JPH104077A - Wafer cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically supplement a cleaning liq. for a cleaning tank and drain the dirty cleaning liq. at adequate timings. SOLUTION: The cleaner is composed of a cleaning unit 2' and controller 3 which is composed of a control circuit 31, MPU 32 and memory 33. Adequate timings obtained by test, etc., are previously set in the memory 33, a first and second valves 22 and 26 are opened by the control of the control circuit 31 at adequate timings to supplement reserved cleaning liq. Lq to a cleaning tank 23 and flow the dirty cleaning liq. Lq' into a buffer tank 27. A third valve 281 is opened according to a detection signal from a liq. level sensor 271 to drain the dirty liq. Lq' out by fixed amounts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a cleaning apparatus for cleaning a wafer, and more particularly to a cleaning apparatus for automatically discharging and replenishing a cleaning liquid.

[0002]

2. Description of the Related Art In the manufacture of semiconductor ICs, an IC pattern is formed on the surface of a silicon wafer by a multi-step process, and the wafer is cleaned by a cleaning device at each step of the process to remove dust and fine metal powder. Foreign matter has been removed. FIG. 2 shows a schematic configuration of a conventional wafer cleaning apparatus 2, in which a replenisher bath 21, a first valve 22, a cleaning bath 23,
Pump 24, filter 25, and the second valve 26 is constructed by connecting the pipe p _i as shown, the cleaning tank 22
Are provided on both sides thereof.

[0003] In the wafer 1 wash, satisfies the clean cleaning liquid L _Q to the cleaning tank 23, to which by immersing the plurality of wafers 1 are washed predetermined time. During this cleaning, since the foreign matter, such as dust attached to the wafer 1 are mixed liberated in the washing liquid L _Q, in cleaning and suction cleaning liquid L _Q from the bottom of the cleaning tank 23 by operating the pump 24, the foreign matter mixed thereto is removed by the filter 25, the cleaning liquid L _Q circulates the cleaning tank 23 through the liquid reservoir container 232. By this circulation, not only the removal of the foreign matter but also the cleaning is efficiently performed. However, the cleaning liquid L _Q
Some metals, such as aluminum, on which the pattern of the wafer 1 is formed dissolve, and the dissolved metals are filtered.
Since it is not 24 in removing, cleaning liquid L _Q is contaminated gradually,
The cleaning ability is reduced to become the contaminated cleaning liquid L _Q ′. Therefore,
The replenisher tank 21 advance satisfies always clean refilling cleaning liquid L _Q, when opening the first and second both valves 22 and 26 at the time required, contaminated cleaning liquid L _Q 'is to the outside through a liquid reservoir container 232 is discharged, the amount replenished cleaning liquid L _Q is replenished into the cleaning tank 23 through the liquid reservoir container 231, the cleaning bath 23 is maintained at a good cleaning capability.

[0004]

In the cleaning device 2, the first and second valves 22, 26 are opened and closed manually by an operator at all times. However, the degree of contamination of the cleaning liquid L _Q is different by the type and number of wafers the size of the cleaning liquid L _Q, since this cleaning time also changes Te facing, both in response to these variables valve 22, 24, 32
It is not always easy to release 6 at the right timing intervals. Therefore, it is preferable that an appropriate timing interval is checked in advance, and the valves 22 and 26 are automatically opened at this timing interval. This also gives
There is an advantage that the operator need not always wait. The present invention has been made in view of the above, first and the opening and closing of the second of the two valves 22 and 26 is automatically controlled, contamination cleaning liquid L _Q discharged replenishing the cleaning liquid L _Q supplemented with an accurate timing of the ' The task is to do it.

[0005]

SUMMARY OF THE INVENTION The present invention is a wafer cleaning apparatus which solves the above-mentioned problems, and comprises a cleaning section and a control section. The cleaning unit is connected to a replenisher tank filled with a clean replenishment cleaning liquid via a first valve that opens and closes the replenisher tank by an opening / closing mechanism, and is a cleaning liquid filled with a cleaning liquid for immersing and cleaning a wafer. A tank, a pump and a filter connected to a pipe between the bottom surface and the upper portion, for filtering foreign substances mixed in the cleaning liquid during wafer cleaning, and circulating the cleaning liquid to the cleaning tank, and an opening / closing mechanism for the upper part of the cleaning tank And a liquid level sensor for detecting the level of the contaminated cleaning liquid when a contaminated cleaning liquid in which metals are dissolved and contaminated during cleaning of the wafer flows in during the cleaning of the wafer. A third valve, which is opened and closed by an opening and closing mechanism for discharging, comprises a buffer tank connected to a pipe. The control unit controls the opening and closing mechanism of the first valve and the second valve at a predetermined timing interval, controls the opening and closing mechanism of the third valve based on the detection signal of the liquid level sensor, and controls the predetermined timing interval Is set in advance.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the above-described cleaning section, as in the prior art, a wafer is cleaned by immersing it in a cleaning liquid filled in a cleaning tank, and the cleaning liquid in the cleaning liquid is pumped by a pump onto the bottom of the cleaning tank (outer tank). The foreign matter mixed in is removed by the filter, returned to the lower portion of the washing tank (inner tank), and circulated in an overflowing manner. On the other hand, in the control unit,
At a predetermined timing interval preset in the memory,
The first and second valves are respectively opened by controlling the opening / closing mechanism, whereby the contaminated cleaning liquid in the cleaning tank flows into the buffer tank, and a replenishing cleaning liquid is supplied to the cleaning tank instead. Cleaning performance is maintained. on the other hand,
When the level of the contaminated cleaning liquid flowing into the buffer tank reaches a predetermined level, the liquid level is detected by a liquid level sensor, and this detection signal is input to the control unit, and the third valve is opened with the opening and closing mechanism controlled. A certain amount of the contaminated cleaning liquid in the buffer tank is discharged out of the apparatus.

[0007] In the above, the predetermined timing interval, the degree of contamination of the cleaning liquid L _Q due number size of the cleaning liquid type and the wafer, the cleaning time relationship to this, previously determined by tests like, which from both The exact timing interval for opening the valve is determined and set in memory. The reason why the buffer tank is provided is that the discharge amount of the contaminated cleaning liquid is quantified, and therefore the replenishment amount of the replenishment cleaning liquid is also quantified, which is convenient for controlling the cleanliness of the cleaning liquid in the cleaning tank.

[0008]

FIG. 1 shows an embodiment of a wafer cleaning apparatus 10 according to the present invention. The cleaning apparatus 10 includes a cleaning section 2 'and a control section 3. The cleaning unit 2 ′ is provided with an opening / closing mechanism for the first and second valves 22 and 26 in the conventional wafer cleaning apparatus 2 shown in FIG.
221,261 were respectively added, also the buffer tank 27 having a liquid level sensor 271 to the second valve 26 is added to connect the pipe p _i, constituted by a third valve 28 and a pipe connected to the bottom surface. The valve 28 also has an opening / closing mechanism 281. The control unit 3 includes a control circuit 31, an MPU 32, and a memory (MEM) 33, and is connected to each unit of the cleaning unit 2 'as illustrated. The memory 33 stores the cleaning liquid _{LQ according to} the type of the cleaning liquid LQ and the number of wafers 1 to be cleaned.
_The correlation between the degree of contamination of _Q and the cleaning time is examined by a previous test or a conventional experience, and an appropriate timing interval for opening both valves 22 and 26 is determined and set based on this.

[0009] In the cleaning portion 2 ', a plurality of wafers 1 which is immersed in the cleaning liquid L _Q of the cleaning tank 22, while being efficiently cleaned by the circulation of the cleaning liquid L _Q, mixed in the cleaning liquid L _Q during cleaning The removed foreign matter is removed by the filter 25 as in the conventional case. In the control unit 3, the memory 33
Is read out to the MPU 32 and passed to the control circuit 31, whereby an opening signal is given to the opening and closing mechanisms 221 and 261 of the first and second valves 22 and 26 at the proper timing intervals. Both valves 22, 26 are opened.
With these openings, the contaminated cleaning liquid L _Q ′ is discharged from the liquid reservoir 232.
There flows into the buffer tank 27, replenishment cleaning liquid L _Q is replenished to flow into the cleaning bath 23 from the replenishing tank 21. Buffer tank
When the level of the contaminated cleaning liquid L _Q ′ flowing into 27 reaches the level of the liquid level sensor 271, it outputs a detection signal and inputs it to the MPU 32, and the control circuit 31 gives an opening signal to the opening / closing mechanism 281 according to the instruction. Then, the third valve 28 is opened, and a certain amount of the contaminated cleaning liquid L _Q ′ is discharged out of the apparatus.

[0010]

As described above, in the wafer cleaning apparatus of the present invention, the control of opening and closing both the first and second valves is automated, so that the contaminated cleaning liquid in the cleaning tank flows into the buffer tank, and the replenishing tank. And replenishment of the replenishment washing solution,
The cleaning is performed at an appropriate timing interval determined by a previous test, so that the cleaning liquid in the cleaning tank is always maintained in a state of good cleaning ability, and the contaminated cleaning liquid flowing into the buffer tank is discharged to the outside by a fixed amount. It is convenient for controlling the cleanliness of the cleaning liquid in the cleaning tank, the cleaning liquid having good cleanliness is automatically maintained in the cleaning tank, and the operator does not need to always wait for the cleaning device. There are big things.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wafer cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional wafer cleaning apparatus.

[Explanation of symbols]

1 wafer 2 conventional wafer cleaning device 21 replenisher tank
22 ... first valve, 23 ... washing tank, 231,232 ... liquid storage container,
24: pump (P), 25: filter, 26: second valve,
2 ': Cleaning unit, 221, 261, 281: Opening / closing mechanism, 27: Buffer tank, 271: Liquid level sensor, 3: Control unit, 31: Control circuit, 32: MPU, 33: Memory (MEM), 10: Wafer cleaning of the present invention Equipment, L _Q … cleaning solution or replenishment cleaning solution, L _Q ′… contaminated cleaning solution, p _i … pipe.

Claims (1)

[Claims] The cleaning unit includes a cleaning unit and a control unit. The cleaning unit includes a replenishing solution tank filled with a clean replenishing cleaning solution, and a first valve that opens and closes the replenishing solution tank by an opening and closing mechanism. A cleaning tank filled with a cleaning liquid for cleaning the immersed wafer, connected to a pipe, and connected to a pipe between a bottom surface and an upper part of the cleaning tank to filter foreign substances mixed in the cleaning liquid during the cleaning of the wafer; Is connected to the upper part of the cleaning tank via a pump and a filter, and a second valve that is opened and closed by an opening / closing mechanism with respect to the upper part of the cleaning tank. A contaminated cleaning solution that flows in, a liquid level sensor for detecting the level of the contaminated cleaning solution, a buffer valve connected to a third valve on the bottom surface that is opened and closed by an opening / closing mechanism for discharge, and a control unit, , The opening and closing mechanism of the first valve and the second valve is controlled at a predetermined timing interval, the opening and closing mechanism of the third valve is controlled by a detection signal of the liquid level sensor, and the predetermined timing interval is set in advance. A wafer cleaning apparatus having a memory for setting.