JP2023064905A - Regeneration system and regeneration method for pump filter for spin etching device - Google Patents

Abstract

To provide a regeneration system and a regeneration method for a pump filter for a spin-etching device which prevent clogging of the pump filter even when spin-etching a wafer consisting of a laminated body in which a support plate is attached to an ultra-thin wafer with an adhesive by the spin-etching device.SOLUTION: A regeneration system for a pump filter for a spin-etching device includes: an etchant circulation tank; an etchant supply line; an etchant recovery line; an etchant circulation line for forwardly flowing the etchant to the etchant circulation tank and a foreign matter discharge line for discharging foreign matter in the etchant; a pump filter; and a pressure mechanism for applying pressure in a direction opposite to the forward flow of the etchant circulation line to a filter portion of the pump filter, wherein a foreign matter collected by the pump filter is sent to the foreign matter discharge line.SELECTED DRAWING: Figure 1

Description

The present invention provides a system for regenerating a pump filter of an etchant circulation type spin etching apparatus for spin etching a semiconductor wafer, particularly a semiconductor wafer that is a laminate in which a support plate is attached to an ultra-thin wafer with an adhesive, and Regarding the playback method.

2. Description of the Related Art Conventionally, in a semiconductor manufacturing process, an etching process (also called spin etching) is performed by dripping an etchant while rotating a semiconductor wafer such as silicon (hereinafter referred to as "wafer").

As a wafer surface treatment apparatus for performing such spin etching, the applicant has proposed a wafer surface treatment apparatus with a waste liquid recovery mechanism that can recover the etchant used in spin etching, and has been well received (Patent document 1).

Since the used etchant can be recovered by using such a wafer surface treatment apparatus with a waste liquid recovery mechanism, the etchant used for etching can be recovered, filtered, and circulated by a pump to reuse the etchant. Conventionally, an etchant circulation type spin etching apparatus using a wafer surface treatment apparatus with a waste liquid recovery mechanism has been used. An etchant circulation type spin etching apparatus is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2002-100003. A pump protection filter (hereinafter referred to as "pump filter") for collecting foreign matter is used to protect the circulation pump of the etchant circulation type spin etching apparatus. An example of such a pump protection filter is disclosed in Patent Document 3 and the like.

On the other hand, the thickness of wafers, which are semiconductor substrates, is getting thinner and thinner, and wafers with a thickness of 100 μm or less, for example, with a thickness of about 60 μm, or ultra-thin wafers with even thinner thicknesses have come to be used. ing.

In the case of such an ultra-thin wafer, if it is only a wafer of silicon or the like, the wafer of the semiconductor substrate is likely to break due to the warp or distortion of the wafer, and cannot be handled. Therefore, before the wafer is subjected to processing such as mechanical polishing or chemical erosion, the wafer is subjected to the processing after the support plate is attached to the wafer with an adhesive.

A support glass made of glass is often used as the support plate, and an adhesive is often used as the affixing agent. As an example of a laminate in which such support glass is attached to a wafer, there is Patent Document 4, for example.

An example of such a laminate is shown in FIG. 2 of the present application. In FIG. 2, the laminate 100 has a structure in which a support glass 102 is adhered to a wafer W with an adhesive 104 .

However, in the above-described conventional etchant circulation type spin etching apparatus, when about 200 wafers are etched on a laminate in which a support plate is attached to ultra-thin wafers with an adhesive, the etchant circulation type Because the pump filter of the spin etching equipment was clogged with foreign matter, it was necessary to replace the pump filter every time it became clogged. Such a pump filter is relatively expensive, and it takes time to obtain it. Therefore, there is a problem that the etching process cannot be performed in the corresponding spin etching apparatus during that time.

When the inventors of the present application investigated the cause, as the number of ultra-thin wafers to be spin-etched increased, the amount of foreign matter adhering to the pump filter also increased. It was thought to be a foreign substance that occurred.

As a result of further investigation by the inventors of the present application, in the case of a laminated body in which the above-described support glass is attached to an ultrathin wafer, when an etching treatment is performed with a spin etching apparatus, the adhesive indicated by the dotted line in FIG. 2 is etched. The inventors have found that the cause of the problem is that the foreign matter is mixed in the etchant circulation path of the etchant circulation type spin etching apparatus described above.

JP 2001-267278 WO2006/103773 Special table 2002-523207 JP 2004-64040

The present invention has been made in view of the above-mentioned prior art. It is an object of the present invention to provide a system and method for regenerating a pump filter for a spin etching apparatus, which prevents clogging of the filter.

In order to solve the above-described problems, a pump filter regeneration system for a spin etching apparatus of the present invention is a pump filter regeneration system for an etchant circulation type spin etching apparatus for spin-etching a wafer, in which an etchant is stored. an etchant supply line for supplying the etchant from the etchant circulation tank to the upper surface of the wafer mounted on the etchant circulation type spin etching apparatus; an etchant recovery line for recovering the supplied etchant; an etchant circulation line for forwardly flowing the etchant to the etchant circulation tank and the etchant, which are switchably connected to the etchant recovery line; a foreign matter discharge line for discharging foreign matter in the etchant circulation line; a pump filter provided for collecting foreign matter in the etchant flowing in the forward direction in the etchant circulation line; A pump filter for a spin etching apparatus, comprising: a pressure mechanism that applies pressure in a direction opposite to a forward flow in a liquid circulation line, so that foreign matter collected by the pump filter is sent to a foreign matter discharge line. is a playback system.

The etchant circulation type spin etching apparatus includes a wafer rotation holding device for rotating and holding the wafer to be etched, and an etchant recovery mechanism provided around the wafer rotation holding device, wherein the etchant recovery mechanism and the An etchant recovery line is preferably connected so that the etchant supplied to the upper surface of the wafer flows to the etchant recovery line via the etchant recovery mechanism.

Preferably, the pressure is water and/or air pressure.

It is preferable that the wafer comprises a laminate to which a support plate is attached with an adhesive.

In the method for regenerating a pump filter for a spin etching apparatus of the present invention, the regeneration system for a pump filter for a spin etching apparatus is used to insert a filter portion of the pump filter of the etching liquid circulation line in the forward direction of the etching liquid circulation line. This is a method for regenerating a pump filter for a spin etching apparatus, wherein a pressure is applied in a direction opposite to the flow so that foreign matter collected in the pump filter is sent to a foreign matter discharge line.

Preferably, the pressure is water and/or air pressure.

The etchant circulation type spin etching apparatus of the present invention is an etchant circulation type spin etching apparatus for spin-etching a wafer, in which the regeneration system for the spin etching apparatus pump filter is incorporated.

It is preferable that the etchant circulation type spin etching apparatus includes a wafer rotation holding device that rotates and holds a wafer to be etched, and an etchant recovery mechanism provided around the wafer rotation holding device.

The wafer is preferably a laminate in which a support plate is attached to an ultrathin wafer with an adhesive.

The spin etching method of the present invention is a spin etching method in which a wafer is subjected to spin etching using the etchant circulation type spin etching apparatus.

The wafer is preferably a laminate in which a support plate is attached to an ultrathin wafer with an adhesive.

A wafer manufacturing method of the present invention is a wafer manufacturing method including an etching step by the spin etching method.

According to the present invention, clogging of the pump filter is prevented even when spin-etching a wafer composed of a laminated body in which a support plate is attached to an ultra-thin wafer with an adhesive using a spin-etching device. , it is possible to provide a regenerating system and regenerating method for a pump filter for a spin etching apparatus.

Further, according to the present invention, even when spin-etching a wafer composed of a laminated body in which a support plate is attached to an ultra-thin wafer with an adhesive, the pump filter is prevented from clogging. It is possible to provide an etchant circulation type spin etching apparatus, a spin etching method, and a wafer manufacturing method, all of which have a remarkable effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing one embodiment of a regeneration system for a pump filter for a spin etching apparatus according to the present invention; 1 is a schematic cross-sectional view showing one embodiment of a laminate in which a support plate is attached to an ultra-thin wafer with an adhesive; FIG. It is a photograph of the state where the adhesive in the dotted line part of FIG. be. 4 is a flow chart showing one embodiment of the operation of the pump filter regeneration system for a spin etching apparatus of the present invention. 4 is a timing chart showing the timing of a regeneration operation for regenerating a pump filter;

Embodiments of the present invention will be described below, but these embodiments are shown by way of example, and it goes without saying that various modifications are possible without departing from the technical idea of the present invention. In the drawings, the same members are denoted by the same reference numerals.

In FIG. 1, reference numeral 10 denotes an embodiment of a pump filter regeneration system for a spin etching apparatus according to the present invention.

A spin etching apparatus pump filter regeneration system 10 is a pump filter regeneration system for an etchant circulation type spin etching apparatus 12 for spin etching a wafer.

A pump filter regeneration system 10 for a spin etching apparatus includes an etchant circulation tank 14 in which an etchant 11 is stored, and an etchant circulation tank 14 on the upper surface of the wafer mounted on the etchant circulation type spin etching apparatus 12. It includes an etchant supply line 16 for supplying the etchant 11 from 14 and an etchant recovery line 18 for recovering the etchant 11 supplied to the upper surface of the wafer. In addition, in this specification, a line means piping.

Further, the spin etching apparatus pump filter regeneration system 10 includes an etchant circulation line 20 that is switchably connected to the etchant recovery line 18 and flows the etchant 11 forward to the etchant circulation tank 14. and a foreign matter discharge line 22 for discharging foreign matter in the etchant, a pump filter 24 provided for collecting foreign matter in the etchant flowing forward in the etchant circulation line 20, and the pump filter. 24 includes a pressure mechanism 26 that applies pressure in a direction opposite to the forward flow of the etchant circulation line 20. It is a pump filter regeneration system for a spin etcher, which is sent to

In the example of FIG. 1, the etchant recovery line 18 is provided with a three-way valve 28, and the etchant circulation line allows the etchant 11 to flow forward to the etchant circulation tank 14 by means of the three-way valve 28. 20 and a foreign matter discharge line 22 for discharging foreign matter in the etching liquid can be switched between the flow of the etching liquid.

The forward direction to the etchant circulation tank 14 refers to the direction of arrow A1, which is the opening direction of the three-way valve 28 in FIG. 1, and is the recovery direction to the etchant circulation tank 14 (FIG. 5). The direction opposite to the forward flow of the etchant circulation line 20 refers to the direction of arrow A2, which is the direction in which the three-way valve 28 is opened in FIG. 1, and is the foreign matter discharge direction (FIG. 5).

Foreign matter discharged through the foreign matter discharge line 22 is collected in a foreign matter collection box 32 having a foreign matter collection filter 30, and waste liquid is discharged.

The etchant circulation type spin etching apparatus 12 includes a wafer rotation holding device 34 for rotating and holding the wafer to be etched, and an etchant recovery mechanism 36 provided around the wafer rotation holding device 34 . In the illustrated example, the etchant recovery mechanism 36 is provided with a plurality of recovery cups that move up and down. Reference numeral 38 denotes a rotary shaft for rotating the rotary table of the wafer rotary holder 34 .

The etchant recovery mechanism 36 is connected to the etchant recovery line 18 so that the etchant 11 supplied to the upper surface of the wafer flows through the etchant recovery mechanism 36 to the etchant recovery line 18 . is configured to Reference numeral 37 is an etchant recovery cup, and reference numeral 39 is a rinse liquid recovery cup. These recovery cups of the etchant recovery mechanism 36 are moved up and down according to the chemical liquid to be recovered. When etching the wafer, the etchant recovery cup 37 is raised and the etchant 11 is recovered in the etchant recovery cup 37 . On the other hand, when rinsing the wafer, the rinse liquid recovery cup 39 is raised and the rinse liquid is recovered in the rinse liquid recovery cup 39 . Even if the liquid recovered by the etchant recovery mechanism 36 is a rinse liquid, there is a possibility that foreign matter may come out. and the waste liquid is drained.

As the etchant circulation type spin etching apparatus 12 including the wafer rotation holding device 34 and the etchant recovery mechanism 36, for example, the spin processing apparatus described in Patent Document 2 can be applied.

As the pump filter 24, a pump protection filter for a known wafer wet processing apparatus can be applied.

A pressure supply line 42 is provided downstream of the pump filter 24 of the etchant circulation line 20 and close to the pump filter 24 , and the pressure supply line extends in the forward direction of the etchant circulation line 20 . A pressure mechanism 26 is connected to apply pressure in a direction opposite to the flow of the gas. As the pressure mechanism 26, in the illustrated example, a water valve 44 for supplying pressure by water flow by supplying pure water, and an air valve 46 for supplying pressure by air flow by supplying air. and consists of

A drain line 48 is connected to the etchant circulation line 20 and is opened and closed by a drain valve 50 to drain the waste liquid.

A circulation pump 54 is connected to the tip of the circulation tank side valve 52 of the etchant circulation line 20 , and the recovered etchant 11 is sent to the etchant circulation tank 14 .

Reference numeral 56 denotes an etchant supply bottle for storing the etchant 11, which is connected to the etchant circulation tank 14 via a supply line 58 through a valve 60, and is replenished when the etchant 11 in the etchant circulation tank 14 decreases. act to The etchant supply bottle 56 functions as another etchant circulation tank. The etchant circulation tank 14 is provided with the etchant supply line 16 , and the etchant 11 is supplied to the etchant circulation type spin etching device 12 by opening and closing the valves 62 and 64 .

The etchant circulation tank 14 is also provided with a lower supply line 66 from which flow joins the etchant supply bottle 56 via a valve 65 and via a supply pump filter 68 and pump 70 to the etchant. An etchant can be supplied to the liquid supply line 16 .

A tank circulation line 72 is provided in the etchant circulation tank 14 , and the etchant is appropriately heated via a circulation pump filter 74 , a pump 76 and a temperature control device 78 . Reference numeral 80 is a thermometer.

Further, in FIG. 1, the etchant circulation type spin etching device 12 and the lines in which the etchant circulates around it are surrounded by dotted lines. is a chamber 82 containing Four such chambers 82 are provided. In FIG. 1, reference numeral 84 denotes a foreign matter discharge line for another chamber, and reference numeral 86 denotes a rinse liquid discharge line for another chamber.

Then, the pump filter regeneration system 10 for spin etching apparatus spin-etches a wafer composed of a laminate 100 in which a support glass 102 is attached to an ultra-thin wafer W with an adhesive 104, as shown in FIG. suitable for

FIG. 3 shows a photograph of a state in which the adhesive in the portion indicated by the dotted line in FIG. 2 is peeled off by etching and becomes a foreign matter.

3(a) and 3(b), reference numeral 88 denotes a filter portion of the pump filter 24, and reference numeral 90 denotes foreign matter. FIG. 3(b) is an enlarged view of FIG. 3(a). Conventionally, when about 200 wafers composed of the laminated body 100 including the ultra-thin wafers W shown in FIG. Since it was contained, the pump filter 24 had become clogged. The foreign bodies were approximately 150-300 μm wide and 1-100 mm long, and varied in size.

In the spin etching apparatus pump filter regeneration system 10 of the present invention, pressure is periodically applied to the filter portion of the pump filter 24 by the pressure mechanism 26 in the direction opposite to the forward flow of the etchant circulation line 20. Since it can be applied, the pump filter 24 is regenerated and clogging of the pump filter 24 does not occur. Conventionally, there was no other way but to discard the once clogged pump filter 24, but by reusing it, the life of the pump filter 24 itself can be extended until it breaks.

The etchant circulation type spin etching apparatus of the present invention is an etchant circulation type spin etching apparatus for spin-etching a wafer, in which the spin etching apparatus pump filter regeneration system 10 is incorporated.

In the spin etching method of the present invention, a wafer is spin-etched using an etchant circulation type spin-etching device in which the pump filter regeneration system 10 for a spin-etching device is incorporated.

Further, a wafer manufacturing method including an etching step by the spin etching method of the present invention is the wafer manufacturing method of the present invention.

Next, the operation timing of the spin etching apparatus pump filter regeneration method by the spin etching apparatus pump filter regeneration system 10 will be described with reference to FIGS. 4 and 5. FIG.

FIG. 4 is a flow chart showing one embodiment of the operation of the pump filter regeneration system for a spin etching apparatus of the present invention, and FIG. 5 is a timing chart showing the timing of the regeneration operation for regenerating the pump filter.

In the regenerating operation of the pump filter 24 for collecting foreign matter from the pump filter 24, first, as shown in step 100 in FIG. The respective valves of valve 46 and water valve 44 are closed.

If the pump filter 24 is completely clogged with foreign matter and then the regeneration operation (foreign matter recovery operation) is performed, the foreign matter is accumulated and pressed. It is preferable to determine the number of sheets for which the reproduction operation is to be performed in advance, such as every time, and to perform the reproduction operation regularly. In step 102, when the preset number of sheets has been reached, the process proceeds to step 104 to start the reproduction operation. The regeneration operation (foreign matter recovery operation) is set for about 45 seconds as shown in FIG.

In step 106 of FIG. 4 and FIG. 5, the etchant recovery line 18 is switched by the three-way valve 28 to switch from the arrow A1 side, which is the recovery side to the etchant circulation tank 14, to the A2 side, which is the foreign matter discharge side. The circulation tank side valve 52 is closed.

In step 108 of FIG. 4 and FIG. 5, as a regeneration operation with pure water, the water valve 44 is opened and the pure water flow in the opposite direction to the forward flow of the etching solution circulation line 20 is applied to the pump filter for 5 seconds. Apply to the filter part of 24.

Next, in step 110 of FIG. 4 and FIG. 5, the water valve 44 is closed and the air valve 46 is opened as a shock wave operation by air, so that the etchant circulation line 20 flows in the opposite direction to the forward direction. The filter portion of the pump filter 24 is hit with a large amount of air.

Furthermore, in step 112 of FIG. 4 and FIG. 5, as a regeneration operation with pure water, the air valve 46 is closed and the water valve 44 is opened to reverse the forward flow of the etchant circulation line 20. A stream of pure water is applied to the filter portion of the pump filter 24 for 5 seconds.

4 and 5, the water valve 44 is closed and the air valve 46 is opened as a shock wave operation by air, so that the forward flow of the etchant circulation line 20 is reversed. Air is applied to the filter portion of the pump filter 24 for 3 seconds.

After that, in step 116 of FIG. 4 and FIG. 5, the air valve 46 is opened for 10 seconds as recovery side water draining operation by air.

Then, in step 118 of FIG. 4 and FIG. 5, the drain valve 50 is opened for 10 seconds, and the air valve 46 is operated in the order of closing, opening, and closing, as an operation of draining water on the drain side with air.

In this way, the reproduction operation is completed by returning to the initial state of step 120 in FIG.

The system and method for regenerating a pump filter for a spin etching apparatus according to the present invention have the following advantages.

Conventionally, about 200 wafers, which consist of a laminated structure in which a support plate is attached to an ultra-thin wafer with an adhesive agent, are etched, and the pump filter through which the recovered etching solution circulates becomes clogged with foreign matter, requiring replacement. However, since it can be recycled, it can be used by extending the life of the pump filter itself until it breaks. This dramatically reduces the frequency of pump filter replacement.

By using pure water for foreign matter recovery, it is possible to reduce the cost of the mesh of the foreign matter recovery box 32 (the foreign matter recovery filter 30).

In addition, by concentrating foreign matter that causes clogging of the pump filters in the four chambers in one foreign matter recovery box 32, maintenance is facilitated. Conventionally, there were 4 pump filters under each chamber (4), so there were 4 maintenance points. There was a risk of chemical injury in replacing the In the present invention, since pure water or the like is used to collect the foreign matter, the atmosphere of the chemical solution can be reduced. This improved worker safety.

In the present invention, pump filters can be regenerated and used, so the number of pump filters in stock can be reduced. This saved costs.

for example,
Processing time: etching (60 sec) + rinse (60 sec) + dry (60 sec) + wafer exchange (20 sec),
However, since the foreign matter recovery operation (regeneration operation) takes 45 seconds, the foreign matter recovery operation can be performed while the drying process is being performed. Therefore, there is an advantage that the cycle time is not affected and the operating rate is not lowered.

There is no need to replace the pump filter during normal operation, eliminating the risk of stopping the spin etching equipment. In addition, we were able to suppress contamination when switching between the chemical solution and pure water by using a compact piping system for draining water.

It was possible to remove the foreign matter entangled in the pump filter by using shock waves with pure water and air. In addition, it is preferable to use a three-way valve, a ball valve type in which the pipe diameter and orifice do not change, since it is possible to reduce the catching of foreign matter.

10: Pump filter regeneration system for spin etching device, 11: Etching liquid, 12: Etching liquid circulation type spin etching device, 14: Etching liquid circulation tank, 16: Etching liquid supply line, 18: Etching liquid recovery line, 20: Etching solution circulation line, 22, 84: foreign matter discharge line, 24: pump filter, 26: pressure mechanism, 28: three-way valve, 30: foreign matter recovery filter, 32: foreign matter recovery box, 34: wafer rotation holding device, 36: etching liquid recovery mechanism, 37: etchant recovery cup, 38: rotating shaft, 39: rinse liquid recovery cup, 40, 86: rinse liquid drain line, 42: pressure supply line, 44: water valve, 46: air valve, 48: drainage line, 50: drainage valve, 52: circulation tank side valve, 54: circulation pump, 56: etchant supply bottle, 58: supply line, 60, 62, 64, 65: valves, 66: lower supply line, 68: supply pump filter, 70, 76: pump, 72: tank circulation line, 74: circulation pump filter, 78: temperature control device, 80: thermometer, 82: chamber, 88: filter part, 90: foreign matter, 100: laminate, 102: support glass, 104: adhesive, W: wafer.

Claims (12)

A regeneration system for a pump protection filter of an etchant circulation type spin etching device for spin etching a wafer,
an etchant circulation tank in which the etchant is stored;
an etchant supply line for supplying the etchant from the etchant circulation tank to the upper surface of the wafer mounted on the etchant circulation type spin etching apparatus;
an etchant recovery line for recovering the etchant supplied to the upper surface of the wafer;
an etchant circulation line that forwardly flows the etchant to the etchant circulation tank and a foreign matter discharge line that discharges foreign matter in the etchant, which are switchably connected to the etchant recovery line;
a pump filter provided to collect foreign matter in the etchant flowing in the forward direction in the etchant circulation line;
a pressure mechanism that applies pressure in a direction opposite to the forward flow of the etchant circulation line to the filter portion of the pump filter;
including
A system for regenerating a pump filter for a spin etching apparatus, wherein foreign matter collected in the pump filter is sent to a foreign matter discharge line. The etchant circulation type spin etching device,
a wafer rotation holding device for rotating and holding the wafer to be etched; and an etchant recovery mechanism provided around the wafer rotation holding device,
The etchant recovery mechanism and the etchant recovery line are connected to each other, and the etchant supplied to the upper surface of the wafer flows through the etchant recovery mechanism to the etchant recovery line. Item 2. A system for regenerating a pump filter for a spin etching apparatus according to Item 1. 3. The system for regenerating a pump filter for a spin etching apparatus according to claim 1, wherein said pressure is pressure by water flow and/or air. 4. The system for regenerating a pump filter for a spin etching apparatus according to claim 1, wherein said wafer is a laminate in which a support plate is attached to an ultra-thin wafer with an adhesive. Using the pump filter regeneration system for a spin etching apparatus according to any one of claims 1 to 4, a filter portion of the pump filter of the etchant circulation line is provided with a flow opposite to the forward flow of the etchant circulation line. A method for regenerating a pump filter for a spin etching apparatus, wherein foreign matter collected in the pump filter is sent to a foreign matter recovery line by applying a directional pressure. 6. The method for regenerating a pump filter for a spin etching apparatus according to claim 5, wherein said pressure is pressure by water flow and/or air. An etchant circulation type spin etching apparatus for spin etching a wafer, comprising the pump filter regeneration system for a spin etching apparatus according to any one of claims 1 to 4. The etchant circulation type spin etching device,
8. The etchant circulation type spin etching apparatus according to claim 7, further comprising a wafer rotation holding device for rotating and holding a wafer to be etched, and an etchant recovery mechanism provided around said wafer rotation holding device. 9. The etchant circulation type spin etching apparatus according to claim 7, wherein said wafer is a laminate in which a support plate is attached to an ultra-thin wafer with an adhesive. A spin etching method, comprising performing spin etching on a wafer using the etchant circulation type spin etching apparatus according to any one of claims 7 to 9. 11. The spin etching method according to claim 10, wherein said wafer is a laminate in which a support plate is attached to an ultra-thin wafer with an adhesive. A method for manufacturing a wafer, comprising an etching step by the spin etching method according to claim 10 or 11.

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