Glass passivation process

Abstract

The invention relates to the technical field of semiconductor device chip manufacturing, in particular to a glass passivation process which comprises the following steps: preparing a glass powder emulsion, terpilenol and glass powder in a weight ratio of 1: 2.2, and uniformly stirring; coating the surface of the wafer with a glass powder emulsion in a blade manner, so that the table-board groove is filled with the glass powder emulsion; baking with a hot plate at 150 DEG C, and wiping off redundant glass powder outside the table top groove; the temperature control program is as follows (the oxygen flow is 10L / min): the initial temperature is 500 DEG C, the temperature is raised to 750 + / -5 DEG C at the speed of 5 DEG C / min, the constant temperature is kept for 15 minutes, the temperature is reduced to 500 DEG C at the speed of 2.5 DEG C / min, the wafer is taken out, and passivation is completed. According to the method, the passivation processing temperature is far higher than the boiling point of terpilenol, and a large flow of oxygen is introduced in the process, so that terpilenol is completely gasified and is purged and removed by carried gas, and no residual is left on the wafer. And the electrical performance of the product is fully ensured.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device chip manufacturing technology, and more specifically to a glass passivation process. Background Technology

[0002] In manufacturing high-voltage semiconductor chips, a common PN junction protection measure is to etch a groove onto the wafer and then passivate it with glass. After the PN junction is etched into a groove, it is exposed. A glass powder of appropriate composition is coated onto its surface, and then heated at a certain high temperature to melt the glass powder, forming a dense protective layer of suitable thickness covering the PN junction surface to achieve passivation. Since glass powder, as a powder, is difficult to adhere in the groove, it must be mixed with a viscous adhesive for easy coating. Traditional adhesives are made from butyl carbitol (solvent) and ethyl cellulose (binder), with the former being the solvent and the latter the binder.

[0003] A mixture of glass powder and binder is coated on the wafer surface. After baking, the solvent evaporates first, and then the wafer enters a passivation furnace in two steps. In the first step, the binder is removed at a lower temperature and oxygen is introduced. In the second step, the glass powder is sintered at a higher temperature to form the wafer.

[0004] Analysis of the process reveals that butyl carbitol and ethyl cellulose, used as binders, require low-temperature diffusion during passivation, which also introduces the issue of volatile organic compounds. Summary of the Invention

[0005] The purpose of this invention is to provide a glass passivation process in which the binder is terpineol, eliminating the need for low-temperature firing and improving production efficiency.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A glass passivation process includes the following steps:

[0008] Step 1: Stir terpineol and glass powder evenly to obtain a glass emulsion with terpineol as a binder;

[0009] Step 2: Apply the glass powder emulsion to the wafer surface using a scraper, ensuring the glass powder emulsion fills the mesa groove.

[0010] Step 3: Bake on a hot plate at 150℃ and wipe away excess glass powder outside the countertop groove;

[0011] Step 4: Place the cleaned silicon wafer on a quartz boat and perform diffusion furnace sintering.

[0012] As a further aspect of the present invention: in step 1, the weight ratio of terpineol to glass powder is 1:2.0-2.4.

[0013] As a further aspect of the present invention: In step 1, the preparation process of the glass emulsion with terpineol as the binder is as follows:

[0014] Pour terpineol into a corundum jar, add glass powder according to the ratio, and grind for 12 hours.

[0015] As a further aspect of the present invention: the glass powder is GP-370.

[0016] As a further aspect of the present invention, the boiling point of terpineol is 218°C.

[0017] As a further aspect of the present invention: in step 3, the baking time of the hot plate at 150°C is 10 minutes.

[0018] As a further aspect of the present invention: in step 4, the oxygen flow rate is 10 L / min.

[0019] As a further aspect of the present invention, the temperature control program is as follows:

[0020] The initial temperature was 500℃, and the temperature was increased to 750±5℃ at a rate of 5℃ / min, and held at the temperature for 15min.

[0021] The temperature was lowered to 500℃ at a rate of 2.5℃ / min, the wafer was removed, and passivation was completed.

[0022] As a further aspect of the present invention: terpineol vaporizes at temperatures above 218°C, and during sintering at 750°C, terpineol is carried out by O2 in the furnace during the process before glass crystallization.

[0023] The beneficial effects of this invention are:

[0024] This invention uses terpineol as a binder. Terpineol can effectively disperse glass powder particles to form a uniform and stable "emulsion". It has sufficient viscosity to support the glass powder particles and prevent them from settling too quickly, while maintaining good fluidity so that it can smoothly fill the fine mesa groove structure on the wafer surface during coating, ensuring no voids or insufficient filling.

[0025] Terpineol exhibits good wettability on both glass powder particles and wafer surfaces (typically silicon or silicon with a metallization layer). This allows the slurry to spread evenly on the wafer surface and effectively wet all corners and sidewalls of the mesa, ensuring that the glass powder is uniformly filled to the required locations.

[0026] The boiling point of terpineol (218℃) is crucial for process design. Baking stage (150℃): At this temperature, terpineol begins to volatilize significantly (although not yet at its boiling point, the vapor pressure increases substantially), causing the slurry to initially solidify and dry, facilitating the removal of excess glass powder outside the countertop groove. If the boiling point is too low (e.g., close to or below 150℃), the slurry may dry too quickly during coating, affecting filling and coating uniformity; if the boiling point is too high, excessive residue after baking at 150℃ will affect the wiping effect or cause defects due to excessive volatilization during the initial sintering stage.

[0027] Initial sintering stage (starting at 500℃): When the wafer enters the 500℃ furnace tube, the temperature is much higher than the boiling point of terpineol (218℃). The passivation processing temperature is also much higher than the boiling point of terpineol, and a large flow of oxygen is introduced during the process. Under the high temperature (500-750℃) environment with a large amount of oxygen (10L / min), the vaporized terpineol will undergo a complete oxidation reaction (combustion) with the oxygen. Its molecular structure (C... 10 H 18 The carbon and hydrogen elements in (O) are ultimately mainly converted into carbon dioxide and water vapor, while the oxygen element becomes part of the product. Terpineol is completely vaporized and purged away by the carrying gas, leaving no residue on the wafer; the electrical performance of the product is fully guaranteed.

[0028] The melting point of terpineol at 18°C ​​means that it is liquid at room temperature and under normal operating conditions (typically >20°C), making it easy to store, handle, mix, and coat. No additional heating is required for melting. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] Example 1

[0031] This invention provides a glass passivation process, which specifically includes the following steps:

[0032] Step 1: Prepare the glass emulsion; mix terpineol and glass powder evenly to obtain a glass emulsion with terpineol as the binder; wherein, the purchased terpineol (C 10 H 18 O, molecular weight 154.25, melting point 18℃, boiling point 218℃, density 0.934 g / cm³ 3 The glass powder is GP-370.

[0033] The weight ratio of terpineol to glass powder is 1:2.0.

[0034] Specifically, the detailed preparation process of the glass emulsion is as follows:

[0035] Pour terpineol into a corundum jar and add glass powder in proportion. Place the corundum jar containing glass powder and binder on the horizontal cylinder shaft of a ball mill and grind for 12 hours at a speed of 160 rpm to obtain a glass emulsion.

[0036] Step 2: Apply the glass powder emulsion to the wafer surface using a scraper, ensuring the glass powder emulsion fills the mesa groove.

[0037] In step 2, the specific process of coating the glass powder emulsion onto the wafer surface is as follows:

[0038] Dip a glass rod into 1-2 drops of glass emulsion and apply it to the silicon wafer placed on the vacuum chuck. Use a blade to scrape along the diagonal of the rectangular chip twice. Rotate the silicon wafer 90° and scrape twice more to fill the groove with glass emulsion.

[0039] Step 3: Bake on a hot plate at 150℃ and wipe away excess glass powder outside the countertop groove;

[0040] In step 3, the specific process of baking and wiping away excess glass powder with a 150℃ hot plate is as follows:

[0041] S31. Place the silicon wafer coated with the glass powder mixture on a heating plate (about 150°C) and dry it for about 10 minutes.

[0042] S32. Place the dried silicon wafer on a vacuum base covered with lint-free paper;

[0043] S33. Use a silicone eraser to wipe away the powder at a 45-degree angle.

[0044] S34. After rotating the vacuum base 90 degrees, repeat S32.

[0045] S35. Repeat S33 until no glass powder is visible to the naked eye on the surface;

[0046] S36. Replace with a new dust-free paper every 2 sheets, and repeat steps S32, S33, and S34 until there is no visible glass powder on the back.

[0047] Step 4: Place the cleaned silicon wafers on a quartz boat and perform diffusion furnace sintering treatment;

[0048] The process parameters for diffusion furnace sintering are as follows: oxygen flow rate 10 L / min, initial temperature 500℃, heating to 745℃ at a rate of 5℃ / min, holding at the temperature for 15 min, and cooling to 500℃ at a rate of 2.5℃ / min.

[0049] Specifically, the detailed process of diffusion furnace sintering is as follows:

[0050] S41. Push the sintering boat into the quartz elephant, put the quartz elephant on the furnace mouth quartz, and connect the automatic push-pull rod and the quartz boat with the quartz hook.

[0051] S42. Set the "In / Out" button to the "IN" position, press the "START" button, and push the boat into the constant temperature zone at a speed of 50mm / min.

[0052] S43. Click the "Start Process" icon on the program display interface to run the program (sintering conditions: initial temperature set at 500℃, constant temperature T2=745℃, constant temperature time: t=15min, heating rate: 5℃ / min, cooling rate: 2.5℃ / min, oxygen flow rate: 10L / min). The "Start Process" icon will display as: process in progress.

[0053] S44. When the program ends, the device will beep and the "Start Process" icon will automatically reset.

[0054] S45. Set the "In / Out" button to the "OUT" position, press the "START" button, and the quartz boat will be pulled back to the furnace opening. After cooling for 5 minutes, remove the quartz elephant and then pull the boat onto the tray.

[0055] S46. After the silicon wafer has cooled for 10 minutes, place the tray and quartz boat on the laminar flow table, and use tweezers to remove the silicon wafer and transfer it to the original wafer box.

[0056] Example 2

[0057] This invention provides a glass passivation process, which specifically includes the following steps:

[0058] Step 1: Prepare the glass emulsion; mix terpineol and glass powder evenly to obtain a glass emulsion with terpineol as the binder; wherein, the purchased terpineol (C 10 H 18 O, molecular weight 154.25, melting point 18℃, boiling point 218℃, density 0.934 g / cm³ 3 The glass powder is GP-370.

[0059] The weight ratio of terpineol to glass powder is 1:2.2.

[0060] Specifically, the detailed preparation process of the glass emulsion is as follows:

[0061] Pour terpineol into a corundum jar and add glass powder in proportion. Place the corundum jar containing glass powder and binder on the horizontal cylinder shaft of a ball mill and grind for 12 hours at a speed of 160 rpm to obtain a glass emulsion.

[0062] Step 2: Apply the glass powder emulsion to the wafer surface using a scraper, ensuring the glass powder emulsion fills the mesa groove.

[0063] In step 2, the specific process of coating the glass powder emulsion onto the wafer surface is as follows:

[0064] Dip a glass rod into 1-2 drops of glass emulsion and apply it to the silicon wafer placed on the vacuum chuck. Use a blade to scrape along the diagonal of the rectangular chip twice. Rotate the silicon wafer 90° and scrape twice more to fill the groove with glass emulsion.

[0065] Step 3: Bake on a hot plate at 150℃ and wipe away excess glass powder outside the countertop groove;

[0066] In step 3, the specific process of baking and wiping away excess glass powder with a 150℃ hot plate is as follows:

[0067] S31. Place the silicon wafer coated with the glass powder mixture on a heating plate (about 150°C) and dry it for about 10 minutes.

[0068] S32. Place the dried silicon wafer on a vacuum base covered with lint-free paper;

[0069] S33. Use a silicone eraser to wipe away the powder at a 45-degree angle.

[0070] S34. After rotating the vacuum base 90 degrees, repeat S32.

[0071] S35. Repeat S33 until no glass powder is visible to the naked eye on the surface;

[0072] S36. Replace the cleanroom paper every 2-3 sheets and repeat steps S32, S33, and S34 until there is no visible glass powder on the back.

[0073] Step 4: Place the cleaned silicon wafers on a quartz boat and perform diffusion furnace sintering treatment;

[0074] The process parameters for diffusion furnace sintering are as follows: oxygen flow rate 10 L / min, initial temperature 500℃, heating to 750℃ at a rate of 5℃ / min, holding at the temperature for 15 min, and cooling to 500℃ at a rate of 2.5℃ / min.

[0075] Specifically, the detailed process of diffusion furnace sintering is as follows:

[0076] S41. Push the sintering boat into the quartz elephant, put the quartz elephant on the furnace mouth quartz, and connect the automatic push-pull rod and the quartz boat with the quartz hook.

[0077] S42. Set the "In / Out" button to the "IN" position, press the "START" button, and push the boat into the constant temperature zone at a speed of 50mm / min.

[0078] S43. Click the "Start Process" icon on the program display interface to run the program (sintering conditions: initial temperature set at 500℃, constant temperature T2=750℃, constant temperature time: t=15min, heating rate: 5℃ / min, cooling rate: 2.5℃ / min, oxygen flow rate: 10L / min). The "Start Process" icon will display as: process in progress.

[0079] S44. When the program ends, the device will beep and the "Start Process" icon will automatically reset.

[0080] S45. Set the "In / Out" button to the "OUT" position, press the "START" button, and the quartz boat will be pulled back to the furnace opening. After cooling for 5 minutes, remove the quartz elephant and then pull the boat onto the tray.

[0081] S46. After the silicon wafer has cooled for 10 minutes, place the tray and quartz boat on the laminar flow table, and use tweezers to remove the silicon wafer and transfer it to the original wafer box.

[0082] Example 3

[0083] This invention provides a glass passivation process, which specifically includes the following steps:

[0084] Step 1: Prepare the glass emulsion; mix terpineol and glass powder evenly to obtain a glass emulsion with terpineol as the binder; wherein, the purchased terpineol (C 10 H 18 O, molecular weight 154.25, melting point 18℃, boiling point 218℃, density 0.934 g / cm³ 3 The glass powder is GP-370.

[0085] The weight ratio of terpineol to glass powder is 1:2.4.

[0086] Specifically, the detailed preparation process of the glass emulsion is as follows:

[0087] Pour terpineol into a corundum jar and add glass powder in proportion. Place the corundum jar containing glass powder and binder on the horizontal cylinder shaft of a ball mill and grind for 12 hours at a speed of 160 rpm to obtain a glass emulsion.

[0088] Step 2: Apply the glass powder emulsion to the wafer surface using a scraper, ensuring the glass powder emulsion fills the mesa groove.

[0089] In step 2, the specific process of coating the glass powder emulsion onto the wafer surface is as follows:

[0090] Dip a glass rod into 1-2 drops of glass emulsion and apply it to the silicon wafer placed on the vacuum chuck. Use a blade to scrape along the diagonal of the rectangular chip twice. Rotate the silicon wafer 90° and scrape twice more to fill the groove with glass emulsion.

[0091] Step 3: Bake on a hot plate at 150℃ and wipe away excess glass powder outside the countertop groove;

[0092] In step 3, the specific process of baking and wiping away excess glass powder with a 150℃ hot plate is as follows:

[0093] S31. Place the silicon wafer coated with the glass powder mixture on a heating plate (about 150°C) and dry it for about 10 minutes.

[0094] S32. Place the dried silicon wafer on a vacuum base covered with lint-free paper;

[0095] S33. Use a silicone eraser to wipe away the powder at a 45-degree angle.

[0096] S34. After rotating the vacuum base 90 degrees, repeat S32.

[0097] S35. Repeat S33 until no glass powder is visible to the naked eye on the surface;

[0098] S36. Replace the cleanroom paper every 2-3 sheets and repeat steps S32, S33, and S34 until there is no visible glass powder on the back.

[0099] Step 4: Place the cleaned silicon wafers on a quartz boat and perform diffusion furnace sintering treatment;

[0100] The process parameters for diffusion furnace sintering are as follows: oxygen flow rate 10 L / min, initial temperature 500℃, heating to 755℃ at a rate of 5℃ / min, holding at the temperature for 15 min, and cooling to 500℃ at a rate of 2.5℃ / min.

[0101] Specifically, the detailed process of diffusion furnace sintering is as follows:

[0102] S41. Push the sintering boat into the quartz elephant, put the quartz elephant on the furnace mouth quartz, and connect the automatic push-pull rod and the quartz boat with the quartz hook.

[0103] S42. Set the "In / Out" button to the "IN" position, press the "START" button, and push the boat into the constant temperature zone at a speed of 50mm / min.

[0104] S43. Click the "Start Process" icon on the program display interface to run the program (sintering conditions: initial temperature set at 500℃, constant temperature T2=755℃, constant temperature time: t=15min, heating rate: 5℃ / min, cooling rate: 2.5℃ / min, oxygen flow rate: 10L / min). The "Start Process" icon will display as: process in progress.

[0105] S44. When the program ends, the device will beep and the "Start Process" icon will automatically reset.

[0106] S45. Set the "In / Out" button to the "OUT" position, press the "START" button, and the quartz boat will be pulled back to the furnace opening. After cooling for 5 minutes, remove the quartz elephant and then pull the boat onto the tray.

[0107] S46. After the silicon wafer has cooled for 10 minutes, place the tray and quartz boat on the laminar flow table, and use tweezers to remove the silicon wafer and transfer it to the original wafer box.

[0108] Comparative Example 1

[0109] The binder in Comparative Example 1 was a mixture of ethyl cellulose and butyl carbitol, with a ratio of 1.25 g to 100 mL.

[0110] The glass passivation process of Comparative Example 1 includes the following steps:

[0111] Prepare adhesive

[0112] Ethyl cellulose and butyl carbitol are mixed in the above proportions to obtain the binder;

[0113] The binder was poured into a corundum jar, and glass powder was added in proportion. The corundum jar containing glass powder and binder was placed on the horizontal cylinder shaft of a ball mill and ground for 12 hours at a speed of 160 rpm to obtain a glass emulsion. The mass ratio of binder to glass powder was 1:2.8.

[0114] The glass powder emulsion is scraped onto the wafer surface to fill the mesa groove.

[0115] Place the silicon wafers on a 130℃ baking pan and bake for at least 2 minutes. Each wafer should not overlap on the hot plate. Then, place them vertically on a quartz boat at certain intervals to prepare for furnace entry. Set the operating program (burning conditions: T1=460℃, t=60min, oxygen flow rate: 10L / min). After the operation is completed, cool for 5 minutes.

[0116] Push the sintering boat into the quartz elephant, put the quartz elephant on the quartz at the furnace mouth, and connect the automatic push-pull rod and the quartz boat with the quartz hook.

[0117] Set the "In / Out" button to the "IN" position, press the "START" button, and the push-pull lever will push the boat into the constant temperature zone at a speed of 50mm / min.

[0118] Click the "Start Process" icon on the program display interface to run the program (sintering conditions: initial temperature set at 500℃, constant temperature T2=750℃, constant temperature time: t=15min, heating rate: 5℃ / min, cooling rate: 2.5℃ / min, oxygen flow rate: 10L / min). The "Start Process" icon will then display as: process in progress.

[0119] When the program ends, the device will beep and the "Start Process" icon will automatically reset.

[0120] Set the "In / Out" button to the "OUT" position, press the "START" button, and the quartz boat will be pulled back to the furnace opening. After cooling for 5 minutes, remove the quartz elephant and then pull the boat onto the tray.

[0121] After the silicon wafer has cooled for 10 minutes, place the tray and quartz boat on the laminar flow table, and use tweezers to remove the silicon wafer and transfer it to the original wafer cassette.

[0122] Performance testing

[0123] The passivated wafers of Examples 1-3 and Comparative Example 1 were subjected to yield performance tests (46 yield tests were conducted for each example and comparative example). The test results are as follows:

[0124] Yield (%) Example 1 98% Example 2 98% Example 3 98% Comparative Example 1 94%

[0125] As can be seen from the table above, the glass passivation process using terpineol as a binder can improve the product qualification rate to a certain extent.

[0126] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A glass passivation process, characterized in that, Includes the following steps: Step 1: Stir terpineol and glass powder evenly to obtain a glass emulsion with terpineol as a binder; Step 2: Apply the glass powder emulsion to the wafer surface using a scraper, ensuring the glass powder emulsion fills the mesa groove. Step 3: Bake on a hot plate at 150℃ and wipe away excess glass powder outside the countertop groove; Step 4: Place the cleaned silicon wafer on a quartz boat and perform diffusion furnace sintering.

2. The glass passivation process according to claim 1, characterized in that, In step 1, the weight ratio of terpineol to glass powder is 1:2.0-2.

4.

3. The glass passivation process according to claim 1, characterized in that, In step 1, the preparation process of the glass emulsion with terpineol as a binder is as follows: Pour terpineol into a corundum jar, add glass powder according to the ratio, and grind for 12 hours.

4. The glass passivation process according to claim 1, characterized in that, The glass powder is GP-370.

5. The glass passivation process according to claim 1, characterized in that, Terpineol has a boiling point of 218°C.

6. The glass passivation process according to claim 1, characterized in that, In step 3, the baking time on the hot plate at 150°C is 10 minutes.

7. The glass passivation process according to claim 1, characterized in that, In step 4, the oxygen flow rate is 10 L / min.

8. The glass passivation process according to claim 5, characterized in that, The temperature control program is as follows: The initial temperature was 500℃, and the temperature was increased to 750±5℃ at a rate of 5℃ / min, and held at the temperature for 15min. The temperature was lowered to 500℃ at a rate of 2.5℃ / min, the wafer was removed, and passivation was completed.

9. A glass passivation process according to claim 8, characterized in that, Terpineol vaporizes at temperatures above 218°C. During sintering at 750°C, terpineol is carried out by O2 in the furnace during the process before glass crystallization.