Silicon wafer cleaning equipment

Abstract

The silicon wafer cleaning equipment comprises a rough cleaning tank, a first medicament tank, a first pure water tank, a second medicament tank, a second pure water tank, a bubble water tank and a third pure water tank which are sequentially distributed in a first direction, tap water is added into the rough cleaning tank; pure water, an alkaline agent and a surfactant are added into the first medicament tank; pure water, an alkaline agent and hydrogen peroxide are added into the second medicament tank; pure water is added into the first pure water tank, the second pure water tank and the third pure water tank; a plurality of bubble water tanks are sequentially distributed and are sequentially communicated in an overflow manner, the overflow direction is in a second direction, a bubble generator is arranged in each bubble water tank and is used for providing millimeter-level bubbles, and the bubbles can adsorb impurities in water under the action of a surfactant, and can adsorb the impurities in the water under the action of overflow water. And the water can be cleaned, the occurrence rate of dirt pieces is reduced, the period of changing water and chemicals is prolonged, and the dosage of pure water and chemicals is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of silicon wafer production, and in particular to silicon wafer cleaning equipment. Background Art

[0002] After the silicon wafer slicer cuts the silicon rod into slices, the silicon wafer needs to be removed from the resin plate through a degumming process, and then cleaned in a cleaning machine using chemicals such as hydrogen peroxide, sodium hydroxide, and potassium hydroxide. In the prior art, silicon wafers are generally cleaned through 3 chemical tanks and 8 pure water tanks, which requires a large amount of pure water and chemicals. After a long period of cleaning, the impurities in the water increase, and dirty slices are prone to appear at the end of the cleaning cycle. The water change cycle is short, resulting in a large amount of pure water and chemicals, and a decrease in production capacity. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a silicon wafer cleaning device that can reduce the incidence of wafer contamination and reduce the amount of pure water and chemicals used.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: a silicon wafer cleaning equipment, comprising a primary washing tank, a first chemical tank, a first pure water tank, a second chemical tank, a second pure water tank, a bubble water tank and a third pure water tank distributed in sequence along a first direction; tap water is added to the primary washing tank; pure water, alkali agent and surfactant are added to the first chemical tank; pure water, alkali agent and hydrogen peroxide are added to the second chemical tank; pure water is added to the first pure water tank, the second pure water tank and the third pure water tank; there are multiple bubble water tanks distributed in sequence, the multiple bubble water tanks are connected in sequence by overflow, and the overflow direction is along the second direction, and each bubble water tank is provided with a bubble generator, the bubble generator is used to provide millimeter-level bubbles, the bubbles can absorb impurities in water under the action of surfactant, and enter other bubble water tanks in sequence under the action of overflow water; wherein the first direction is the direction along the cleaning sequence, and the second direction is opposite to the first direction.

[0005] Compared with the prior art, the beneficial effect of the present invention is that: the silicon wafer cleaning equipment is provided with a bubble water tank, and the bubble generator in the bubble water tank can provide millimeter-sized bubbles, which are almost not annihilated when rising in the water, and most of them will merge with other bubbles into a larger bubble. Since the silicon wafer enters the bubble water tank after being cleaned by the front-end reagent, the surfactant residue carried by the silicon wafer will be integrated into the bubble water, and the bubbles will absorb impurities such as silicon powder and organic matter in the water under the action of the surfactant. Under the action of overflow water, the bubbles with impurities adsorbed on the surface will be taken away and enter other bubble water tanks in turn. After entering the last bubble water tank, they can be discharged by overflow or other means. The bubble water tank of the silicon wafer cleaning equipment is arranged after the first reagent tank and the second reagent tank. After the silicon wafer is cleaned with the reagent, it is cleaned with bubble water. Since the bubbles can take away the impurities in the bubble water tank, the impurity content in the water in the bubble water tank is relatively low, and the impurity content in the water in the bubble water tank is lower as it is closer to the end of the cleaning tank. This can not only effectively improve the cleaning effect at the end of the cleaning tank, but also effectively reduce the occurrence rate of dirty wafers at the end of the cleaning cycle. Since the occurrence rate of dirty wafers is reduced, the water change cycle can also be extended, which greatly reduces the consumption of pure water and reagents. While improving production capacity, it can also reduce costs.

[0006] In the above-mentioned silicon wafer cleaning equipment, the second pure water tank is connected to a bubble water tank closest to it by overflow, so that the water in the bubble water tank enters the second pure water tank.

[0007] In the above-mentioned silicon wafer cleaning equipment, the second pure water tank is connected to the primary cleaning tank.

[0008] In the above-mentioned silicon wafer cleaning equipment, the second pure water tank is connected to the primary washing tank by means of a pipeline and overflow.

[0009] In the above-mentioned silicon wafer cleaning equipment, the third pure water tank is connected to a bubble water tank closest to it, so that the water in the third pure water tank enters the bubble water tank.

[0010] In the above-mentioned silicon wafer cleaning equipment, there are two first reagent tanks distributed continuously, and the two first reagent tanks are independent of each other.

[0011] In the above-mentioned silicon wafer cleaning equipment, there are three bubble water tanks distributed continuously.

[0012] In the above-mentioned silicon wafer cleaning equipment, there are two third pure water tanks distributed continuously, and the two third pure water tanks are connected by overflow, and the overflow direction is along the second direction.

[0013] In the above silicon wafer cleaning equipment, the diameter D of the bubbles satisfies: 1 μm<D<1 cm.

[0014] In the above-mentioned silicon wafer cleaning equipment, the density N of the bubbles satisfies: 100,000 / cubic meter<N<50,000,000 / cubic meter.

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a silicon wafer cleaning device according to an embodiment of the present invention.

[0017] Explanation of the accompanying figures: 100 primary washing tank, 200 first medicine tank, 300 first pure water tank, 400 second medicine tank, 500 second pure water tank, 600 bubble water tank, 700 third pure water tank. DETAILED DESCRIPTION

[0018] Reference Figure 1 The present invention provides a silicon wafer cleaning device, comprising a primary cleaning tank 100, a first reagent tank 200, a first pure water tank 300, a second reagent tank 400, a second pure water tank 500, a bubble water tank 600 and a third pure water tank 700, which are sequentially distributed along a first direction; tap water is added to the primary cleaning tank 100; pure water, alkaline agent and surfactant are added to the first reagent tank 200; pure water, alkaline agent and hydrogen peroxide are added to the second reagent tank 400; the first pure water tank 300, the second pure water tank 500 and the third pure water tank 700 are added to the first reagent tank 200; the first pure water tank 300, the second pure water tank 500 and the third pure water tank 70 ... Pure water is added to the tanks 700; there are multiple bubble water tanks 600 distributed in sequence, and the multiple bubble water tanks 600 are connected in sequence by overflow, and the overflow direction is along the second direction, and each bubble water tank 600 is provided with a bubble generator, and the bubble generator is used to provide millimeter-level bubbles. The bubbles can absorb impurities in the water under the action of surfactants, and enter other bubble water tanks 600 in sequence under the action of overflow water; wherein, the first direction is the direction along the cleaning order, and the second direction is opposite to the first direction.

[0019] The silicon wafer cleaning equipment is provided with a bubble water tank 600. The bubble generator in the bubble water tank 600 can provide millimeter-sized bubbles. These millimeter-sized bubbles will hardly disappear when rising in the water, and most of them will merge with other bubbles into a larger bubble. Since the silicon wafer enters the bubble water tank 600 after being cleaned by the front-end reagent, the surfactant residue carried by the silicon wafer will be integrated into the bubble water. Since impurities such as silicon powder are hydrophobic, and the surfactant is amphiphilic, one end is hydrophilic and the other end is hydrophobic, therefore, the bubbles will absorb impurities such as silicon powder and organic matter in the water under the action of the surfactant. Under the action of the overflow water, the bubbles with impurities adsorbed on the surface will be taken away and enter other bubble water tanks 600 in turn. After entering the last bubble water tank 600, they can be discharged by overflow or the like. The bubble water tank 600 of the silicon wafer cleaning equipment is arranged after the first reagent tank 200 and the second reagent tank 400. After the silicon wafer is cleaned with the reagent, it is cleaned with bubble water. Since the bubbles can take away impurities in the bubble water tank 600, the impurity content in the water in the bubble water tank 600 is relatively low, and the impurity content in the water in the bubble water tank 600 is lower as it is closer to the end of the cleaning tank. This can not only effectively improve the cleaning effect at the end of the cleaning tank, but also effectively reduce the occurrence rate of dirty wafers at the end of the cleaning cycle. Since the occurrence rate of dirty wafers is reduced, the water change cycle can also be extended, greatly reducing the consumption of pure water and reagents, while improving production capacity, it can also reduce costs.

[0020] Example

[0021] Reference Figure 1 , an embodiment of the present invention provides a silicon wafer cleaning device, comprising a primary washing tank 100, a first reagent tank 200, a first pure water tank 300, a second reagent tank 400, a second pure water tank 500, a bubble water tank 600 and a third pure water tank 700 sequentially distributed along a first direction. In this embodiment, there are two first reagent tanks 200 distributed continuously, three bubble water tanks 600 distributed continuously, and two third pure water tanks 700 distributed continuously. Therefore, along the first direction, the sequentially distributed tank bodies are named as follows: the primary washing tank 100 is tank No. 1, the two first reagent tanks 200 are tank No. 2 and tank No. 3, respectively, the first pure water tank 300 is tank No. 4, the second reagent tank 400 is tank No. 5, the second pure water tank 500 is tank No. 6, the three bubble water tanks 600 are tank No. 7, tank No. 8 and tank No. 9, respectively, and the two third pure water tanks 700 are tank No. 10 and tank No. 11, respectively. Tanks No. 2 and No. 3 are independent of each other, and tanks No. 6, No. 7, No. 8, No. 9, No. 10 and No. 11 are connected in sequence by overflow, among which the pure water in tank No. 11 overflows to tank No. 10, the pure water in tank No. 10 overflows to tank No. 9, the bubble water in tank No. 9 overflows to tank No. 8, the bubble water in tank No. 8 overflows to tank No. 7, the bubble water in tank No. 7 overflows to tank No. 6, and the bubble water in tank No. 6 overflows to tank No. 1.

[0022] Tap water is added to tank No. 1 to pre-clean the residual reagents and silicon powder on the surface of the silicon wafer. The water in tank No. 1 comes from the tap water added initially and the water in tank No. 6. Among them, tank No. 1 is connected to tank No. 6 through a water pipe and overflow, which can not only allow the bubble water carrying impurities in tank No. 6 to overflow to tank No. 1, but also allow the sewage in tank No. 6 to flow into tank No. 1 through the water pipe. The water in tank No. 1 is discharged by overflow. Since tank No. 1 is used to pre-clean the silicon wafer, the water carrying impurities entering tank No. 1 from tank No. 6 will hardly have a negative impact on the overall cleaning effect. The water carrying impurities discharged from tank No. 6 into tank No. 1 can not only discharge and renew the water in tank No. 6, but also be reused in tank No. 1, further reducing water consumption.

[0023] Pure water, alkaline agents and surfactants are added to tank No. 2 to react and clean the silicon powder on the surface of the silicon wafer. When the agent needs to be changed, all the solutions in tank No. 2 should be drained.

[0024] Pure water, alkaline reagents and surfactants are added to the No. 3 tank to react and clean the silicon powder on the surface of the silicon wafer. When the reagent needs to be changed, the solution in the No. 3 tank is completely drained. After two cleanings in the No. 2 and No. 3 tanks, the cleaning effect of the silicon wafer can be greatly improved.

[0025] The water in tank No. 4 comes from the pure water added initially, and is completely emptied when changing water or chemicals. After the silicon wafers are cleaned twice with chemicals in tanks No. 2 and No. 3, they are cleaned with pure water in tank No. 4 to clean the chemical residues and other substances on the surface of the silicon wafers, thereby reducing the chemical concentration on the surface of the silicon wafers.

[0026] Pure water, alkaline reagents and hydrogen peroxide are added to tank No. 5 to react and clean the metal ions on the surface of the silicon wafer. The water in tank No. 5 is completely drained when changing water or reagents.

[0027] Pure water is added to tank No. 6 to clean the residue on the surface of the silicon wafer. The water in tank No. 6 comes from the initially added pure water and the bubble water overflowing from tank No. 7. The water in tank No. 6 is discharged into tank No. 1 through overflow and water pipes, and is completely emptied when changing water or reagents.

[0028] Pure water is added to tank No. 7, and a bubble generator is installed in tank No. 7, which can provide millimeter-level bubbles to absorb impurities in the water under the action of surfactants, and make the bubbles rise to the water surface, continuously absorb impurities in the water, and discharge them into tank No. 6 by overflow. When changing water and reagents, the water in tank No. 7 should be completely emptied.

[0029] Pure water is added to the No. 8 tank, and a bubble generator is installed in the No. 8 tank, which can provide millimeter-level bubbles to absorb impurities in the water under the action of surfactants, and make the bubbles rise to the water surface, continuously absorb impurities in the water, and discharge them into the No. 7 tank by overflow. When changing water and reagents, the water in the No. 8 tank should be completely emptied.

[0030] Pure water is added to the No. 9 tank, and a bubble generator is installed in the No. 9 tank, which can provide millimeter-sized bubbles to absorb impurities in the water under the action of surfactants, and make the bubbles rise to the water surface, continue to absorb impurities in the water, and discharge them into the No. 8 tank by overflow. When changing water and reagents, the water in the No. 9 tank is completely emptied. After the bubble water cleaning of the three tanks of No. 7, No. 8 and No. 9, the concentration of the reagent on the surface of the silicon wafer is continuously reduced, and the cleaning effect is gradually enhanced.

[0031] Pure water is added to tanks 10 and 11 to clean the surface of the silicon wafer in the final step. The water in tank 10 comes from the pure water added at the beginning and the water overflowing from tank 11 to make full use of the water. The water in tank 10 flows into tank 9 by overflow. When changing water or reagents, all the water in tank 10 is drained. The water in tank 11 comes from the pure water added at the beginning and the pure water that is continuously injected. The water in tank 11 flows into tank 10 by overflow. When changing water or reagents, the injection of pure water is stopped and all the water in tank 11 is drained.

[0032] In tanks 7, 8 and 9, when the bubbles rise in the water body, most of them will merge into a larger bubble and absorb impurities in the water body during the rising process. In the rising process, due to the resistance of the water, the adsorbed impurities will slide to the water-avoiding surface of the bubble. After rising to the water surface, the impurities will fall at the junction of the bubble and the water surface, and enter the next tank with the dirt under the action of the overflow water.

[0033] Furthermore, the diameter D of the bubble satisfies: 1μm<D<1cm. The bubbles within this range are large and small, but generally within the millimeter level. When the bubbles rise in the water body, a small number of small bubbles may burst, but the impact force generated by the bursting will also take away the impurities on the surface of the silicon wafer. Most of the bubbles will not disappear during the rising process, but will merge with other bubbles into a larger bubble, which will adsorb silicon powder, organic matter and other pollutants under the action of surfactants in the water. And after the bubbles rise to the surface of the water body, due to the action of surfactants, the bubbles will exist for a long time and can take away the pollutants with the overflow water. Further, the density N of the bubbles satisfies: 100,000 / cubic meter<N<50 million / cubic meter. Further, the size of the bubbles can be adjusted by adjusting the air pump power of the bubble generator and adjusting the strength of the bubble generator.

[0034] Assume that the production capacity of the silicon wafer cleaning equipment is M / 24h, the average diameter of the bubbles is d, the area of ​​the water pool is S, the allowable bubble area of ​​the water surface is η, the water flow rate is V, the amount of dirt carried by each silicon wafer is X, the average diameter of the dirt particles is Y, the conventional water replacement cycle is T1, the existing water replacement cycle is T2, the periodic water replacement downtime is T3, the volume of each water tank is L, the number of pure water tanks is Z, and the number of saturated dirt in the pure water tank is P. Then, there is the following relationship:

[0035] M*T1 / X=Z-1*P;

[0036] The number of bubbles allowed on the water surface = S*η / π*d;

[0037] The number of particles carried by each bubble = π*d / Y;

[0038] The amount of dirt overflow per unit time = S*η / π*d*π*d / Y*V

[0039] =S*η*V / Y;

[0040] Conventional dirt retention = M / 24*3600*Z-1-S*η*V / Y;

[0041] Saturated dirt volume per tank = M*T1 / X / Z-1

[0042] =M*T1 / [X*Z-1];

[0043] The current dirt retention in each tank = [M / 24*3600*Z-1-S*η*V / Y]-S*η*V / Y

[0044] =M / 24*3600*Z-1-2*S*η*V / Y;

[0045] Existing water replacement cycle T2 = {M*T1 / [X*Z-1]} / M / 24*3600*Z-1-2*S*η*V / Y;

[0046] Conventional water replacement cycle T1 = Z-1*P*X / M;

[0047] Water saving rate = T2-T1 / T1

[0048] =[M*YT1*24*3600-2*S*η*V*X / Z-1*P*X*X*Y]-1;

[0049] Water saving = {[M*YT1*24*3600-2*S*η*V*X / Z-1*P*X*X*Y]-1}*11L;

[0050] Capacity increase = {[M*YT1*24*3600-2*S*η*V*X / Z-1*P*X*X*Y]-1}*T3*M.

[0051] In this embodiment, the number of water tanks is consistent with that used in the prior art, that is, eleven water tanks. According to the above calculation method, the data of the amount of pure water, the amount of chemical solution, and the incidence rate of dirty pieces in this embodiment are compared with those in the prior art as shown in the following table:

[0052]

[0053] In the above table, the prior art is before improvement, and the present embodiment is after improvement. From the data comparison in the above table, it can be seen that the cleaning tank in the present embodiment can improve the production capacity, reduce the occurrence rate of dirty pieces, and extend the cleaning cycle, thereby greatly reducing the amount of pure water and chemicals used.

[0054] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and cannot be understood as a limitation on the present invention.

[0055] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0056] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0057] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A silicon wafer cleaning device, characterized in that: It comprises a primary washing tank (100), a first reagent tank (200), a first pure water tank (300), a second reagent tank (400), a second pure water tank (500), a bubble water tank (600) and a third pure water tank (700) which are sequentially distributed along a first direction; Tap water is added into the primary washing tank (100); Pure water, alkaline agent and surfactant are added into the first reagent tank (200); The second reagent tank (400) is filled with pure water, alkaline agent and hydrogen peroxide; Pure water is added to the first pure water tank (300), the second pure water tank (500) and the third pure water tank (700); The bubble water tanks (600) are distributed in a plurality, and the plurality of bubble water tanks (600) are connected in a sequence by overflow, and the overflow direction is along the second direction. A bubble generator is provided in each bubble water tank (600), and the bubble generator is used to provide millimeter-level bubbles. The bubbles can absorb impurities in water under the action of a surfactant, and enter other bubble water tanks (600) in sequence under the action of overflow water. The first direction is a direction along the cleaning sequence, and the second direction is opposite to the first direction.

2. The silicon wafer cleaning equipment according to claim 1, characterized in that: The second pure water tank (500) is connected to a bubble water tank (600) closest to it by overflow, so that the water in the bubble water tank (600) enters the second pure water tank (500).

3. The silicon wafer cleaning equipment according to claim 2, characterized in that: The second pure water tank (500) is connected to the primary washing tank (100).

4. The silicon wafer cleaning equipment according to claim 3, characterized in that: The second pure water tank (500) is connected to the primary washing tank (100) by means of a pipeline and overflow.

5. The silicon wafer cleaning equipment according to claim 1, characterized in that: The third pure water tank (700) is connected to a bubble water tank (600) that is closest to it, so that the water in the third pure water tank (700) can enter the bubble water tank (600).

6. The silicon wafer cleaning equipment according to claim 1, characterized in that: There are two first medicine slots (200) distributed continuously, and the two first medicine slots (200) are independent of each other.

7. The silicon wafer cleaning equipment according to claim 1, characterized in that: The bubble water tanks (600) are distributed in three in succession.

8. The silicon wafer cleaning equipment according to claim 1, characterized in that: There are two third pure water tanks (700) distributed continuously, and the two third pure water tanks (700) are connected by overflow, and the overflow direction is along the second direction.

9. The silicon wafer cleaning equipment according to claim 1, characterized in that: The diameter D of the bubbles satisfies: 1 μm<D<1 cm.

10. The silicon wafer cleaning equipment according to claim 1, characterized in that: The density N of the bubbles satisfies: 100,000 / cubic meter < N < 50,000,000 / cubic meter.

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