carry-in port 18 Carry-out port 20 Exhaust duct 21 Cap shaft 22 Movable cap 23 Individual station 24 Dry air 25 Dry air 26 Dry Air Supply Pipe 27 Dry Air Supply Pipe 28 Spin Table 29 Injection Pressure Gauge

Claims (10)

An individual station having a movable cap covering the semiconductor wafer, a cleaning process unit, a rinsing process unit and a drying process unit containing one or more individual stations, and a tact determined in conjunction with the up and down movement of the cap. It includes a transfer control means and a transfer mechanism for transferring semiconductor wafers all at once, and a cleaning liquid tank, a rinsing liquid tank, and a liquid pump discharge adjusting means capable of adjusting the injection pressure and the amount of the rinsing liquid. A semiconductor wafer cleaning apparatus, wherein a liquid pump and a liquid spray pressure and a liquid volume are set to predetermined values for each individual station. A cap provided with an injection nozzle is provided at an individual station so that it covers the wafer set at the individual station. The cleaning apparatus according to claim 1, wherein the cleaning apparatus is connected to the liquid tank via a liquid pump via a liquid pump. One or a plurality of injection nozzles are provided for each station so as to be on the top of the semiconductor wafer, and the liquid injection angle θ from the nozzle with respect to the horizontal plane of the semiconductor wafer can be injected in a range of 10 ° ≦ θ ≦ 30 °. Item 3. The semiconductor wafer cleaning apparatus according to Item 1 or 2. The semiconductor wafer is moved laterally from the first station to the second station and then to the third station so that the wafers are transferred to the cleaning process, the rinsing process, and the drying process one after another at a determined tact time. The timing for picking up the semiconductor wafer from the left and right with the chuck and moving to the next process is within the period when the cap is open and the stage where the semiconductor wafer is to be placed is empty. 4. The semiconductor wafer cleaning apparatus according to claim 1, further comprising a transfer control means and a transfer mechanism for controlling the semiconductor wafer. 5. The semiconductor wafer cleaning apparatus according to claim 1, further comprising a fixing mechanism for fixing the semiconductor wafer transferred by the lateral movement by chucking from the front and rear sides of the semiconductor wafer. At the timing when the semiconductor wafer is transferred to the drying process, the lower surface of the wafer is fixed to a spin table having a vacuum suction means, and the wafer is rotated at a high speed to be centrifugally dried. After a predetermined time, the rotation is stopped. 6. The semiconductor wafer cleaning apparatus according to claim 1, further comprising rotation control means for stopping vacuum suction. Dry air is ejected from the opening of the dry air supply pipe onto the surface of the semiconductor wafer, and at the same time, the movable cap is driven up and down to cover the semiconductor wafer, and the dry air that opens to the back surface of the semiconductor wafer fixed to the spin table. 7. The semiconductor wafer cleaning apparatus according to claim 1, further comprising a drying unit in which the dry air supply pipe is connected to the dry air generation unit by an air guide tube so that dry air is jetted from the opening of the supply pipe to the back surface of the wafer. . Drying is performed such that dry air is jetted from the opening of a dry air supply pipe to the front and back surfaces of the semiconductor wafer vacuum-sucked on the spin table, and the spin table is spun dry by rotating the spin table at a high speed. After the movable cap provided with the dry air supply pipe is covered with the semiconductor wafer, the drying process unit is spin-dried by dry air ejection and high-speed rotation, and after the dry air ejection and high-speed rotation is completed, the movable cap is 8. A semiconductor wafer cleaning apparatus according to claim 1, further comprising a cap moving above the wafer and an interlocking means of spin and air. An individual station having a movable cap covering the semiconductor wafer, a cleaning process unit, a rinse process unit and a drying process unit in which one or more individual stations are accommodated, and a tact determined in conjunction with the opening and closing operation of the cap A means for placing a silicon wafer contained in a magazine on a cleaning stage in a cleaning device comprising a transfer control means and a transfer mechanism for transferring semiconductor wafers simultaneously in time, and comprising a cleaning liquid tank and a rinsing liquid tank. A loader unit was connected to a position close to the cleaning process unit, and a drying process unit comprising a drying means for spin drying by rotating the spin table at a high speed was connected to a rear side position of the unloader unit as an outlet. 9. A semiconductor wafer cleaning apparatus according to claim 1. The semiconductor wafers are transferred from the cleaning stage to the cleaning process, rinse process, and drying process one after another at a determined tact time, and the composite electrolytic ionic water or the detergent water is spray-cleaned at a predetermined spray angle with respect to the semiconductor wafer horizontal plane. A semiconductor wafer cleaning process, a cleaning process including pre-rinsing with ion exchange water or composite electrolytic ionic water and finishing rinsing, a spin drying process including centrifugal dehydration by spin table high-speed rotation and dry air spraying Method.

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