Automatic silicon wafer dehydration device with IPA recycling function

Abstract

The utility model discloses an automatic silicon wafer dehydration device with an IPA recycling function, and belongs to the field of semiconductor manufacturing equipment. The device comprises a flower basket lifting basket device and a silicon wafer dewatering tank, the silicon wafer dewatering tank is divided into a first-stage dewatering tank and a second-stage dewatering tank which are communicated through a stepped overflow structure, and the overflow direction is from the first-stage dewatering tank to the second-stage dewatering tank; a liquid outlet in the bottom of the primary dehydration tank is connected into a distillation device for performing temperature-controlled distillation on the IPA waste liquid through a pipeline with a first one-way valve, a gas phase outlet of the distillation device is connected into an inlet of a drying cylinder through a pipeline with a second one-way valve, and an outlet of the drying cylinder is connected into an inlet of a condensing cylinder through a pipeline with a third one-way valve; and a liquid phase outlet of the condensing cylinder is connected into the collecting container through a pipeline with a fourth one-way valve. According to the invention, the dehydration effect can be ensured, the IPA dehydrating agent can be recycled as much as possible, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor manufacturing equipment, in particular to an automatic silicon wafer dehydration device with IPA recovery and recycling function. Background Art

[0002] Isopropyl alcohol (IPA, chemical formula C 3 H 8 O) is a colorless transparent liquid with an odor similar to a mixture of ethanol and acetone. It is an important chemical product and raw material, mainly used as a dehydrating agent and cleaning agent in the pharmaceutical, cosmetics, plastics, fragrances, coatings and electronics industries.

[0003] In the production process of diode diffusers, more than ten cleaning processes are required from wafer to finished diffuser, and IPA dehydration is required after each cleaning to ensure the cleanliness and dryness of the silicon wafer surface. As an indispensable dehydration solvent in the diode industry, the consumption of IPA will directly affect the cost of the entire diode diffuser production process. Therefore, whether from the perspective of energy conservation and emission reduction or from the perspective of production cost control, a new solution that can effectively control the IPA consumption cost is needed.

[0004] The traditional old IPA dehydration device can only dehydrate silicon wafers, and the used IPA dehydrating agent can only be recycled and sent out for treatment, which leads to high costs and serious waste. In this context, how to recycle and reuse IPA in the production process of diode diffusers is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art and provide an automatic silicon wafer dehydration device with IPA recovery and recycling function.

[0006] The specific technical solutions adopted by the present invention are as follows:

[0007] An automatic silicon wafer dehydration device with IPA recycling and use comprises a basket device for storing silicon wafers and a silicon wafer dehydration tank for IPA dehydration, wherein the silicon wafer dehydration tank is divided into a primary dehydration tank and a secondary dehydration tank, wherein the primary dehydration tank and the secondary dehydration tank are connected via a stepped overflow structure, and the overflow direction is from the primary dehydration tank to the secondary dehydration tank; a liquid outlet is provided at the bottom of the primary dehydration tank, the liquid outlet is connected to a distillation device for temperature-controlled distillation of IPA waste liquid via a pipeline with a first one-way valve, a gas phase outlet of the distillation device is connected to an inlet of a drying cylinder for adsorbing water vapor via a pipeline with a second one-way valve, the outlet of the drying cylinder is connected to an inlet of a condensation cylinder for condensing dry IPA steam via a pipeline with a third one-way valve, and the liquid phase outlet of the condensation cylinder is connected to a collection container via a pipeline with a fourth one-way valve.

[0008] Preferably, a stirring heater is provided in the distillation device, a stirring motor of the stirring heater is arranged outside the shell of the distillation device, a stirring blade thereof extends into the inner cavity of the distillation device, and a heating element is provided on the stirring blade.

[0009] Preferably, a temperature control device is provided in the distillation device, and the temperature control device is connected to a temperature measuring probe and a heating element inside the distillation device to form temperature feedback control.

[0010] Preferably, the flower basket carrying device comprises a driving device and a flower basket handle, wherein the flower basket handle is connected to a displacement output end of the driving device and moves in and out of the primary dewatering tank and the secondary dewatering tank under the drive of the driving device.

[0011] Preferably, the flower basket handle consists of a supporting plate for placing the flower basket and a handle located in the middle of the supporting plate, and the displacement output end of the driving device is connected to the handle.

[0012] Preferably, the supporting plate of the flower basket handle should be large enough to accommodate a single row or double row of flower baskets.

[0013] Preferably, the flower basket handle is made of Teflon.

[0014] Preferably, the supporting plate in the flower basket handle is a hollow plate.

[0015] Preferably, the stepped overflow structure includes two vertical impermeable partitions, which divide the silicon wafer dewatering trough into a primary dewatering trough and a secondary dewatering trough. The bottom of the first partition close to the primary dewatering trough is spaced apart from the bottom surface of the silicon wafer dewatering trough to allow water to flow through, and the bottom of the second partition close to the secondary dewatering trough is fitted with the bottom surface of the silicon wafer dewatering trough to prevent water from flowing through, and the top elevation of the first partition is higher than the top of the second partition, thereby clamping a one-way overflow channel connecting the dewatering troughs on both sides between the two partitions.

[0016] Preferably, the driving device is driven by a servo motor.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The utility model is based on the IPA recycling and utilization method, which ensures the utilization rate of IPA. The two-stage dehydration of the graded dehydration tank can fully reduce the impurities and water adhesion on the surface of the silicon wafer, ensuring the dehydration success rate. The stepped overflow structure can fully ensure that the IPA content in the secondary dehydration tank is always greater than that in the primary dehydration tank, which can effectively ensure the dehydration effect. The IPA distillation recovery device can recover as much IPA dehydrating agent as possible, reduce production costs, and save energy and reduce consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of an automatic silicon wafer dehydration device with IPA recovery and circulation.

[0020] Figure 2 Schematic diagram of the structure of a traditional silicon wafer dehydration device.

[0021] Figure 3 for Figure 1 Schematic diagram of the overflow channel flow direction of the silicon wafer dewatering tank.

[0022] Figure 4 This is a schematic diagram of the structure of the automatic silicon wafer dehydration device with double-row flower baskets.

[0023] The reference numerals in the figure are: driving device 1, flower basket handle 2, second partition 3, first one-way valve 6, first partition 7, temperature control device 8, distillation device 9, stirring heater 10, second one-way valve 11, drying cylinder 12, third one-way valve 13, condensing cylinder 14, fourth one-way valve 15, collecting container 16. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0025] In the description of the present invention, it is to be understood that when an element is considered to be "connected" to another element, it may be directly connected to the other element or indirectly connected, that is, there are intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0026] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for the purpose of distinguishing descriptions, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0027] like Figure 1 As shown, in a preferred embodiment of the present invention, an automatic silicon wafer dehydration device with IPA recycling is provided, the automatic silicon wafer dehydration device comprises a basket device for storing silicon wafers and a silicon wafer dehydration tank for IPA dehydration. Figure 2 As shown, the inner cavity of the tank body is divided into a primary dehydration tank 4 and a secondary dehydration tank 5 by a partition, and the bottom of the partition is in contact with the bottom of the tank, so water cannot flow through it. Generally, there is no liquid medium exchange between the primary dehydration tank 4 and the secondary dehydration tank 5. However, in the silicon wafer dehydration tank of the present invention, the traditional partition is improved, and a stepped overflow structure is used to replace the partition. The primary dehydration tank 4 and the secondary dehydration tank 5 are connected by a stepped overflow structure, and the stepped overflow structure forms a one-way overflow channel from the primary dehydration tank 4 to the secondary dehydration tank 5, and the overflow direction is from the primary dehydration tank 4 to the secondary dehydration tank 5. The flow direction is as shown in FIG. Figure 3 As shown. The stepped overflow structure includes two vertical impermeable partitions, which divide the silicon wafer dewatering trough into a primary dewatering trough 4 and a secondary dewatering trough 5. Both sides of the two partitions are in contact with the side of the silicon wafer dewatering trough and water cannot flow through. However, the bottom of the first partition 7 near the primary dewatering trough 4 is spaced from the bottom of the silicon wafer dewatering trough to allow water to flow through, while the bottom of the second partition 3 near the secondary dewatering trough 5 is in contact with the bottom of the silicon wafer dewatering trough and water cannot flow through. The top elevation of the first partition 7 is higher than the top of the second partition 3, so that a one-way overflow channel connecting the dewatering troughs on both sides is formed between the two partitions. Therefore, when the liquid medium in the secondary dewatering trough 5 exceeds the top of the second partition 3, it can flow into the primary dewatering trough 4 from the one-way overflow channel.

[0028] When in use, isopropyl alcohol (IPA) is pre-injected into the first-level dehydration tank 4 and the second-level dehydration tank 5 to replace the water film on the surface of the silicon wafer. The IPA dehydration process of semiconductor silicon wafers belongs to the prior art, so how to achieve dehydration in the dehydration tank is not repeated. When the silicon wafer is placed in the flower basket and the surface is cleaned and taken out in the ultrasonic cleaning device, the silicon wafer has water on its surface, so the silicon wafer can be placed directly on the flower basket basket device together with the flower basket, first immersed in the first-level dehydration tank 4 for the first dehydration, and then taken out and immersed in the second-level dehydration tank 5 for dehydration after the first dehydration is completed. In the two dehydration processes, a part of IPA has been suspended on the surface of the silicon wafer after the first dehydration, and the moisture content decreases, so the IPA originally in the first-level dehydration tank 4 is further brought into the second-level dehydration tank 5 during the second dehydration. After the second-level dehydration tank 5 is full, it can overflow into the first-level dehydration tank 4 through the stepped overflow structure, and the IPA recovery is carried out in combination with the subsequent IPA recovery device. Under the one-way overflow control of the stepped overflow structure, the stepped overflow structure can fully ensure that the IPA content in the secondary dehydration tank is always greater than that in the primary dehydration tank, which can effectively ensure the dehydration effect.

[0029] The flower basket lifting device in the present invention can be used as long as it can place the flower basket, and its entry and exit in the two dewatering tanks can be carried out by automated equipment or manually. In an embodiment of the present invention, an automated implementation form is provided, and the flower basket lifting device includes a driving device 1 and a flower basket handle, and the flower basket handle is connected to the displacement output end of the driving device 1, and enters and exits the primary dewatering tank 4 and the secondary dewatering tank 5 under the drive of the driving device 1. The driving device 1 can be a mechanical arm, a three-dimensional positioning mechanism or other equipment, as long as it can drive the flower basket handle to move up, down, left and right. In an embodiment of the present invention, the driving device 1 is driven by a servo motor, and its driving direction should include up and down lifting and left and right displacement, so as to ensure that the flower basket lifting device can complete IPA dehydration in the primary dewatering tank 4 and the secondary dewatering tank 5 in sequence. The servo motor can cooperate with a screw rod, a slider, etc. to realize the drive of the flower basket lifting device, and there is no restriction on this.

[0030] In the present invention, at least one flower basket handle is required to achieve the corresponding function, and of course, multiple flower basket handles may be provided at the same time. In addition, the flower basket handle may be in various forms, and any flower basket handle in the prior art may achieve similar functions. In an embodiment of the present invention, the flower basket handle is composed of a support plate for placing a flower basket and a handle located in the middle of the support plate, and the displacement output end of the drive device 1 is connected to the handle. The flower basket handle is preferably made of Teflon material to ensure corrosion resistance. The size of the support plate of the flower basket handle should be sufficient to accommodate a single row or double row of flower baskets, for example, see Figure 4 As shown, the flower basket placement area around the handle is preferably configured to accommodate 8 double-row baskets.

[0031] The following is a further introduction to the IPA recovery device installed below the silicon wafer dehydration tank.

[0032] Continue to see Figure 1 As shown, in the utility model, a liquid outlet is provided at the bottom of the primary dehydration tank 4, and the liquid outlet is connected to the distillation device 9 through a pipeline with a first one-way valve 6. The distillation device 9 is used to perform temperature-controlled distillation on the IPA waste liquid, which can be implemented by using common distillation equipment, as long as temperature-controlled distillation can be achieved. In an embodiment of the present invention, a stirring heater 10 is provided on the closed shell of the distillation device 9, and the stirring heater 10 is composed of a stirring motor and a stirring blade. The stirring motor is arranged outside the shell of the distillation device 9, and its output shaft is connected to the stirring blade. The stirring blade extends into the inner cavity of the distillation device 9, and the stirring blade is provided with a heating element. The heating element can be built into the blade and electrically heated, or it can be attached to the surface of the blade as an auxiliary element. In addition, it is best to provide a temperature control device 8 in the distillation device 9, and the temperature control device 8 can be implemented by a single-chip microcomputer, an MCU or other mature temperature control modules. A temperature probe for measuring the inner cavity temperature can be installed inside the distillation device 9. The temperature control device 8 is connected to the temperature probe and the heating element inside the distillation device 9 to form a temperature feedback control, thereby accurately adjusting the distillation temperature according to demand, and can achieve heating while stirring, so that the internal IPA is evenly heated and volatilization is accelerated.

[0033] The distillation device 9 in the present invention is preferably arranged below the primary dehydration tank, so that the internal liquid medium can flow downward by gravity. After distillation, the distillation device 9 converts both water and IPA into gaseous state and discharges them from the gas phase outlet. The gas phase outlet of the distillation device 9 is connected to the inlet of the drying cylinder 12 for adsorbing water vapor through a pipeline with a second one-way valve 11. The interior of the drying cylinder 12 can be filled with a desiccant that can specifically adsorb water but cannot adsorb IPA, so that the water vapor escaping with IPA is adsorbed by the desiccant to ensure that the recovered IPA has a sufficiently low water content and meets the use standard. After passing through the drying cylinder 12, pure IPA gas is output, and the outlet of the drying cylinder 12 is connected to the inlet of the condensing cylinder 14 for condensing the dry IPA vapor through a pipeline with a third one-way valve 13. The condensing cylinder 14 has a built-in refrigeration component, and its refrigeration temperature needs to be lower than the condensation temperature of the IPA vapor, so as to convert the IPA from gas to liquid. The condensation cylinder 14 re-condenses the atomized IPA into liquid form by low-temperature condensation, and the liquid phase outlet of the condensation cylinder 14 is connected to the collection container 16 through a pipeline with a fourth one-way valve 15. Finally, the liquid pure IPA is stored in the collection container 16 again to achieve repeated recycling.

[0034] It can be seen that the automatic silicon wafer dehydration device with IPA recovery and recycling of the present invention can recover as much IPA dehydrating agent as possible, reduce production costs, and save energy and reduce consumption.

[0035] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. An automatic silicon wafer dehydration device with IPA recovery and recycling, comprising a basket device for storing silicon wafers and a silicon wafer dehydration tank for IPA dehydration, wherein the silicon wafer dehydration tank is divided into a primary dehydration tank (4) and a secondary dehydration tank (5), characterized in that: The primary dehydration tank (4) and the secondary dehydration tank (5) are connected via a stepped overflow structure, and the overflow direction is from the primary dehydration tank (4) to the secondary dehydration tank (5); a liquid outlet is provided at the bottom of the primary dehydration tank (4), and the liquid outlet is connected to a distillation device (9) for temperature-controlled distillation of IPA waste liquid through a pipeline with a first one-way valve (6); the gas phase outlet of the distillation device (9) is connected to the inlet of a drying cylinder (12) for adsorbing water vapor through a pipeline with a second one-way valve (11); the outlet of the drying cylinder (12) is connected to the inlet of a condensation cylinder (14) for condensing dry IPA vapor through a pipeline with a third one-way valve (13); and the liquid phase outlet of the condensation cylinder (14) is connected to a collection container (16) through a pipeline with a fourth one-way valve (15).

2. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 1, characterized in that: The distillation device (9) is provided with a stirring heater (10), a stirring motor of the stirring heater (10) is arranged outside the shell of the distillation device (9), a stirring blade thereof extends into the inner cavity of the distillation device (9), and a heating element is provided on the stirring blade.

3. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 2, characterized in that: The distillation device (9) is provided with a temperature control device (8), and the temperature control device (8) is connected to a temperature measuring probe and a heating element inside the distillation device (9) to form temperature feedback control.

4. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 1, characterized in that: The flower basket lifting device comprises a driving device (1) and a flower basket handle, wherein the flower basket handle is connected to a displacement output end of the driving device (1) and moves in and out of a primary dewatering trough (4) and a secondary dewatering trough (5) under the drive of the driving device (1).

5. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 4, characterized in that: The flower basket handle consists of a supporting plate for placing the flower basket and a handle located in the middle of the supporting plate, and the displacement output end of the driving device (1) is connected to the handle.

6. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 5, characterized in that: The supporting plate of the flower basket handle should be large enough to accommodate single-row or double-row flower baskets.

7. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 4, characterized in that: The flower basket handle is made of Teflon material.

8. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 4, characterized in that: The supporting plate in the handle of the flower basket is a hollow plate.

9. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 1, characterized in that: The stepped overflow structure comprises two vertical impermeable partitions, which divide the silicon wafer dewatering trough into a primary dewatering trough (4) and a secondary dewatering trough (5); the bottom of the first partition (7) close to the primary dewatering trough (4) is spaced from the bottom surface of the silicon wafer dewatering trough to allow water to flow through; the bottom of the second partition (3) close to the secondary dewatering trough (5) is in contact with the bottom surface of the silicon wafer dewatering trough to prevent water from flowing through; and the top elevation of the first partition (7) is higher than the top elevation of the second partition (3), so that a one-way overflow channel connecting the dewatering troughs on both sides is formed between the two partitions.

10. The automatic silicon wafer dehydration device with IPA recovery and recycling as claimed in claim 4, characterized in that: The driving device (1) is driven by a servo motor.

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