Equipment and method for grooving after printing a mask in a single-sided electroplating process

Abstract

The present invention provides an apparatus and method for grooving after printing a mask in a single-sided electroplating process, including: a water vapor chamber, a first drying chamber, an acidic gas chamber, a first pure water cleaning tank, an alkali cleaning tank, a second pure water cleaning tank, and a second drying chamber that are sequentially arranged for processing silicon wafers; conveying rollers are arranged in the water vapor chamber, the first drying chamber, the acidic gas chamber, the first pure water cleaning tank, the alkali cleaning tank, the second pure water cleaning tank, and the second drying chamber, and the conveying rollers are configured to place and transport silicon wafers. The beneficial effect of the present invention is that the passivation film in the area not covered by the mask is removed by gaseous acid mist, thereby greatly reducing the requirement of the mask material for acid resistance; the HF gas will dissolve into the part of the silicon wafer where water is present to form HF, and HF corrodes the passivation film. The corrosion rate can be controlled by controlling the dissolution amount of HF, and the amount of acid released can be relatively accurately controlled, reducing the consumption of acid.

Description

Technical Field

[0001] The present invention belongs to the field of electroplating of solar cells, and particularly relates to an apparatus and method for grooving after printing a mask in a single-sided electroplating process. Background Art

[0002] In existing electroplating processes, the use of masks is relatively common. Generally, a photosensitive or thermosensitive material that is acid-resistant but alkali-insensitive is printed. The pattern of the material is the same as the grid line pattern to be electroplated, and it is cured under certain temperature or light conditions. Then, the silicon wafer is placed in a specific acid solution to remove the passivation film in the area not covered by the mask material, while the area covered by the mask remains unaffected. Then, through an alkali solution or other specific cleaning solutions, the mask layer material is removed, so that the silicon material itself is exposed at the grid line pattern position and can be electroplated, while other areas are covered by film layers such as passivation films and cannot be electroplated. The difficulty in the existing technical solutions is that the mask material is likely to fall off when soaked in the acid solution, resulting in the film in the area covered by the mask being corroded by the acid solution, and the effect of the mask cannot be achieved. Summary of the Invention

[0003] The problem to be solved by the present invention is to provide an apparatus and method for grooving after printing a mask in a single-sided electroplating process, which is particularly suitable for removing passivation films such as silicon nitride in the area not covered by the mask material after printing the mask.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is: An apparatus for grooving after printing a mask in a single-sided electroplating process, characterized by comprising: a steam chamber, a first drying chamber, an acidic gas chamber, a first pure water cleaning tank, an alkali cleaning tank, a second pure water cleaning tank, and a second drying chamber that are sequentially arranged for processing silicon wafers;

[0005] Conveyor rollers are provided in the steam chamber, the first drying chamber, the acidic gas chamber, the first pure water cleaning tank, the alkali cleaning tank, the second pure water cleaning tank, and the second drying chamber, and the conveyor rollers are configured to place and transport silicon wafers.

[0006] Further, a plurality of steam generators and injection nozzles are provided in the steam chamber, the injection nozzles are configured to inject steam onto the surface of the silicon wafer, and the amount of the steam ejected from the injection nozzles is adjustable.

[0007] Further, at least one water absorption roller that cooperates with the conveyor roller is provided at the connection between the steam chamber and the first drying chamber.

[0008] Further, at least one of the water absorption rollers that cooperate with the conveyor roller is provided at the connection between the first drying chamber and the steam chamber for removing excess moisture on the mask on the surface of the silicon wafer.

[0009] Further, an air curtain is also provided at the connection between the first drying chamber and the water vapor chamber to keep the back surface of the silicon wafer dry.

[0010] Further, the acidic gas chamber includes an upper chamber and a lower chamber arranged longitudinally, and the lower chamber is wider than the upper chamber.

[0011] Further, at least one set of blowers is arranged in the lower chamber and is arranged to circulate the acidic gas from top to bottom.

[0012] Further, at least two alkali washing tanks are provided, and the alkali washing tanks can contain alkali solution or special chemical reagents for removing the mask.

[0013] Further, the first pure water washing tank is arranged to remove excess acid solution; the second pure water washing tank is arranged to remove excess alkali solution or special chemical reagents.

[0014] A method for grooving after printing a mask in a single-sided electroplating process, the steps are as follows:

[0015] Loading: The silicon wafers are sequentially arranged on the conveying rollers, and the conveying rollers are started.

[0016] Water vapor spraying and wetting: The silicon wafer enters the water vapor chamber driven by the conveying rollers. After entering the water vapor chamber, a layer of water droplets will be deposited on the surface of the silicon wafer. Due to the difference in hydrophilicity, more water droplets are deposited in the passivation film area than in the mask area.

[0017] Drying: The silicon wafer enters the first drying chamber driven by the conveying rollers. After the silicon wafer enters the first drying chamber, a small amount of water on the mask will be removed and dried by the water absorbing rollers in the first drying chamber, the water on the back surface of the silicon wafer will be dried, and the water in the passivation film area remains.

[0018] Acid mist corrosion: The silicon wafer enters the acidic gas chamber driven by the conveying rollers. After the silicon wafer enters the acidic gas chamber, the acidic gas in the acidic gas chamber circulates from top to bottom driven by the blowers in the acidic gas chamber. The acidic gas dissolves in the remaining water on the passivation film area to form acid to corrode the passivation film, and the back surface of the silicon wafer and the mask are not corroded.

[0019] Pure water washing: The silicon wafer enters the first pure water washing tank driven by the conveying rollers to remove the excess acid solution on the surface of the silicon wafer.

[0020] Alkali washing: The silicon wafer enters the alkali washing tank driven by the conveying rollers, and the mask is removed by alkali solution or special chemical reagents, and the mask material on the surface of the silicon wafer is washed into the collection box in the alkali washing tank.

[0021] Pure water cleaning: Driven by the conveying rollers, the silicon wafer enters the second pure water cleaning tank to remove the excess alkali solution on the surface of the silicon wafer.

[0022] Drying and blanking: Driven by the conveying rollers, the silicon wafer enters the second drying chamber, and after drying the silicon wafer, it is blanked.

[0023] Due to the adoption of the above technical solutions, the following beneficial effects are achieved:

[0024] The passivation film in the area not covered by the mask is removed by gaseous acid mist. Utilizing the hydrophilicity difference between the mask and the passivation film and the characteristic that HF gas is easily soluble in water, the passivation film in the area not covered by the mask is selectively etched, thus greatly reducing the requirement for acid resistance of the mask material and facilitating the implementation of the subsequent electroplating mask process; the HF gas will dissolve into the part of the silicon wafer where water is present to form HF, and HF corrodes the passivation film to achieve the purpose of grooving. The corrosion rate can be controlled by controlling the dissolution amount of HF, and the amount of acid released can be relatively accurately controlled, reducing the acid consumption; there is no water on the lower surface of the silicon wafer and on the mask, so HF cannot be formed and it is not corroded. Therefore, the problems that the mask is prone to falling off and permeating during cleaning in acid solution are solved, greatly reducing the requirement for acid resistance of the mask material and facilitating the progress of the subsequent electroplating mask process.

[0025] The mask is removed by alkaline chemical reagents, exposing the silicon material itself at the position of the gate line pattern, facilitating the subsequent electroplating operation and promoting the electroplating mask process. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention.

[0027] In the figure:

[0028] 10. Water vapor chamber 20. First drying chamber 30. Acid gas chamber

[0029] 40. First pure water cleaning tank 50. Alkaline cleaning tank 60. Second pure water cleaning tank

[0030] 70. Second drying chamber 80. Conveying rollers

[0031] 90. Water absorption rollers 21. Air curtain Detailed Embodiments

[0032] The present invention will be further described below in conjunction with the embodiments and the drawings:

[0033] In the existing electroplating process, a photosensitive or thermosensitive material that is acid-resistant but alkali-sensitive, i.e., a mask, is generally printed on a silicon wafer. The area of this material is the same as the grid line area to be electroplated, and it is cured under certain temperature or light conditions. Then, the silicon wafer is placed in a specific acid solution to remove the passivation film in the area not covered by the mask material, while the area covered by the mask remains unaffected. Then, through an alkali solution or other specific cleaning solution, the mask layer material is removed, so that the silicon material itself is exposed at the grid line pattern position and electroplating can be carried out, while other areas are covered by the passivation film and cannot be electroplated.

[0034] However, the mask material is likely to fall off when soaked in the acid solution, resulting in the film in the area covered by the mask being corroded by the acid solution as well, failing to achieve the masking effect. To address the problems of the mask being prone to falling off and permeating during cleaning in the acid solution, in an embodiment of the present invention, as Figure 1 shown, an apparatus for grooving after printing a mask in a single-sided electroplating process. This apparatus includes several chambers separated from each other, including: a water vapor chamber 10, a first drying chamber 20, an acidic gas chamber 30, a first pure water cleaning tank 40, an alkali cleaning tank 50, a second pure water cleaning tank 60, and a second drying chamber 70 arranged in sequence. Conveyor rollers 80 are provided in the water vapor chamber 10, the first drying chamber 20, the acidic gas chamber 30, the first pure water cleaning tank 40, the alkali cleaning tank 50, the second pure water cleaning tank 60, and the second drying chamber 70. Several silicon wafers are placed side by side on the conveyor rollers 80 and are transmitted through the above chambers in sequence by the conveyor rollers 80 to complete the reaction and process the silicon wafers in sequence. The passivation film in the area not covered by the mask is removed by gas-phase acid mist, thereby greatly reducing the requirement for the acid resistance of the mask material and facilitating the implementation of the subsequent electroplating mask process.

[0035] As Figure 1 shown, a plurality of water vapor generators and nozzles are provided in the water vapor chamber 10. A large amount of water vapor is generated by the water vapor generators and ejected through the nozzles. The water vapor is sprayed onto the surface of the silicon wafer, including the upper surface and the lower surface of the silicon wafer. The amount of water vapor is adjusted by adjusting the opening degree of the nozzle or increasing the pressure, etc., so that water vapor is deposited on the silicon wafer surface. At the same time, at least one water-absorbing roller 90 cooperating with the conveyor roller 80 is provided at the connection between the water vapor chamber 10 and the first drying chamber 20. In this embodiment, two water-absorbing rollers 90 are provided in the water vapor chamber 10 near the first drying chamber 20, and one water-absorbing roller 90 has been omitted in the figure, which is used to remove the excess moisture on the upper surface of the silicon wafer.

[0036] Specifically, the silicon wafers entering the steam chamber 10 have been pre-treated. First, a passivation film is deposited on the surface of the silicon wafers; then a mask that is acid-resistant but alkali-insensitive is printed on the surface of the silicon wafers. The pattern of the mask is the same as the pattern of the grid lines to be electroplated and is cured under certain temperature or light conditions. Among them, the mask is hydrophobic and the passivation film is hydrophilic, and this property is used for the subsequent acid mist corrosion process.

[0037] As Figure 1 shown in the figure, at least one water-absorbing roller 90 that cooperates with the conveying roller 80 is provided at the connection between the first drying chamber 20 and the steam chamber 10. The silicon wafers are transmitted through the conveying roller 80, and the excess water on the upper surface of the silicon wafers is removed through the water-absorbing roller 90; in this embodiment, two water-absorbing rollers 90 are provided in the first drying chamber 20 close to the steam chamber 10. At the same time, an air curtain 21 is also provided at the connection between the first drying chamber 20 and the steam chamber 10. The air curtain 21 is arranged between the conveying rollers 80. The back surface of the silicon wafer is purged through the air curtain 21 to keep the back surface of the silicon wafer dry and prevent it from wetting the subsequent conveying roller 80, thereby contacting the acid mist to form liquid acid and corroding the lower surface of the silicon wafer. Through the setting of the first drying chamber 20, a small amount of water on the back surface and the mask is dried, while the water at the position of the passivation film is retained.

[0038] As Figure 1 shown in the figure, the acidic gas chamber 30 includes an upper chamber and a lower chamber arranged longitudinally. In this embodiment, the acidic gas is HF gas. The upper chamber of the acidic gas chamber 30 is narrow and the lower chamber is wide, and the lower chamber is wider than the upper chamber; at least one set of fans is provided in the lower chamber, and the HF gas is pumped into the upper chamber through the fans, thereby forming a downward airflow to make the HF gas circulate from top to bottom. After the silicon wafer enters the acidic gas chamber 30, the HF gas will dissolve into the wetted part of the silicon wafer to form HF, and HF corrodes the passivation film to achieve the purpose of grooving. The corrosion rate can be controlled by controlling the dissolution amount of HF, and the concentration of HF can be adjusted according to the reaction rate; there is no water on the lower surface of the silicon wafer and the mask, so HF cannot be formed and thus it is not corroded, thereby solving the problems that the mask is prone to falling off and permeating during cleaning in acid solution, greatly reducing the requirement of the mask material for acid resistance, and being beneficial to the subsequent electroplating mask process.

[0039] As Figure 1 shown in the figure, the first pure water cleaning tank 40 is arranged after the acidic gas chamber 30, and the silicon wafers are cleaned with pure water in the first pure water cleaning tank 40 to remove the excess HF acid solution on the surface of the silicon wafers.

[0040] As Figure 1As shown, there are at least two alkali cleaning tanks 50, and the mask is removed through the alkali cleaning tanks 50. In this embodiment, two alkali cleaning tanks are provided, namely the first alkali cleaning tank 51 and the second alkali cleaning tank 52. The first alkali cleaning tank 51 and the second alkali cleaning tank 52 are arranged in sequence. The alkali cleaning tank 50 in this embodiment is an immersion type cleaning tank. The chemicals in the alkali cleaning tank 50 that can remove the mask are sodium hydroxide or potassium hydroxide, and the concentration is generally 10%-40%, and the reaction temperature is 30-50°C. As an alternative solution, the alkali solution can also be a special cleaning agent for the mask composition, as long as it can remove the mask. In this embodiment, the reaction in the first alkali cleaning tank 51 is intense, and a lot of the mask falls off during the cleaning process, and more reaction products are generated. Therefore, a water knife is arranged at the discharge port at the connection between the first alkali cleaning tank 51 and the second alkali cleaning tank 22 to wash the reaction products generated during the cleaning process, and the mask material on the surface of the silicon wafer is washed into the collection box so that it is not carried into the second alkali cleaning tank 52. The reaction in the second alkali cleaning tank 52 is stable, with few reaction products, and the silicon wafer is cleaned twice.

[0041] As Figure 1 shown, the second pure water cleaning tank 60 is arranged after the alkali cleaning tank 50. The silicon wafer is cleaned with pure water in the second pure water cleaning tank 60 to clean the remaining alkali solution.

[0042] As Figure 1 shown, the second drying chamber 70 contains several groups of fans and air knives. The air knife can be, but is not limited to, a hot air knife. The silicon wafer processed by the alkali cleaning tank 50 is dried through the setting of the hot air knife.

[0043] In addition, the first drying chamber 20 and the second drying chamber 70 of this device are both provided with an exhaust system. The exhaust system is connected to the acid exhaust, and the waste liquid discharge system is connected to the wastewater treatment station. Since the existing technology is relatively perfect, it will not be elaborated here.

[0044] A method for grooving after printing a mask in a single-sided electroplating process, the steps are as follows:

[0045] Loading: The silicon wafers are sequentially arranged on the conveying rollers 80, and the conveying rollers 80 are started.

[0046] Steam spraying and wetting: The silicon wafer enters the steam chamber 10 driven by the conveying rollers 80. After entering the steam chamber 10, a layer of water droplets will be deposited on the surface of the silicon wafer, including the upper surface and the lower surface of the silicon wafer. More water droplets are deposited in the passivation film area than in the mask area.

[0047] Drying: The silicon wafer enters the first drying chamber 20 driven by the conveying rollers 80. After the silicon wafer enters the first drying chamber 20, a small amount of water on the back surface of the silicon wafer and the mask will be removed, and the water in the passivation film area is retained.

[0048] Acid mist corrosion: The silicon wafer enters the acidic gas chamber 30 driven by the transfer roller 80. After the silicon wafer enters the acidic gas chamber 30, the HF gas in the acidic gas chamber 30 circulates from top to bottom driven by the fan in the acidic gas chamber 30. After the silicon wafer enters the acidic gas chamber 30, the HF gas will dissolve into the wetted part of the silicon wafer to form HF, which corrodes the silicon nitride to achieve the purpose of grooving. The corrosion rate can be controlled by controlling the dissolution amount of HF; there is no water on the lower surface of the silicon wafer and the mask, so HF cannot be formed and it is not corroded;

[0049] Pure water cleaning: The silicon wafer enters the first pure water cleaning tank 40 driven by the transfer roller 80 to remove the excess HF on the surface of the silicon wafer;

[0050] Alkaline washing: The silicon wafer enters the alkaline washing tank 50 driven by the transfer roller 80, passes through the first alkaline washing tank 51 and the second alkaline washing tank 52 in sequence, and removes the mask through the alkaline chemical reagent to expose the silicon material itself at the gate line pattern position, facilitating subsequent electroplating operations, and flushing the mask material on the surface of the silicon wafer into the collection box in the alkaline washing tank 50;

[0051] Pure water cleaning: The silicon wafer enters the second pure water cleaning tank 60 driven by the transfer roller 80 to remove the excess alkaline solution on the surface of the silicon wafer;

[0052] Drying and blanking: The silicon wafer enters the second drying chamber 70 driven by the transfer roller 80, and the silicon wafer is dried and then blanked.

[0053] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. An apparatus for grooving after printing a mask in a single-sided electroplating process, characterized in that, Including: A steam chamber, a first drying chamber, an acidic gas chamber, a first pure water cleaning tank, an alkali cleaning tank, a second pure water cleaning tank, and a second drying chamber that are sequentially arranged for processing silicon wafers; Transfer rollers are arranged in the steam chamber, the first drying chamber, the acidic gas chamber, the first pure water cleaning tank, the alkali cleaning tank, the second pure water cleaning tank, and the second drying chamber, and the transfer rollers are arranged to place and transport silicon wafers; A grooving method for a grooving device of a single-sided electroplating process after printing a mask, the steps are: Loading: Sequentially arrange the silicon wafers on the transfer rollers and start the transfer rollers; Steam spraying and wetting: The silicon wafers enter the steam chamber driven by the transfer rollers. After entering the steam chamber, a layer of water droplets will be deposited on the surface of the silicon wafers. Due to the difference in hydrophilicity, more deposition occurs in the passivation film area than in the mask area; Drying: The silicon wafers enter the first drying chamber driven by the transfer rollers. After the silicon wafers enter the first drying chamber, a small amount of water on the mask will be removed and dried by the water-absorbing rollers in the first drying chamber, the water on the back surface of the silicon wafers will be dried, and the water in the passivation film area remains; Acid mist corrosion: The silicon wafers enter the acidic gas chamber driven by the transfer rollers. After the silicon wafers enter the acidic gas chamber, the acidic gas in the acidic gas chamber circulates from top to bottom driven by the fan in the acidic gas chamber. The acidic gas dissolves in the remaining water on the passivation film area to form acid to corrode the passivation film, and the back surface and the mask of the silicon wafers are not corroded; Pure water cleaning: The silicon wafers enter the first pure water cleaning tank driven by the transfer rollers to remove the excess acid solution on the surface of the silicon wafers; Alkali cleaning: The silicon wafers enter the alkali cleaning tank driven by the transfer rollers to remove the mask through alkali solution and wash the mask material on the surface of the silicon wafers into the collection box in the alkali cleaning tank; Pure water cleaning: The silicon wafers enter the second pure water cleaning tank driven by the transfer rollers to remove the excess alkali solution on the surface of the silicon wafers; Drying and unloading: The silicon wafers enter the second drying chamber driven by the transfer rollers, and the silicon wafers are dried and then unloaded.

2. The equipment for grooving after printing a mask in a single-sided electroplating process according to claim 1, characterized in that: Multiple groups of steam generators and injection ports are arranged in the steam chamber, and the injection ports are arranged to inject steam onto the surface of the silicon wafers, and the amount of the steam ejected by the injection ports is adjustable.

3. The device for grooving after printing a mask in a single-sided electroplating process according to claim 1, wherein: At least one water-absorbing roller that cooperates with the transfer rollers is arranged at the connection between the first drying chamber and the steam chamber for removing the excess moisture on the mask on the surface of the silicon wafers.

4. The equipment for grooving after printing a mask in a single-sided electroplating process according to claim 3, characterized in that: An air curtain is also arranged at the connection between the first drying chamber and the steam chamber for keeping the back surface of the silicon wafers dry.

5. The equipment for grooving after printing a mask in a single-sided electroplating process according to claim 1, characterized in that: The acidic gas chamber includes an upper chamber and a lower chamber arranged longitudinally, and the lower chamber is wider than the upper chamber.

6. The equipment for grooving after printing a mask in a single-sided electroplating process according to claim 5, wherein: At least one group of fans is arranged in the lower chamber and is arranged to make the acidic gas circulate from top to bottom.

7. The device for grooving after printing a mask in a single-sided electroplating process according to claim 1, wherein: At least two alkali cleaning tanks are arranged, and the alkali cleaning tanks can contain alkali solution for removing the mask.

8. The equipment for grooving after printing a mask in a single-sided electroplating process according to claim 1, characterized in that: The first pure water cleaning tank is arranged to remove the excess acid solution; The second pure water washing tank is set to remove excess lye.

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