JPH11233473A - Method and device for cleaning semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage caused by the heat generated by discharge of static electricity on the substrate such as a semiconductor wafer to achieve a lower defect rate. SOLUTION: A semiconductor wafer 100 is held by a rotating vacuum chuck table 10. A cleaning solution 32 in a cleaning solution bath 30 is supplied onto the semiconductor wafer 100 from the end of a nozzle 20. The cleaning solution 32 is first supplied onto the non-circuit part of the semiconductor wafer 100 to discharge the substrate. Then, the solution is supplied to the circuit part in the center of the semiconductor wafer 100 to clean it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor cleaning apparatus and method, and more particularly to a semiconductor cleaning apparatus and method for cleaning a semiconductor by dropping a cleaning liquid on a rotating semiconductor integrated circuit.

[0002]

2. Description of the Related Art In a conventional semiconductor cleaning apparatus, a semiconductor wafer is supported by a suction table, the semiconductor wafer is rotated at a low speed, and a cleaning liquid is dropped on the rotating semiconductor wafer to clean the semiconductor wafer. I have to. After cleaning the semiconductor wafer, the semiconductor wafer is rotated at a high speed to shake off a cleaning liquid adhering to the semiconductor wafer and to dry it.

When the semiconductor wafer is dried, static electricity is charged on the suction table due to friction between the suction table and the air that rotates at a high speed.
The static electricity remaining on the suction table also charges the semiconductor wafer. When the cleaning liquid is dropped on the semiconductor wafer in this state, the electric charge of the semiconductor wafer escapes through the cleaning liquid,
There has been a problem that a discharge is generated via air and the semiconductor surface is damaged by heat.

A method for preventing the influence of static electricity charged on a semiconductor wafer is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-131046.
As described in Japanese Patent Application Laid-Open Publication No. H10-209, there is known a method of introducing ions generated from an ion generator to the surface of a semiconductor wafer to eliminate static electricity.

[0005]

However, in the method using an ion generator, as described in Japanese Patent Application Laid-Open No. Hei 3-131026, the ion generator has a problem that the electric charge sputters the electrode material. Are generated as foreign matter. Therefore, the foreign matter generated by the ion generator adheres to the surface of the semiconductor wafer, which causes a problem that the yield of manufactured semiconductor products is reduced.

An object of the present invention is to provide a semiconductor cleaning apparatus and method which prevent damage due to heat generated by the discharge of static electricity charged on a substrate such as a semiconductor wafer and improve the yield.

[0007]

(1) In order to achieve the above object, the present invention provides a supporting means for supporting a substrate on which a semiconductor integrated circuit portion is formed, and a supporting means for supporting the substrate on which the semiconductor integrated circuit is formed. A cleaning liquid supply unit for supplying a cleaning liquid, wherein the cleaning liquid supply unit supplies the cleaning liquid to a non-circuit portion where the semiconductor integrated circuit portion is not formed on a substrate supported by the support portion. rear,
The cleaning liquid is supplied to the semiconductor integrated circuit section. With such a configuration, the electric charge charged on the substrate is discharged by supplying the cleaning liquid to the non-circuit portion, and thereafter, the cleaning liquid is supplied to the circuit portion for cleaning.
In addition to preventing damage due to heat generated by the discharge of static electricity charged on the substrate, generation of foreign matter can be prevented, and the yield can be improved.

(2) In order to achieve the above object, according to the present invention, a cleaning liquid is supplied onto a substrate supported by a support means,
In the semiconductor cleaning method for cleaning the substrate, after supplying the cleaning liquid to a non-circuit portion on which the semiconductor integrated circuit portion is not formed on the substrate supported by the support means, the cleaning liquid is supplied to the semiconductor integrated circuit portion. It is intended to be supplied. According to such a method, the electric charge charged on the substrate is discharged by supplying the cleaning liquid to the non-circuit portion, and thereafter, the cleaning liquid is supplied to the circuit portion for cleaning, thereby being generated by the discharge of the static electricity charged on the substrate. In addition to preventing damage due to heat, the generation of foreign matter can be prevented, and the yield can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor cleaning apparatus and method according to one embodiment of the present invention will be described below with reference to FIGS. First, the configuration of the semiconductor cleaning apparatus according to the present embodiment will be explained with reference to FIG. FIG. 1 is a block diagram showing a configuration of a semiconductor cleaning apparatus according to one embodiment of the present invention.

The suction table 10 is connected to a motor 14 via a shaft 12, and can be rotated at a low speed or a high speed by the motor 14. The suction table 10
It is formed of a non-conductive material such as a fluororesin. By using a fluorine resin for the suction table 10, generation of dust from the suction table 10 is reduced. The number of rotations of the suction table 10 is, for example, 100 rpm at low speed rotation, and 10000 rpm at high speed rotation.
And

The shaft 1 fixed to the suction table 10
2 has a hollow shape, and its end is connected to a pump 18 via an electromagnetic valve 16. Therefore, after the semiconductor wafer 100 is placed on the suction table 10, the semiconductor wafer 100 is sucked and fixedly supported by the pump 18 by operating the pump 18.

The nozzle 20 is fixed to an end of an arm 22 and is rotatable by a motor 24. The rotation operation of the nozzle 20 will be described later with reference to FIG.
The end of the nozzle 20 is connected to a pump 28 via a pipe P and an electromagnetic valve 26. The pump 28 is connected to the cleaning liquid layer 30 via a pipe P. A cleaning liquid 32 is contained in the cleaning liquid tank 30. As the cleaning liquid 32, for example, acetic acid (CH ₃ COOH)
(2.96 ± 0.3 wt%) and ammonium acetate (C
H ₃ COONH ₄ ) (7.24 ± 0.9 wt%) is used in distilled water. The pH of this cleaning solution is 5.1 ± 0.3, and is a weakly acidic cleaning solution. By operating the pump 28, the cleaning liquid 32 in the cleaning liquid tank 30 is supplied to the pipe P
Flows out of the tip of the nozzle 20 through the nozzle. The cleaning liquid flowing out of the nozzle 20 is supplied onto the semiconductor wafer 100 supported on the suction table 10. The flow rate of the cleaning liquid 32 is, for example, 200 ml / min, and the outflow time is, for example, 60 to 120 seconds.

On the outer periphery of the semiconductor wafer 100 supported by the suction table 10, a cylindrical splash guard 4 is provided.
0 is arranged. The splash guard 40 is attached to the linear rail 42. Linear rail 42
Is driven by a motor 44. By operating the motor 44, the upper end of the splash guard 40
As shown in the figure, it is possible to move from a position above the semiconductor wafer 100 to a position below the state shown in the figure. When the upper end of the splash guard 40 is positioned above the semiconductor wafer 100, the cleaning liquid supplied to the upper surface of the rotating semiconductor wafer 100 is prevented from being scattered. The suction table 10 and the splash guard 40 are arranged in a waste liquid cup 46, and the cleaning liquid supplied to the upper surface of the semiconductor wafer 100 is received by the waste liquid cup 46 and is discarded in a waste liquid tank (not shown).

The control device 50 includes driver circuits 60 and 6
2 and 64 and power supplies 70 and 72, and controls the entire semiconductor cleaning apparatus according to the present embodiment. The driver circuit 60 controls low-speed rotation, high-speed rotation, and rotation stop of the motor 14 based on a control signal from the control device 50. The driver circuit 62 controls forward / reverse rotation and rotation stop of the motor 24 based on a control signal from the control device 50. The driver circuit 64 controls forward / reverse rotation and rotation stop of the motor 44 based on a control signal from the control device 50. The power supply 70 is turned on / off based on a control signal from the control device 50 and opens and closes the electromagnetic valve 16. The power supply 72 is turned on / off based on a control signal from the control device 50 and opens and closes the electromagnetic valve 28.

Next, the rotation operation of the nozzle used in the semiconductor cleaning apparatus according to the present embodiment will be explained with reference to FIG. FIG. 2 is an explanatory diagram of the rotation operation of the nozzle used in the semiconductor cleaning device according to one embodiment of the present invention.

Inside the cylindrical splash guard 40, a semiconductor wafer 10 supported by suction on a suction table is provided.
0 is arranged. The semiconductor wafer 100 has a disk shape. On the upper surface thereof, there are formed a circuit portion 110 on which a plurality of semiconductor chips 112 are formed and a non-circuit portion 120 on the periphery of the circuit portion 110 on which no semiconductor chips are formed. I have. The outer diameter size of the semiconductor wafer 100 is, for example, 8 inches, and the outer diameter size of the semiconductor chip 112 is 6 ×
12 mm ² . A distance L between the outermost periphery of the circuit portion 110 on which the semiconductor chip 112 is formed and the outer periphery of the semiconductor wafer 100 is, for example, at least 5 mm, and this region is provided as the non-circuit portion 120.

As shown, the arm 22 holding the nozzle 20 is rotatable around the rotation center O from the position of the arm 22A to the position of the arm 22C within an angle θ. The position of the arm 22A is a position where the tip of the nozzle 20 is located outside the splash guard 40. The position of the arm 22C is a position where the tip of the nozzle 20 is located at the center of the semiconductor wafer 100. The position of the arm 22 </ b> B is a position where the tip of the nozzle 20 is located inside the splash guard 40 and on the outer peripheral side of the semiconductor wafer 100.

In this embodiment, when the arm 22 rotates and moves from the arm 22A to the position of the arm 22B, the cleaning liquid starts to flow from the tip of the nozzle 20. The cleaning liquid is moved to the position of the arm 22C while the cleaning liquid flows out from the tip of the nozzle 20, and the semiconductor wafer 1 is moved.
The cleaning liquid is supplied to the central part of 00. At this time, the semiconductor wafer 100 is rotating at a low speed.

Next, the method for cleaning the semiconductor wafer using the semiconductor cleaning apparatus according to the present embodiment will be explained with reference to FIGS.

First, as shown in FIG. 1, a semiconductor wafer 100 on which a circuit portion is formed is set on a non-conductive suction table 10. The control device 50 outputs a control signal to the power supply 70, turns on the switch of the power supply 70, and opens the electromagnetic valve 16. Since the pump 18 is operating, when the electromagnetic valve 16 is opened, air is taken in from the air suction port on the contact surface of the suction table 10 with the semiconductor wafer 100, and the suction table 10 → the shaft 12 → the motor 14 → Electromagnetic valve 16 → Suction pump 18
Then, the semiconductor wafer 100 is suction-fixed to the suction table 10.

Next, the control device 50 outputs a control signal for driving the motor 24 to the driver circuit 62, and the driver circuit 62 drives the motor 24 based on the control signal. When the motor 24 is driven, the arm 22 rotates,
The nozzle 20 attached to the arm 22 moves to a position inside the splash guard 40 and on the outer periphery of the semiconductor wafer 100. That is, as described in FIG. 2, the nozzle 20 is moved to the position of the illustrated arm 22 </ b> B, that is, the position where the tip of the nozzle 20 is inside the splash guard 40 and located on the outer peripheral side of the semiconductor wafer 100. .

Next, the control device 50 outputs a control signal for driving the motor 44 to the driver circuit 64, and the driver circuit 64 drives the motor 44 based on the control signal. By driving the motor 44, the upper end of the splash guard 40 attached to the linear rail 42 moves above the semiconductor wafer 100.

Next, the control device 50 outputs a control signal for driving the motor 14 to the driver circuit 60,
Drive. The suction table 1 is driven by driving the motor 14.
0 rotates the semiconductor wafer 100 at a low speed.
The rotation speed of the semiconductor wafer 100 at this time is, for example, 1
00 rpm.

Next, the control device 50 outputs a control signal for opening and closing the electromagnetic valve 26 to the power supply 72, turns on the switch of the power supply 72, and opens the electromagnetic valve 26. When the electromagnetic valve 26 is opened, the cleaning liquid 32 in the cleaning liquid tank 30 flows out of the tip of the nozzle 20 through the pipe P.

Next, the control device 50 outputs a control signal for driving the motor 24 to the driver circuit 62, and the driver circuit 62 drives the motor 24 based on the control signal. When the motor 24 is driven, the arm 22 rotates,
The nozzle 20 attached to the arm 22 moves to a position above the center of the semiconductor wafer 100. That is, as described in FIG. 2, from the position of the illustrated arm 22B,
The nozzle 20 is moved to the position of the illustrated arm 22C.

At this time, since the cleaning liquid 32 flows out from the tip of the nozzle 20, the cleaning liquid 32 is first supplied to the non-circuit portion 120 of the semiconductor wafer 100 rotating at a low speed. The electric charge charged on the semiconductor wafer 100 is:
Discharge occurs in the cleaning solution. The non-circuit portion 120 of the semiconductor wafer 100 is heated by the electrostatic discharge, but the non-circuit portion 1 is heated.
Since no circuit portion such as a semiconductor chip is formed on the circuit portion 20, the circuit portion is not damaged. The nozzle 20 moves gradually from the non-circuit portion 120 on the outer peripheral side of the semiconductor wafer 100 toward the center while the cleaning liquid 32 flows out, and the cleaning liquid is supplied to the circuit portion 110. Since the charged electric charge is discharged, the circuit portion 110 is not damaged by the discharge. The nozzle 20 is the semiconductor wafer 1
By supplying the cleaning liquid 32 onto the semiconductor wafer 100 which is rotating at a low speed, located just above the center position of the semiconductor wafer 100, the cleaning liquid is diffused to the outer peripheral side by the centrifugal force of the rotating semiconductor wafer 100, and The surface of the wafer 100 is cleaned. The washing liquid scattered by the centrifugal force is prevented from being scattered by the splash guard 40, and the dropped washing liquid is stored in the waste liquid cup 46 and then discarded in the waste liquid tank.

After the cleaning liquid 32 is sufficiently dropped on the semiconductor wafer 100 and the cleaning is completed, the control device 50 outputs a control signal for opening and closing the electromagnetic valve 26 to the power supply 72, and
The switch 2 is turned off, and the electromagnetic valve 26 is closed.

Next, the control device 50 outputs a control signal for driving the motor 24 to the driver circuit 62. The driver circuit 62 drives the motor 24 based on the control signal.
The nozzle 20 attached to the arm 22 is connected to the semiconductor wafer 1
00 Avoid from above. That is, the arm 22C shown in FIG.
The arm 22 is moved from the position to the position of the arm 22A.

Next, the control device 50 outputs a control signal for driving the motor 14 to the driver circuit 60. The driver circuit 60 drives the motor 14 based on the control signal, and drives the semiconductor wafer 100 at high speed. By rotating, the cleaning liquid 32 attached to the semiconductor wafer 100 is shaken off. The rotation speed of the semiconductor wafer at this time is, for example, 10,000 rpm.
m, and the suction table 10 is charged by friction with air to perform such high-speed rotation. Therefore, at the time of cleaning the next semiconductor wafer, the installed semiconductor wafer is charged.

Cleaning liquid 32 adhered to semiconductor wafer 100
Is sufficiently shaken, the control device 50 outputs a control signal for driving the motor 14 to the driver circuit 60, and the driver circuit 60 stops the motor 14 based on the control signal.

Next, the control device 50 outputs a control signal for driving the motor 44 to the driver circuit 64. The driver circuit 64 drives the motor 44, and the upper end of the splash guard 40 attached to the linear rail 42. Is moved below the semiconductor wafer 100.

Next, the control device 50 outputs a control signal for the power supply 70, turns off the switch of the power supply 70, and closes the electromagnetic valve 16. As a result, the semiconductor wafer 100 can be removed from the suction table 10, so that the semiconductor wafer 100 is removed from the suction table 10.

With the above steps, the cleaning of the semiconductor wafer is completed. Next, the uncleaned semiconductor wafer 100 is set on the suction table 10, and the above steps are repeated to perform cleaning.

As described above, in this embodiment, the cleaning liquid is first supplied to the non-circuit portion 120 on the outer peripheral side of the semiconductor wafer 100, so that the electric charge of the semiconductor wafer 100 is Is discharged to the cleaning liquid at the
The semiconductor chip is not damaged by the discharge, and the yield of the semiconductor chip can be improved.

In the above description, the nozzle 20 is located inside the splash guard 40 and on the semiconductor wafer 1.
After the cleaning liquid 32 starts flowing out after being positioned at a position outside of the position 00, the nozzle 20 is moved toward the center of the semiconductor wafer 100.
Even if the cleaning liquid 32 is started to flow after positioning on the non-circuit portion 120 on the outer peripheral side of the semiconductor wafer 100, the discharge can be performed first in the non-circuit portion 120. However, the method of the above embodiment does not require higher positioning accuracy.

The non-circuit portion 12 of the semiconductor wafer 100
After the cleaning liquid 32 is supplied to the nozzle 20 and discharged, the cleaning liquid is moved toward the center of the semiconductor wafer 100 while flowing out of the nozzle 20. After stopping the outflow of the cleaning liquid and moving the nozzle to the center of the semiconductor wafer 100,
Cleaning may be started by starting the outflow of the cleaning liquid.

In the above description, the case of cleaning a semiconductor wafer has been described. However, the present invention can be similarly applied to cleaning of semiconductor chips cut from a semiconductor wafer. That is, since the semiconductor chip also has a non-circuit portion on the outer peripheral side of the circuit portion, even when cleaning the semiconductor chip, first, a cleaning liquid is supplied to the non-circuit portion to discharge the charged electric charge, and thereafter, Alternatively, a cleaning liquid can be supplied to the circuit section to clean the semiconductor chip.

Next, the effect of improving the yield when the semiconductor cleaning method according to the present embodiment is used will be described with reference to FIGS. FIG. 3 shows the yield distribution when the semiconductor wafer is cleaned using the semiconductor cleaning method according to the present embodiment. In the figure, each rectangle corresponds to an individual semiconductor chip formed on a semiconductor wafer, and the height of each rectangle represents the yield.

As is clear from FIG. 3, the yield is reduced on the outer peripheral side of the semiconductor wafer, but inside the semiconductor wafer, the yield is as high as 80 to 100%.
In particular, it should be noted that the yield near the center of the semiconductor wafer shows the same high yield of 80 to 100% as that around the semiconductor wafer. Further, since the ion generator is not used, the yield is not reduced by the foreign matter generated by the ion generator.

FIG. 4 shows a yield distribution when a semiconductor wafer is cleaned by a conventional method. The representation of the figure is the same as that of FIG. In the example shown in FIG. 4, the cleaning liquid is supplied to the center of the semiconductor wafer. Further, a static elimination device such as an ion generator is not used.

As apparent from FIG. 4, the yield of the four semiconductor chips at the center of the semiconductor wafer is 60 to 80%.
It is clear that the yield is lower than the yield according to the present embodiment shown in FIG. Although the yield at the outer peripheral portion of the semiconductor wafer is lower than that of the example shown in FIG. 3, this is an improvement in the semiconductor manufacturing apparatus such as the stepper used in FIG. This is because the used semiconductor manufacturing apparatus is used.

As described above, in this embodiment, when cleaning the semiconductor wafer, first, the cleaning liquid is supplied to the non-circuit portion on the outer peripheral side of the semiconductor wafer to discharge the charged electric charges. Since the semiconductor chip is cleaned by supplying a cleaning liquid to the circuit portion later, damage to the semiconductor chip due to discharge can be prevented, and the yield can be improved.

Further, since an ion generator or the like for removing the charged electric charge is not used, the yield can be improved without being affected by foreign substances generated from the ion generator.

[0044]

According to the present invention, it is possible to prevent damage due to heat generated by the discharge of static electricity charged on a semiconductor wafer and to improve the yield.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a semiconductor cleaning apparatus according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a rotation operation of a nozzle used in the semiconductor cleaning device according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram of a yield distribution when a semiconductor wafer is cleaned using a semiconductor cleaning method according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a yield distribution when a semiconductor wafer is cleaned using a conventional semiconductor cleaning method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Non-conductive adsorption table 12 ... Shaft 14, 24, 44 ... Motor 16 ... Electromagnetic valve 18, 28 ... Pump 20 ... Nozzle 22 ... Arm 26 ... Electromagnetic valve 30 ... Cleaning liquid tank 32 ... Cleaning liquid 40 ... Splash guard 42 ... Linear Rail 46 ... Waste liquid cup 50 ... Control device 60,62,64 ... Driver circuit 70,72 ... Power supply 100 ... Semiconductor wafer P ... Pipe

 ──────────────────────────────────────────────────の Continuing on the front page (72) Koji Matsuyama, Inventor 832 Nagakubo, Horiguchi, Hitachinaka-shi, Ibaraki 2 Within Hitachi Measurement Engineering Co., Ltd. (72) Kazuhide Fukaya 882-Chair, Ichimo, Hitachinaka-shi, Ibaraki Hitachi, Ltd. (72) Inventor Toshiyuki Kono 832 Nagakubo, Horiguchi, Hitachinaka-shi, Ibaraki Prefecture 2 Within Hitachi Measurement Engineering Co., Ltd. (72) Inventor Tatsuya Inada 882 Ma, Hitachinaka-shi, Ibaraki Hitachi, Ltd. Within the business division

Claims (2)

[Claims] 1. A semiconductor cleaning apparatus comprising: a support for supporting a substrate on which a semiconductor integrated circuit portion is formed; and a cleaning liquid supply for supplying a cleaning liquid onto the substrate supported by the support. Supplying the cleaning liquid to the non-circuit portion where the semiconductor integrated circuit portion is not formed on the substrate supported by the support means, and then supplying the cleaning liquid to the semiconductor integrated circuit portion. Cleaning equipment. 2. A semiconductor cleaning method for cleaning a substrate by supplying a cleaning liquid onto a substrate supported by a supporting means, wherein the semiconductor integrated circuit portion on the substrate supported by the supporting means is not formed. A method of cleaning a semiconductor, comprising supplying the cleaning liquid to the non-circuit portion and then supplying the cleaning liquid to the semiconductor integrated circuit portion.