Method for fabricating gate oxide layer of power MOSFET device

Abstract

This invention discloses a method for preparing the gate oxide layer of a power MOSFET device, relating to the field of semiconductor device processing technology. The preparation steps include: Step 1, providing a MOSFET device; Step 2, pre-treating the surface of the MOSFET device for 25-35 minutes; Step 3, immersing the MOSFET device in an immersion tank filled with an acidic solution for 15-25 minutes; Step 4, removing the MOSFET device from the immersion tank and fixing it onto a placement device. This invention, by pre-treating the surface of the MOSFET device during preparation, followed by cleaning with an acidic solution, and finally annealing it in a furnace filled with inert gas, completes the surface annealing treatment of the power MOSFET device. This enhances the overall strength of the MOSFET device's gate oxide layer and comprehensively cleans adhering impurities from the MOSFET device surface, improving the internal purity of the MOSFET device's gate oxide layer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device processing technology, specifically to a method for preparing the gate oxide layer of a power MOSFET device. Background Technology

[0002] In order to ensure the quality and reliability of the integrated circuit chip after installation, a gate oxide layer needs to be deposited on the outer surface of the MOSFET device during manufacturing.

[0003] Since MOSFET devices may be contaminated by particles, metals, organic molecules, and electrostatic discharge (ESD) during the entire manufacturing process, defects may occur in the gate oxide layer. These tiny defects can reduce the overall strength of the MOSFET device, leading to threshold drift, increased leakage current, or even irreversible device damage such as low-voltage breakdown, thus affecting the quality and reliability of the entire integrated circuit chip. To address these issues, a method for preparing the gate oxide layer of a power MOSFET device is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating the gate oxide layer of a power MOSFET device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing the gate oxide layer of a power MOSFET device, comprising the following preparation steps:

[0006] Step 1: Provide MOSFET devices:

[0007] Step 2: Pre-treat the surface of the MOSFET device for 25-35 minutes.

[0008] Step 3: Place the MOSFET device into an immersion tank filled with an acidic solution and immerse it for 15 to 25 minutes.

[0009] Step 4: Remove the MOSFET device from the immersion tank, then install it onto the placement device and fix it in place. Finally, place the device together with the MOSFET device into a heating furnace filled with inert gas for baking. The temperature of the heating furnace is 260℃~330℃, the baking time is 25min~30min, and the filling time with inert gas is 10min~15min.

[0010] Step 5: Remove the MOSFET device from the heating furnace and place it in a nitrogen chamber to stand.

[0011] Step 6: When the temperature outside the MOSFET device stabilizes at 110-130°C, remove the outside of the MOSFET device from the nitrogen cabinet.

[0012] Furthermore, the pretreatment in step two includes polishing, grinding, and sandblasting steps, with the total time ratio of polishing, grinding, and sandblasting being 3:1:2.

[0013] Furthermore, the acidic solution in step three is either a hydrochloric acid solution with a mass fraction of 18% or a dilute nitric acid solution with a mass fraction of 16%.

[0014] Furthermore, a second cleaning of the MOSFET device is required between steps three and four. The second cleaning requires pure water, and the device should be placed in a ventilated environment for 15 to 30 minutes after cleaning.

[0015] Furthermore, in step four, the inert gas is one of argon, helium, or neon, and hydrogen is added to the heating furnace after the inert gas is filled in step four.

[0016] Furthermore, the installation device in step four includes an assembly component, one end of which is slidably connected to a clamping mechanism, and the other end of which is fixed to a drive mechanism. The output end of the drive mechanism drives the clamping mechanism to reciprocate on the top of the assembly component.

[0017] Furthermore, the assembly assembly includes an assembly table, with lifting blocks fixedly connected to both ends of the top of the assembly table, and open slots fixedly connected to both sides of the top of the two lifting blocks.

[0018] The clamping mechanism includes a placement block, with a stop cylinder slidably connected to both ends of the placement block. The stop cylinder is adapted to the interior of the opening groove, and the placement block is slidably connected inside the opening groove through the stop cylinder.

[0019] Furthermore, a clamping arm is slidably connected to one end of the top of the placement block, and a through hole is opened at the other end of the top of the placement block. A fixing arm is fixedly connected inside the through hole. Two connecting elongated holes are opened on both sides of the top of the placement block, and both connecting elongated holes are located between the clamping arm and the fixing arm.

[0020] Furthermore, a drive motor is fixedly connected to one end of the bottom of the placement block, and a threaded shaft is fixedly connected to the output end of the drive motor. One end of the threaded shaft is hinged to one end of the bottom of the fixing arm. A hinge frame is screwed to the outside of the threaded shaft, and the two sides of the top of the hinge frame pass through the through-hole and are fixed to the two sides of the bottom of the clamping arm.

[0021] Furthermore, a connector is fixedly connected to one side of the outer side of the placement block, the driving mechanism includes a stabilizing frame, the bottom of the stabilizing frame is fixed to the top of the assembly table, a sliding groove is provided on one side of the top of the stabilizing frame, a sliding block is hinged inside the sliding groove, a vertical hinge groove is fixedly connected to one side of the sliding block, and one end of the connector is hinged to the inside of the hinge groove.

[0022] The stabilizer has a through hole inside the sliding groove. Two drive gears are rotatably connected to the other two ends of the stabilizer. A chain is installed between the two drive gears. An extension platform is fixedly connected to the bottom of one end of the stabilizer. An input motor is fixed to the top of the extension platform. The output end of the input motor is fixed to the outside of one of the drive gears.

[0023] A connecting block is fixedly connected to one side of the sliding block, and one end of the connecting block passes through the elongated hole and is fixed to the outside of the chain.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The method for preparing the gate oxide layer of this power MOSFET device involves pretreating the surface of the MOSFET device during its preparation, cleaning it with an acid solution after pretreatment, and finally placing it in a heating furnace filled with inert gas to complete the annealing treatment of the power MOSFET device surface. This method not only enhances the overall strength of the gate oxide layer of the MOSFET device but also thoroughly cleans the adhering impurities on the surface of the MOSFET device, thereby improving the internal purity of the gate oxide layer of the MOSFET device.

[0026] The method for preparing the gate oxide layer of this power MOSFET device indirectly improves the efficiency of the annealing process by placing the power MOSFET device into a heating furnace using a placement device. This allows the outer surface of the MOSFET device to come into contact with the inert gas filled in the heating furnace under the action of the placement device. Attached Figure Description

[0027] Figure 1 This is an isometric view of the placement device in this invention;

[0028] Figure 2 This is an oblique side view of the placement device in this invention;

[0029] Figure 3 This is a structural composition diagram of the assembly components in this invention;

[0030] Figure 4 This is an isometric view of the clamping mechanism in this invention;

[0031] Figure 5 This is an oblique axonometric view of the clamping mechanism in this invention;

[0032] Figure 6 This is an isometric view of the drive mechanism in this invention;

[0033] Figure 7 This is an oblique axonometric view of the driving mechanism in this invention.

[0034] In the diagram: 1. Assembly component; 101. Assembly table; 102. Lifting block; 103. Opening slot; 2. Clamping mechanism; 201. Placement block; 202. Connecting elongated hole; 203. Supporting cylinder; 204. Clamping arm; 205. Connector; 206. Fixing arm; 207. Drive motor; 208. Hinge frame; 209. Threaded shaft; 3. Drive mechanism; 301. Stabilizer; 302. Drive gear; 303. Through elongated hole; 304. Connecting block; 305. Chain; 306. Extension table; 307. Input motor; 308. Sliding groove; 309. Sliding block; 310. Hinge slot. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0036] It should be noted that in the description of this invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0039] In order to ensure the quality and reliability of the integrated circuit chip after installation, a gate oxide layer needs to be deposited on the outer surface of the MOSFET device during manufacturing.

[0040] Because MOSFET devices may be contaminated by particles, metals, organic molecules, and electrostatic discharge (ESD) during the entire manufacturing process, defects may occur in the gate oxide layer. These tiny defects can reduce the overall strength of the MOSFET device, leading to threshold drift, increased leakage current, and even irreversible device damage such as low-voltage breakdown, thus affecting the quality and reliability of the entire integrated circuit chip. To address these issues, a new solution is proposed, and the fabrication steps are as follows:

[0041] Step 1: Provide MOSFET devices:

[0042] Step 2: Pre-treat the surface of the MOSFET device for 25-35 minutes.

[0043] Step 3: Place the MOSFET device into an immersion tank filled with an acidic solution and immerse it for 15 to 25 minutes.

[0044] Step 4: Remove the MOSFET device from the immersion tank, then install it onto the placement device and fix it in place. Finally, place the device together with the MOSFET device into a heating furnace filled with inert gas for baking. The temperature of the heating furnace is 260℃~330℃, the baking time is 25min~30min, and the filling time with inert gas is 10min~15min.

[0045] Step 5: Remove the MOSFET device from the heating furnace and place it in a nitrogen chamber to stand.

[0046] Step 6: When the temperature outside the MOSFET device stabilizes at 110-130°C, remove the outside of the MOSFET device from the nitrogen cabinet.

[0047] It should be noted that the pretreatment in step two of this application includes polishing, grinding and sandblasting steps, wherein the total time ratio of polishing, grinding and sandblasting is 3:1:2.

[0048] It should be noted that, in this application, the acidic solution in step three is either a hydrochloric acid solution with a mass fraction of 18% or a dilute nitric acid solution with a mass fraction of 16%.

[0049] It should be further explained that a second cleaning of the MOSFET device is required between steps three and four in this application. The second cleaning requires pure water, and after cleaning, it needs to be placed in a ventilated environment for 15 to 30 minutes. It should be emphasized that this setting in this application allows the surface dirt residue left on the semiconductor mold after cleaning with sulfuric acid solution to form an oxide layer when the MOSFET device is placed in the heating furnace for baking and oxygen is filled into it. By polishing the oxide layer, the surface of the MOSFET device becomes smoother.

[0050] Furthermore, it should be noted that in step four of this application, the inert gas is one of argon, helium, or neon. After filling with inert gas, hydrogen is also filled into the heating furnace in step four. It should be added that this application pre-treats the surface of the power MOSFET device during the fabrication of the power MOSFET device, cleans it with an acid solution after pre-treatment, and finally places it in a heating furnace and fills the heating furnace with inert gas to complete the annealing treatment of the surface of the power MOSFET device. This not only enhances the overall strength of the gate oxide layer of the MOSFET device, but also thoroughly cleans the attached impurities on the surface of the MOSFET device, thereby improving the internal purity of the gate oxide layer of the MOSFET device.

[0051] In addition, it should be noted that the mounting device in step four can increase the contact between the outer surface of the MOSFET device and the inert gas filled into the heating furnace, thereby indirectly improving the efficiency of the annealing process.

[0052] Among them, reference Figures 1-7 As can be seen, the installation device in this application includes an assembly component 1, a clamping mechanism 2 is slidably connected to one end of the top of the assembly component 1, and a drive mechanism 3 is fixed to the other end of the top of the assembly component 1. The output end of the drive mechanism 3 drives the clamping mechanism 2 to reciprocate on the top of the assembly component 1.

[0053] refer to Figure 3 As can be seen, in this application, assembly component 1 includes an assembly table 101, with lifting blocks 102 fixedly connected to both ends of the top of the assembly table 101, and opening slots 103 fixedly connected to both sides of the top of the two lifting blocks 102. It should be noted that the structure of the opening slots 103 in this application is as follows: Figure 3 As shown.

[0054] refer to Figure 4 and Figure 5As can be seen, in this application, the clamping mechanism 2 includes a placement block 201. Two ends of the placement block 201 are slidably connected to abutting cylinders 203. The abutting cylinders 203 and the interior of the opening groove 103 are adapted to each other. The placement block 201 is slidably connected inside the opening groove 103 via the abutting cylinders 203. It should be added that in this application, a clamping arm 204 is slidably connected to one end of the top of the placement block 201, and a through hole is opened at the other end of the top of the placement block 201. A fixing arm 206 is fixedly connected inside the through hole. The two sides of the top of the placement block 201... Two connecting elongated holes 202 are provided, and both connecting elongated holes 202 are located between the clamping arm 204 and the fixing arm 206. In addition, it should be noted that in this application, a drive motor 207 is fixedly connected to one end of the bottom of the placement block 201, and a threaded shaft 209 is fixedly connected to the output end of the drive motor 207. One end of the threaded shaft 209 is hinged to one end of the bottom of the fixing arm 206. A hinge frame 208 is screwed to the outside of the threaded shaft 209. The two sides of the top of the hinge frame 208 pass through the connecting elongated holes 202 and are fixed to the two sides of the bottom of the clamping arm 204.

[0055] It should be emphasized that in actual use, the mechanical device in the clamping mechanism 2 can be of various types. For example, in this application, the drive motor 207 in the clamping mechanism 2 can be a high-power geared motor. Since the high-power geared motor has the characteristic of strong overload capacity, the output power of this device can be greater than that of other motors in actual use. Therefore, when clamping MOSFET devices, its clamping speed is much faster than that of other motors.

[0056] Furthermore, it should be noted that in this application, a connector 205 is fixedly connected to one side of the outer surface of the block 201, wherein reference is made to... Figure 6 and Figure 7 As can be seen, the drive mechanism 3 includes a stabilizer 301, the bottom of which is fixed to the top of the assembly table 101. A sliding groove 308 is provided on one side of the top of the stabilizer 301, and a sliding block 309 is hinged inside the sliding groove 308. A vertical hinge groove 310 is fixedly connected to one side of the sliding block 309. One end of the connector 205 is hinged to the inside of the hinge groove 310. It should be noted that in this application, the structure of the connector 205 and... Figure 4 The structures are the same.

[0057] It should also be noted that in this application, the stabilizer 301 has a through-hole 303 inside the sliding groove 308. The two ends of the other side of the stabilizer 301 are respectively rotatably connected to drive gears 302. A chain 305 is installed between the two drive gears 302. An extension platform 306 is fixedly connected to the bottom of one end of the stabilizer 301. An input motor 307 is fixed to the top of the extension platform 306. The output end of the input motor 307 is fixed to the outside of one of the drive gears 302. In addition, it should be noted that in this application, a connecting block 304 is fixedly connected to one side of the sliding block 309. One end of the connecting block 304 passes through the through-hole 303 and is fixed to the outside of the chain 305.

[0058] In actual use, the device operates via an external controller, which drives the drive motor 207. When operating, the drive motor 207 rotates the threaded shaft 209, causing the threaded shaft 209 to move the clamping arm 204 via its externally screwed hinge bracket 208. At this point, the MOSFET device is placed on the placement block 201, with one end of the MOSFET device contacting the outer end of the clamping arm 204. When the other end of the MOSFET device contacts one end of the fixing arm 206, the MOSFET is clamped. Simultaneously, the external controller activates the input motor 307. When the input motor 307 operates, one drive gear 302 rotates, driving the other drive gear 302 to rotate via a chain 305. As the chain 305 moves, it causes the connecting block 304 to move as well. 04 During movement, the sliding block 309 and the hinge groove 310 will move together. Since the interior of the hinge groove 310 is hinged to the connector 205, the hinge groove 310 will pull the placement block 201 to move together through the connector 205 when it moves. When the abutting cylinder 203 at one end of the placement block 201 contacts the interior of the opening groove 103, the connector 205 moves up to the top of the hinge groove 310. The placement block 201 flips with the abutting cylinder 203 as the fulcrum. At this time, the MOSFET device on the placement block 201 is fully in contact with the inert gas. When the placement block 201 flips, the input motor 307 rotates in the opposite direction through programming. At this time, the connector 205 moves from the top of the hinge groove 310 to the midpoint of its interior, and the placement block 201 returns to the flat state from the flipped state.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating the gate oxide layer of a power MOSFET device, characterized in that: The preparation steps are as follows: Step 1: Provide MOSFET devices: Step 2: Pre-treat the surface of the MOSFET device for 25-35 minutes. Step 3: Place the MOSFET device into an immersion tank filled with an acidic solution and immerse it for 15 to 25 minutes. Step 4: Remove the MOSFET device from the immersion tank, then install it onto the placement device and fix it in place. Finally, place the device together with the MOSFET device into a heating furnace filled with inert gas for baking. The temperature of the heating furnace is 260℃~330℃, the baking time is 25min~30min, and the filling time with inert gas is 10min~15min. Step 5: Remove the MOSFET device from the heating furnace and place it in a nitrogen chamber to stand. Step 6: When the temperature outside the MOSFET device stabilizes at 110-130°C, remove the outside of the MOSFET device from the nitrogen cabinet. The pretreatment in step two includes polishing, grinding, and sandblasting, with the total time ratio of polishing, grinding, and sandblasting being 3:1:

2. The acidic solution in step three is either a hydrochloric acid solution with a mass fraction of 18% or a dilute nitric acid solution with a mass fraction of 16%. A second cleaning of the MOSFET device is required between steps three and four. The second cleaning should be done with pure water, and the device should be placed in a ventilated environment for 15 to 30 minutes after cleaning. In step four, the inert gas is one of argon, helium, or neon. After filling with the inert gas, hydrogen is also filled into the heating furnace in step four.

2. The method for fabricating the gate oxide layer of a power MOSFET device according to claim 1, characterized in that: The installation device in step four includes an assembly component (1), one end of which is slidably connected to a clamping mechanism (2), and the other end of which is fixed to a drive mechanism (3). The output end of the drive mechanism (3) drives the clamping mechanism (2) to reciprocate on the top of the assembly component (1).

3. The method for fabricating the gate oxide layer of a power MOSFET device according to claim 2, characterized in that: The assembly component (1) includes an assembly table (101), with lifting blocks (102) fixedly connected to both ends of the top of the assembly table (101), and opening slots (103) fixedly connected to both sides of the top of the two lifting blocks (102). The clamping mechanism (2) includes a placement block (201), and two ends of the placement block (201) are slidably connected to a stop cylinder (203). The stop cylinder (203) and the interior of the opening groove (103) are adapted to each other. The placement block (201) is slidably connected to the interior of the opening groove (103) through the stop cylinder (203).

4. The method for fabricating the gate oxide layer of a power MOSFET device according to claim 3, characterized in that: One end of the top of the placement block (201) is slidably connected to a clamping arm (204), and the other end of the top of the placement block (201) is provided with a through hole. A fixing arm (206) is fixedly connected inside the through hole. Two connecting elongated holes (202) are respectively provided on both sides of the top of the placement block (201). Both connecting elongated holes (202) are located between the clamping arm (204) and the fixing arm (206).

5. The method for fabricating the gate oxide layer of a power MOSFET device according to claim 4, characterized in that: One end of the bottom of the placement block (201) is fixedly connected to a drive motor (207), and the output end of the drive motor (207) is fixedly connected to a threaded shaft (209). One end of the threaded shaft (209) is hinged to one end of the bottom of the fixed arm (206). A hinge frame (208) is screwed to the outside of the threaded shaft (209). The two sides of the top of the hinge frame (208) pass through the connecting elongated hole (202) and are fixed to the two sides of the bottom of the clamping arm (204).

6. The method for fabricating the gate oxide layer of a power MOSFET device according to claim 3, characterized in that: A connector (205) is fixedly connected to one side of the outer side of the placement block (201). The driving mechanism (3) includes a stabilizer (301). The bottom of the stabilizer (301) is fixed to the top of the assembly table (101). A sliding groove (308) is provided on one side of the top of the stabilizer (301). A sliding block (309) is hinged inside the sliding groove (308). A vertical hinge groove (310) is fixedly connected to one side of the sliding block (309). One end of the connector (205) is hinged to the inside of the hinge groove (310). The stabilizer (301) has a through hole (303) inside the sliding groove (308). The two ends of the other side of the stabilizer (301) are respectively rotatably connected to drive gears (302). A chain (305) is installed between the two drive gears (302). An extension platform (306) is fixedly connected to the bottom of one end of the stabilizer (301). An input motor (307) is fixed to the top of the extension platform (306). The output end of the input motor (307) is fixed to the outside of one of the drive gears (302). A connecting block (304) is fixedly connected to one side of the sliding block (309), and one end of the connecting block (304) passes through the through hole (303) and is fixed to the outside of the chain (305).

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