JP2010034211A - Semiconductor wafer, and cleaning device and cleaning method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method and a cleaning device for a semiconductor wafer, capable of preventing particles or metal impurities contained in a cleaning liquid from sticking to the surface of a semiconductor wafer, and capable of preventing them from being mixed with a rinsing liquid held in a rinsing bath. <P>SOLUTION: The cleaning device 1 includes a cleaning bath 2 in which a first cleaning liquid 6 for cleaning a semiconductor wafer 8 is stored, a rinsing bath 3 in which a rinsing liquid 7 for rinsing the semiconductor wafer 8 that has been cleaned in the cleaning bath 2 is stored, a transportation device 4 which transports the semiconductor wafer 8 from the cleaning bath 2 to the rinsing bath 3, and a spray nozzle 5 which jets a second cleaning liquid 13 at the temperature lower than that of the first cleaning liquid 6 against the semiconductor wafer 8 transported by the transportation device 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor wafer, a cleaning apparatus thereof, and a cleaning method thereof.

  As a technique for performing a cleaning process on a semiconductor wafer, a multi-tank immersion cleaning process is known (for example, see Patent Document 1). In this cleaning process, a plurality of wafers are stored in a dedicated cleaning cassette, and the cleaning cassette in which the wafers are stored is immersed in a cleaning tank or a rinsing tank in a predetermined order by a transfer robot, and a predetermined cleaning process is performed. Is to do.

A technique is also known in which a wafer is directly gripped and transferred by a transfer robot without using a cleaning cassette, and a cleaning process is performed.
JP-A-6-163492

  However, when the semiconductor wafer cleaned in the cleaning tank in which the cleaning liquid (for example, SC-1 liquid) is stored is transported from the cleaning tank and transferred to the rinsing tank, the cleaning liquid attached to the surface of the semiconductor wafer is dried. There is a problem that particles and metal impurities contained in the wafer adhere to the surface of the semiconductor wafer.

  Further, when the semiconductor wafer is transported, even if the cleaning liquid adhering to the surface of the semiconductor wafer is not dried, particles and metal impurities contained in the cleaning liquid are mixed into the rinsing liquid stored in the rinsing tank and are rinsed. There was a problem of contaminating the liquid.

  The present invention has been made in view of the above-described problems, and prevents particles and metal impurities contained in the cleaning liquid from adhering to the surface of the semiconductor wafer, and the particles and metal impurities contained in the cleaning liquid are rinse baths. It is an object of the present invention to provide a semiconductor wafer cleaning apparatus and a cleaning method thereof that can prevent mixing in the rinsing liquid stored in the semiconductor wafer.

  (1) A semiconductor wafer cleaning apparatus of the present invention includes a cleaning tank storing a first cleaning liquid for cleaning a semiconductor wafer, and a rinsing liquid storing a rinsing liquid for rinsing the semiconductor wafer cleaned in the cleaning tank. A tank, a transport device for unloading the semiconductor wafer from the cleaning bath and transporting the semiconductor wafer to the rinsing bath, and a first temperature lower than the temperature of the first cleaning liquid in the semiconductor wafer transported by the transport device. And a spray nozzle for spraying the cleaning liquid.

  (2) Moreover, the said conveyance apparatus is provided with the holding | maintenance part holding the said semiconductor wafer, and the conveyance part which conveys the said holding | maintenance part, When the said spray nozzle faces the said semiconductor wafer, It is preferable to be located between the semiconductor wafer.

  (3) Moreover, it is preferable that the temperature of the said 1st washing | cleaning liquid is 50-90 degreeC, the temperature of the said rinsing liquid is 20-26 degreeC, and the temperature of the said 2nd washing | cleaning liquid is 20-26 degreeC. .

  (4) The semiconductor wafer cleaning method of the present invention includes a cleaning tank storing a first cleaning liquid for cleaning a semiconductor wafer, and a rinsing liquid storing a rinsing liquid for rinsing the semiconductor wafer cleaned in the cleaning tank. Semiconductor wafer cleaning comprising: a tank; a transfer device for unloading the semiconductor wafer from the cleaning tank and transferring it to the rinsing tank; and a spray nozzle for spraying a second cleaning liquid onto the semiconductor wafer transferred by the transfer device A method for cleaning a semiconductor wafer using an apparatus, the first cleaning step for cleaning the semiconductor wafer in the cleaning tank, and the cleaning of the semiconductor wafer by the transfer device after the first cleaning step. When transporting from the tank to the rinsing tank, the second cleaning liquid having a temperature lower than the temperature of the first cleaning liquid is transferred to the semiconductor by the spray nozzle. A second cleaning step of blowing in Eha, characterized in that it comprises a.

  (5) Moreover, it is preferable that the temperature of the said 1st washing | cleaning liquid is 50-90 degreeC, the temperature of the said rinsing liquid is 20-26 degreeC, and the temperature of the said 2nd washing | cleaning liquid is 20-26 degreeC. .

  (6) The semiconductor wafer of the present invention is obtained by being cleaned by the semiconductor wafer cleaning method.

  According to the semiconductor wafer cleaning apparatus and the cleaning method of the present invention, particles and metal impurities contained in the cleaning liquid are prevented from adhering to the surface of the semiconductor wafer, and the particles and metal impurities contained in the cleaning liquid are stored in the rinsing tank. It is possible to prevent contamination in the rinsing liquid.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a semiconductor wafer cleaning apparatus and a cleaning method of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an outline of a cleaning apparatus 1 according to an embodiment of the present invention. FIG. 2 is a side view showing configurations of the cleaning tank 2 and the transfer device 4. As shown in FIGS. 1 and 2, the cleaning device 1 includes a cleaning tank 2, a rinsing tank 3, a transport device 4, and a spray nozzle 5.

  The cleaning tank 2 stores a first cleaning liquid 6 for cleaning the semiconductor wafer 8. The first cleaning liquid 6 is, for example, SC-1 liquid (a mixed liquid of ammonia water, hydrogen peroxide water, and pure water). The SC-1 solution is used to remove particles and impurities attached to the surface of the semiconductor wafer 8. When the 1st washing | cleaning liquid 6 is SC-1 liquid, the temperature has preferable 50-90 degreeC. This is because, when the temperature is lower than 50 ° C., the cleaning speed for cleaning the semiconductor wafer 8 becomes slow, and the cleaning efficiency deteriorates. Further, when the temperature exceeds 90 ° C., surface roughness is likely to occur on the surface of the semiconductor wafer 8.

  In the rinsing tank 3, a rinsing liquid 7 for rinsing the semiconductor wafer 8 cleaned in the cleaning tank 2 is stored. The rinsing liquid 7 is pure water, for example. The semiconductor wafer 8 is immersed in the rinsing liquid 7 so that the first cleaning liquid 6 attached in the cleaning tank 2 is removed. When the rinsing liquid 7 is pure water, the temperature is preferably 20 to 26 ° C.

  The transfer device 4 unloads the semiconductor wafer 8 from the cleaning tank 2 and transfers it to the rinse tank 3. The transfer device 4 includes a robot arm (holding unit) 10, a transfer robot (transfer unit) 11, and a rail 12. The robot arm 10 holds a cleaning cassette 9 in which the semiconductor wafer 8 is stored. The transfer robot 11 transfers the robot arm 10 from the cleaning tank 2 to the rinsing tank 3. The transfer robot 11 transfers the cleaning cassette 9 in which the semiconductor wafer 8 is stored along the transfer paths L1, L2, and L3. The rail 12 is located above the liquid surfaces of the first cleaning liquid 6 and the rinsing liquid 7 and is provided along the horizontal direction. The transfer robot 11 moves along the rail 12.

  The conveyance path L <b> 1 is a path for holding the cleaning cassette 9 by the conveyance device 4 and carrying it into the cleaning tank 2. The conveyance path L <b> 2 is a path for holding the cleaning cassette 9 by the conveyance device 4, carrying it out of the cleaning tank 2, and carrying it into the rinsing tank 3. The conveyance path L <b> 3 is a path for holding the cleaning cassette 9 by the conveyance device 4 and carrying it out of the rinsing tank 3.

  In the cleaning apparatus 1 of this embodiment, the semiconductor wafer 8 is stored in the cleaning cassette 9 and cleaned. However, the present invention is not limited to this, and the semiconductor wafer 8 may be directly held by the robot arm 10 and transferred. . The semiconductor wafer 8 can be a silicon wafer, a gallium arsenide wafer, or the like. The diameter of the semiconductor wafer 8 is not particularly limited, and is, for example, 200 mm, 300 mm, or 450 mm.

A semiconductor wafer 8 is stored in the cleaning cassette 9. On the side surface of the cleaning cassette 9, a handle portion 9 a for holding the cleaning cassette 9 by the robot arm 10 is provided.
The cleaning cassette 9 containing the semiconductor wafer 8 is held by the robot arm 10 and is carried into the cleaning tank 2 along the transfer path L1 shown in FIG. The cleaning cassette 9 is placed on a cassette mounting table 14 provided at the bottom of the cleaning tank 2. Further, the cleaning cassette 9 after cleaning is held by the robot arm 10 and carried out of the cleaning tank 2, and is transferred to the rinsing tank 3 along the transfer path L2 shown in FIG.

The spray nozzle 5 sprays the second cleaning liquid 13 having a lower temperature than the temperature of the first cleaning liquid 6 onto the semiconductor wafer 8 transported by the transport device 4. The spray nozzle 5 is provided in the vicinity of the conveyance path L2. Details of the spray nozzle 5 will be described later. Further, pure water is used as the second cleaning liquid 13. The temperature difference between the first cleaning liquid 6 and the second cleaning liquid 13 is preferably 24 to 70 ° C.
In this embodiment, pure water is used as the second cleaning liquid 13, but the present invention is not limited to this, and other cleaning liquid (for example, SC-1 liquid) may be used.

As shown in FIG. 2, the robot arm 10 includes an arm unit 10a and a drive unit 10b.
The arm portion 10a is a portion that holds the handle portion 9a of the cleaning cassette 9 during transportation.
The drive unit 10b is configured to be extendable and contractable in the vertical direction. Accordingly, the cleaning cassette 9 and the arm portion 10a can approach or separate from the cleaning tank 2 or the rinsing tank 3.

  FIG. 3 is a side view showing details of the spray nozzle 5. As shown in FIG. 3, the spray nozzle 5 is positioned between the transfer robot 11 and the semiconductor wafer 8 when facing the semiconductor wafer 8. The position where the spray nozzle 5 is provided is a position at a sufficient distance from the cleaning tank 2 and the rinsing tank 3 in order to prevent mixing of pure water sprayed from the spray nozzle 5 into the cleaning tank 2 and the rinsing tank 3. Moreover, it is preferable that the space | interval of the edge part by the side of the washing cassette 9 of the washing tank 2 and the edge part by the side of the washing tank 2 of the washing cassette 9 is 150 mm or more.

  The second cleaning liquid 13 is sprayed so that the semiconductor wafer 8 and the cleaning cassette 9 are cleaned uniformly. The time from when the cleaning cassette 9 is carried out of the cleaning tank 2 by the transport device 4 to when the second cleaning liquid 13 is sprayed by the spray nozzle 5 is preferably within one second. The second cleaning liquid 13 is preferably sprayed for 4 seconds or more at a flow rate of 4 to 10 L / min. The cleaning cassette 9 is preferably carried into the rinsing tank 3 by the transfer robot 11 within 10 seconds after the process of spraying the second cleaning liquid 13 by the spray nozzle 5 is completed.

  Thus, according to the cleaning apparatus 1 of the present embodiment, the spray nozzle 5 that sprays the second cleaning liquid 13 having a temperature lower than the temperature of the first cleaning liquid 6 onto the semiconductor wafer 8 transferred by the transfer apparatus 4 is provided. Therefore, the semiconductor wafer 8 can be carried into the rinsing tank 3 with particles and metal impurities removed from the surface of the semiconductor wafer 8. Further, it is possible to prevent particles and metal impurities contained in the first cleaning liquid 6 from entering the rinsing liquid 7 of the rinsing tank 3.

  Further, according to the cleaning apparatus 1 of the present embodiment, the semiconductor wafer 8 cleaned by the first cleaning liquid 6 is cleaned by spraying the second cleaning liquid 13 onto the semiconductor wafer 8, and the semiconductor wafer 8 is cooled. It can be carried out.

  Next, an embodiment of the semiconductor wafer cleaning method of the present invention will be described. The semiconductor wafer cleaning method of this embodiment uses the cleaning apparatus 1 described above. The semiconductor wafer cleaning method according to the present embodiment includes a first cleaning process for cleaning the semiconductor wafer 8 with the first cleaning liquid 6, and after the first cleaning process, the semiconductor wafer 8 is cleaned in the cleaning tank 2 by the transfer device 4. A second cleaning step in which a second cleaning solution 13 having a temperature lower than the temperature of the first cleaning solution 6 is sprayed onto the semiconductor wafer 8 by the spray nozzle 5 and the rinsing solution 7. A rinsing process for cleaning the semiconductor wafer 8.

(First cleaning step)
The semiconductor wafer 8 is cleaned with the first cleaning liquid 6 in the cleaning tank 2. As described above, the SC-1 liquid or the like is used for the first cleaning liquid 6. The temperature of the first cleaning liquid 6 is preferably 50 to 90 ° C.

(Second cleaning step)
The semiconductor wafer 8 that has undergone the first cleaning step is transferred from the cleaning tank 2 to the rinsing tank 3 by the transfer device 4. At this time, the semiconductor wafer 8 is cleaned using the second cleaning liquid 13 by the spray nozzle 5 provided in the transport path L2 (see FIG. 1). The 2nd washing | cleaning liquid 13 is temperature lower than the temperature of the 1st washing | cleaning liquid 6, and 20-26 degreeC is preferable.

(Rinsing process)
The semiconductor wafer 8 that has undergone the second cleaning step is carried into the rinsing tank 3 by the transfer device 4 and cleaned by the rinsing liquid 7. As described above, pure water or the like is used for the rinsing liquid 7. The temperature of the rinsing liquid 7 is preferably 20 to 26 ° C.

  Next, the present invention will be described in more detail using examples. In addition, this Example does not limit the scope of the present invention.

  The cleaning effect of particles and metal impurities by the spray nozzle 5 according to the present invention will be described using examples and comparative examples.

[Example]
Twenty-five silicon wafers having a diameter of 200 mm were used as the semiconductor wafer 8, and this silicon wafer was stored in a cleaning cassette 9 for cleaning. Further, SC-1 solution having a temperature of 80 ° C. was used as the first cleaning solution 6, and pure water having a temperature of 24 to 26 ° C. was used as the rinsing solution 7. Further, pure water having a temperature of 23 ± 2 ° C. was used as the second cleaning liquid 13.

[Comparative example]
The comparative example is different from the example in that the cleaning process by the spray nozzle 5 is excluded, and the other conditions are the same as the example.

  FIG. 4 is a graph showing the size and the number of particles adhering to the surface of the silicon wafer. The horizontal axis is the particle size, and the vertical axis is the number of particles. The particle size was evaluated at three levels of 0.1 μm or more, 0.2 μm or more, and 0.3 μm or more. The number of particles is an average value of the number of particles attached to each of 25 silicon wafers in units of wafers.

  In each example, the number of particles was smaller than that in the comparative example at any level. In particular, in the case of particles of 0.1 μm or more, the number of particles was significantly smaller than that in the comparative example.

FIG. 5 is a graph showing the concentration of metal impurities attached to the surface of the silicon wafer. The metal impurity was Fe, and the concentration (atomos / cm ² ) of the metal impurity was measured by inductively coupled plasma mass spectrometry (ICP-MS) (Inductively Coupled Plasma Mass Spectroscopy).
As shown in FIG. 5, the metal impurity concentration in the example was significantly reduced as compared with the comparative example.

1 is a side view showing an outline of a cleaning apparatus 1 according to an embodiment of the present invention. It is a side view which shows the structure of the washing tank 2 and the conveying apparatus 4. FIG. 4 is a side view showing details of the spray nozzle 5. FIG. It is the graph showing the size of the particle adhering to the surface of a silicon wafer, and the number of particles. It is a graph showing the density | concentration of the metal impurity adhering to the surface of a silicon wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cleaning apparatus 2 Cleaning tank 3 Rinse tank 4 Conveyance apparatus 5 Spray nozzle 6 1st cleaning liquid 7 Rinsing liquid 8 Semiconductor wafer 9 Cleaning cassette 10 Robot arm (holding part)
11 Conveying robot (conveying unit)
12 rail 13 second cleaning liquid

Claims (6)

A cleaning tank in which a first cleaning liquid for cleaning the semiconductor wafer is stored;
A rinsing tank in which a rinsing liquid for rinsing the semiconductor wafer cleaned in the cleaning tank is stored;
A transporting device for transporting the semiconductor wafer out of the cleaning tank and transporting it to the rinsing tank;
A semiconductor wafer cleaning apparatus, comprising: a spray nozzle that sprays a second cleaning liquid having a temperature lower than that of the first cleaning liquid onto the semiconductor wafer transported by the transport apparatus. The transfer device includes a holding unit that holds the semiconductor wafer, and a transfer unit that transfers the holding unit,
2. The semiconductor wafer cleaning apparatus according to claim 1, wherein the spray nozzle is positioned between the transfer unit and the semiconductor wafer when facing the semiconductor wafer. 3.   The temperature of the first cleaning liquid is 50 to 90 ° C, the temperature of the rinsing liquid is 20 to 26 ° C, and the temperature of the second cleaning liquid is 20 to 26 ° C. The semiconductor wafer cleaning apparatus described in 1. A cleaning tank storing a first cleaning liquid for cleaning a semiconductor wafer, a rinsing tank storing a rinsing liquid for rinsing the semiconductor wafer cleaned in the cleaning tank, and unloading the semiconductor wafer from the cleaning tank A semiconductor wafer cleaning method using a semiconductor wafer cleaning apparatus, comprising: a transport apparatus that transports the rinsing tank to the rinse tank; and a spray nozzle that sprays a second cleaning liquid onto the semiconductor wafer transported by the transport apparatus,
A first cleaning step of cleaning the semiconductor wafer in the cleaning tank;
After passing through the first cleaning step, when the semiconductor wafer is transferred from the cleaning tank to the rinsing tank by the transfer device, the spray nozzle causes the temperature of the first cleaning liquid to be lower than that of the first cleaning liquid. And a second cleaning step of spraying a second cleaning liquid onto the semiconductor wafer.   The temperature of the first cleaning liquid is 50-90 ° C, the temperature of the rinsing liquid is 20-26 ° C, and the temperature of the second cleaning liquid is 20-26 ° C. A method for cleaning a semiconductor wafer as described in 1.   A semiconductor wafer cleaned by the semiconductor wafer cleaning method according to claim 4.

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