JPH11307502A - Apparatus for single-wafer processing type spin cleaning and drying of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for single-wafer processing type spin cleaning and drying of semiconductor wafers, capable of always blowing clean cleaning liq. without contamination and inert gas on the wafer lower face by eliminating the need for a rotary joint to avoid producing particles due to the friction of movable parts. SOLUTION: A rotary shaft 2 located at the bottom face center of a turn table 1 is fixed directly vertically down, a hollow nozzle shaft 5 inserted in the shaft 2 below which a closed feed tank 7 has a feed hole 8 of a cleaning liquid 15 and a feed hole 9 of a compressed inert gas 16 at adequate positions, and also has a discharge port 10 for cleaning lig. at the bottom, the top end of the nozzle shaft 5 inserted in the rotary shaft 2 points the lower face of a wafer W from the center of the turn table 1 via a spray nozzle 6 and the lower end of the nozzle shaft 5 extends into the feed tank 7 to be opened near the tank bottom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-wafer spin cleaning / drying apparatus for a semiconductor wafer, and more particularly to a single-wafer spin cleaning / drying apparatus for a semiconductor wafer capable of cleaning and drying a lower surface of a wafer cleanly and effectively. It relates to a drying device.

[0002]

2. Description of the Related Art FIG. 3 shows a first example of a conventional single-wafer spin cleaning / drying apparatus for semiconductor wafers. In the figure, 3
Reference numeral 1 denotes a spin tank, and a rotary table 32 for mounting and rotating a semiconductor wafer (hereinafter, abbreviated as “wafer”) W in the spin tank 31 is arranged. At the center of the lower surface of the rotary table 32, a hollow rotary shaft 33 driven to rotate by a motor (not shown) or the like is fixedly provided.

The rotary shaft 33 extends downward through the spin tank 31, and a rotary joint 34 for supplying a negative pressure for vacuum suction of the wafer W is attached to a lower end thereof. Further, the rotary table 32
A cleaning nozzle 35 for spraying a cleaning liquid (for example, pure water) toward the lower surface of the wafer W is disposed at an appropriate position on the lower surface side of the wafer W, and an inert compressed gas for drying toward the lower surface of the wafer W. A drying nozzle 36 for spraying (for example, N ₂ gas) is disposed. Although a cleaning nozzle and a drying nozzle for cleaning / drying the upper surface of the wafer W are arranged on the upper surface side of the wafer W, the cleaning / drying mechanism on the upper surface side is not shown.

In the conventional apparatus having the above structure, the lower surface of the wafer W is cleaned and dried as follows. That is, first, a negative pressure is applied to the lower surface of the wafer W through the hollow portions of the rotary joint 34 and the rotating shaft 33 to fix the wafer W on the rotary table 32 by vacuum suction. Next, the rotating shaft 33 is rotated by a motor (not shown) or the like, and the cleaning liquid is sprayed from the cleaning nozzle 35 toward the lower surface of the wafer W while rotating the rotary table 32 at a predetermined speed, thereby cleaning the lower surface of the wafer. After the cleaning is completed, the wafer W is
An inert gas was blown toward the lower surface of the wafer to dry the lower surface of the wafer.

FIG. 4 shows a second example of a conventional single-wafer spin cleaning / drying apparatus for semiconductor wafers. This second conventional apparatus fixes a wafer W on a rotary table 32 by a mechanical chuck 37, and provides a cleaning nozzle 35 (or a drying nozzle) provided on the rotary table 32 through a hollow portion of a rotary joint 34 and a rotary shaft 33. 36), a cleaning liquid (or an inert pressurized gas) is sprayed from the drying nozzle 3 provided at an appropriate position on the lower surface side of the rotary table 32.
6 (or the cleaning nozzle 35) blows an inert compressed gas (or a cleaning liquid).

[0006]

As described above, in the single-wafer spin cleaning / drying apparatus for semiconductor wafers, a negative pressure or cleaning liquid is passed through a hollow rotary shaft 33 to clean and dry the lower surface of the wafer. Alternatively, an inert compressed gas is supplied, and the negative pressure, the cleaning liquid or the inert compressed gas is supplied to the lower portion of the rotating shaft 32.
It was necessary to attach a rotary joint 34 for feeding to the hollow portion 2.

As shown, a rotary joint 34 is attached to a rotating shaft 33 and rotates at a high speed integrally with the rotating shaft 33. A rotary seal 34b is attached to the rotor 34a.
Stator (stator) 34c connected via the
It is composed of For this reason, a large frictional force is always applied to the rotating seal portion 34b, which connects the high-speed rotating rotor 34a and the stationary stator 34b, and the rotating seal portion 34b is rubbed. There is a possibility that the wafer W may enter the shaft 33 and contaminate the wafer W. In addition, conventional single wafer spin cleaning
In the drying apparatus, since the washing nozzle 35 and the drying nozzle 36 are provided in the spin bath 31, the air flow in the chamber is disturbed, and particles are likely to be increased.

[0008] The present invention has been made to solve the above problems, and eliminates the need for a rotary joint.
Single-wafer spin cleaning of semiconductor wafers, which eliminates the generation of particles due to friction of moving parts and can always spray a clean cleaning solution and inert gas without contamination on the lower surface of the wafer.
It is an object to provide a drying device.

[0009]

In order to achieve the above-mentioned object, a single wafer spin cleaning / drying apparatus for a semiconductor wafer according to the present invention is provided. In a single wafer spin cleaning / drying apparatus for cleaning and drying the lower surface of a wafer by sequentially spraying a cleaning liquid and an inert compressed gas on the lower surface, the rotary table is located at the center of the lower surface of the rotary table, A rotary shaft having a hollow nozzle shaft inserted therethrough is fixed vertically downward, and a cleaning liquid supply port and an inert compressed gas supply port are provided at appropriate positions below the rotary shaft, and a lower bottom portion is provided. A closed supply tank provided with a cleaning liquid discharge port, and the upper end of a nozzle shaft inserted through the rotary shaft is provided with a rotary nozzle through an injection nozzle. Together to face toward the wafer lower surface from the center of Le, the lower end of the nozzle shaft is obtained by opening the extending therefrom to the tank under the bottom near to the supply tank.

[0010] The nozzle shaft may be omitted, and the rotary shaft may also serve as a nozzle shaft.

[0011]

When a predetermined amount of the cleaning liquid is supplied from the cleaning liquid supply port into the supply tank and then an inert compressed gas (for example, N ₂ gas) having a predetermined pressure is supplied from the inert gas supply port into the supply tank, The cleaning liquid in the supply tank is sent from the lower end opening of the nozzle shaft to the upper end of the shaft through the hollow part by the gas pressure of the inert compressed gas, and is jetted from the upper jet nozzle toward the lower surface of the wafer. Then, the cleaning liquid attached to the lower surface of the wafer is washed away at a high speed in the outer peripheral direction along the lower surface of the wafer by the centrifugal force caused by the high-speed rotation of the rotary table, and cleanly cleans the lower surface of the wafer.

After cleaning the lower surface of the wafer, the cleaning liquid outlet is opened to discharge the cleaning liquid remaining in the supply tank to the outside of the tank, and then the inert compressed gas is supplied into the supply tank.
The inert compressed gas is sent from the lower end opening of the nozzle shaft to the upper end of the shaft through the hollow portion, is jetted from the upper jet nozzle toward the lower surface of the wafer, and dries the lower surface of the wafer rotating at high speed.

As described above, in the case of the present invention, a rotary joint is not required, particles are not generated due to friction of a movable portion, and a clean cleaning solution and an inert gas free from contamination can always be sprayed on the lower surface of the wafer.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a single wafer type spin cleaning / drying apparatus for a semiconductor wafer according to the present invention. The spin tank surrounding the rotary table and the upper-side cleaning / drying mechanism for cleaning / drying the upper surface of the wafer are not shown.

In FIG. 1, reference numeral 1 denotes a rotary table on which a wafer W is placed and rotated.
A rotary shaft 2 is fixedly mounted at the center of the lower surface of the pulley. The pulley 3 is rotatably driven by a motor or the like (not shown) so that the pulley 3 can be guided and rotated by a guide mechanism 4.

A hollow nozzle shaft 5 is integrally inserted into the rotary shaft 2. The upper end of the nozzle shaft 5 is connected to the rotary table 2 via the injection nozzle 6.
And the lower end is extended downward, enters the supply tank 7 connected and fixed to the lower part of the guide mechanism 4, and is opened near the lower bottom thereof. .

The supply tank 7 supplies a cleaning liquid (eg, pure water) and an inert compressed gas (eg, N 2) to the nozzle shaft 5.
₂ ) a cleaning liquid supply port 8 for supplying a cleaning liquid to the left and right side walls.
An inert gas supply port 9 for supplying an inert compressed gas is provided, and a cleaning liquid discharge port 10 is provided at the bottom of the tank. As will be apparent from the operation description to be described later, at the time of cleaning, the cleaning liquid is supplied from the cleaning liquid supply port 8 to fill the tank, and at the time of drying, the inert compressed gas is supplied from the inert gas supply port 9. The tank is filled.

Although not shown, the guide mechanism 4 incorporates a sealing mechanism such as a magnetic seal, a mechanical seal, and a labyrinth. The supply tank 7 passes through a gap in the outer peripheral surface of the rotating shaft 2 that rotates at a high speed. It prevents the inert compressed gas inside from leaking to the outside. In addition, a seal member 11 for preventing leakage of inert gas is interposed at the boundary between the guide mechanism 4 and the supply tank 7 as necessary, so that further sealing is achieved.

The cleaning liquid supply port 8, the inert gas supply port 9, and the cleaning liquid discharge port 10 of the supply tank 7 are connected to valves (not shown) through a cleaning liquid supply pump, an inert gas supply pump, Connected to pump.

The operation of cleaning and drying the lower surface of the wafer of the apparatus of the present invention having the above-described configuration will be described with reference to the operation explanatory diagram of FIG. (1) Processing of Supplying Cleaning Liquid to Supply Tank (FIG. 2A) The wafer W to be cleaned and dried is supplied to the rotary table 1 by a known chucking mechanism (not shown) provided on the outer peripheral edge of the rotary table 1. It is placed and fixed on the table with a slight gap from the table surface. Next, after closing the valve 15 of the cleaning liquid outlet 10 of the supply tank 7, the valve 12 is closed.
To open the cleaning liquid 1 into the supply tank 7 from the cleaning liquid supply port 8.
Send 5

When a certain amount of the cleaning liquid 15 flows into the supply tank 7, a flow rate sensor (not shown) detects this and closes the valve 12 to stop the supply of the cleaning liquid 15. Thus, the inside of the supply tank 7 is filled with a certain amount of the cleaning liquid 15 as shown in FIG. When the supply tank 7 is filled with a certain amount of the cleaning liquid 15, the pulley 3 is driven to rotate by a motor (not shown), and the rotary shaft 2, the nozzle shaft 5 and the rotary table 1 are rotated at a high speed at a predetermined speed.

(2) Cleaning of Wafer Lower Surface with Cleaning Solution (FIG. 2B) As described above, a certain amount of the cleaning solution 1 is supplied into the supply tank 7.
When the rotary table 1 is rotated at a high speed, the valve 13 of the inert gas supply port 9 is opened, and the inert compressed gas 16 having a predetermined pressure is sent from the inert gas supply port 9 into the supply tank 7. The pay starts.

When the inert pressurized gas is supplied, the cleaning liquid 15 stored in the supply tank 7 is moved from the lower end opening of the nozzle shaft 5 to the inside of the shaft hollow by the pressure as shown in FIG. And is ejected from the ejection nozzle 6 at the upper end of the shaft toward the lower surface of the wafer W rotating at a high speed. The cleaning liquid adhering to the lower surface of the wafer 1 is washed away along the lower surface of the wafer at a high speed by the centrifugal force caused by the high-speed rotation of the rotary table 1 to clean the lower surface of the wafer.

The lower end opening of the nozzle shaft 5 is
Since the rotary table 1 rotates at a high speed in synchronization with the high-speed rotation, a vortex is generated in the cleaning liquid 15 in the supply tank 7, which may cause the nozzle shaft 5 to suck up the cleaning liquid. For this purpose, the length of the nozzle shaft 5 and the supply amount of the cleaning liquid 15 may be set in advance in anticipation of the change in the liquid level.

(3) Draining treatment of cleaning liquid (FIG. 2C) When cleaning of the lower surface of the wafer W is completed, the cleaning liquid outlet 10
Is opened, and all the cleaning liquid 15 remaining in the supply tank 7 is drained from the cleaning liquid outlet 10 as shown in FIG.

(4) Drying Process Using Inert Compressed Gas (FIG. 2D) When all of the cleaning liquid 15 in the supply tank 7 is drained, the valve 14 is closed and the cleaning liquid outlet 10 is closed.
On the other hand, the inert compressed gas 16 is continuously supplied from the inert gas supply port 9. Therefore, the inert compressed gas fills the supply tank 7 and, as shown in FIG. 2 (D), passes through the lower end opening of the nozzle shaft 5, the inside of the hollow shaft, and the high-speed rotating wafer from the injection nozzle 6 at the upper end of the shaft. It is sprayed toward the lower surface of W to dry the lower surface of the wafer.

When the drying of the wafer 1 is completed, the rotary table 1 is stopped, and the wafer W is taken out of the illustrated apparatus and transported to the next processing step.

As described above, in the case of the present invention, the spray nozzle 6 for spraying the cleaning liquid and the inert compressed gas is provided at the rotation center position of the rotary table 1 as a dual-purpose nozzle. The cleaning liquid 15 and the inert compressed gas 16 are injected from the injection nozzle 6 to the lower surface of the wafer 1 through the hollow portion of the nozzle shaft 5.

Therefore, unlike the conventional apparatus, there is no need to install a washing nozzle or a drying nozzle below the rotary table in the spin tank, and the cleaning and drying nozzles installed in the spin tank are not required.
The drying mechanism can be simplified, and workability at the time of assembling the apparatus and performing maintenance can be improved. In addition, since a rotary joint is not required, particles are not generated from the movable portion of the rotary joint,
The reliability of the device can be improved and the product yield can be increased.

In the above embodiment, the separate nozzle shaft 5 is inserted into the rotary shaft 2. However, the nozzle shaft 5 may be eliminated and the rotary shaft 2 may also serve as the nozzle shaft 5. .

[0031]

As described above, when the single wafer type spin cleaning / drying apparatus for a semiconductor wafer according to the present invention is used,
A cleaning liquid and an inert compressed gas are fed into the hollow portion of the shaft from the lower end opening of the nozzle shaft, which is extended to near the lower bottom of the supply tank, and is blown from the injection nozzle at the upper end of the nozzle shaft toward the lower surface of the wafer. This eliminates the need for a rotary joint, eliminates the generation of particles due to friction of the movable portion, and allows a clean cleaning liquid and an inert gas free from contamination to be constantly sprayed onto the lower surface of the wafer. Further, since the cleaning liquid and the inert compressed gas are all jetted from the center position of the rotary table toward the lower surface of the wafer, the air flow in the chamber of the spin tank is not disturbed as in the related art. For this reason, the washing process and the drying process can be performed extremely finely, and the reliability of the apparatus can be remarkably improved.

When the rotary shaft also serves as a nozzle shaft, the structure of the apparatus can be further simplified.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of the present invention.

FIGS. 2A to 2D are explanatory diagrams of the operation of the apparatus of FIG. 1;

FIG. 3 is a schematic vertical sectional view showing a first example of a conventional single-wafer spin cleaning / drying apparatus for semiconductor wafers.

FIG. 4 is a schematic vertical sectional view showing a second example of a conventional single-wafer spin cleaning / drying apparatus for semiconductor wafers.

[Explanation of symbols]

 W Semiconductor wafer 1 Rotary table 2 Rotary shaft 3 Pulley 4 Guide mechanism 5 Nozzle shaft 6 Injection nozzle 7 Supply tank 8 Cleaning liquid supply port 9 Inert gas supply port 10 Cleaning liquid discharge port 11 Seal member 12 to 14 Valve 15 Cleaning liquid 16 Inactive squeezing gas

Claims (2)

[Claims] 1. A semiconductor wafer having a lower surface cleaned and dried by sequentially spraying a cleaning liquid and an inert compressed gas on the lower surface of the semiconductor wafer while rotating the semiconductor wafer on a rotary table at a high speed. In the leaf-type spin cleaning / drying apparatus, a rotary shaft, in which a hollow nozzle shaft is inserted, is fixed vertically downward at a center of the lower surface of the rotary table, and below the rotary shaft, A cleaning liquid supply port and an inert compressed gas supply port are provided at appropriate positions, and a closed-type supply tank having a cleaning liquid discharge port is provided at a lower bottom portion, and an upper end of a nozzle shaft inserted into the rotary shaft is provided. Is directed from the center position of the rotary table toward the lower surface of the wafer via the injection nozzle, and the lower end of the nozzle shaft is located inside the supply tank. In extending therefrom with single wafer spin cleaning and drying apparatus of a semiconductor wafer, characterized in that is opened in the vicinity of the tank under the bottom. 2. The single wafer spin cleaning / drying apparatus for semiconductor wafers according to claim 1, wherein said nozzle shaft is omitted, and said rotary shaft also serves as a nozzle shaft.