Electronic grade hexamethyldisilazane metal detection pretreatment auxiliary device

Abstract

The application discloses an electronic-grade hexamethyldisilazane metal-detecting pretreatment auxiliary device, which comprises an electric heating plate, a digestion tank arranged on the electric heating plate and an acrylic dustproof box covering the electric heating plate and the digestion tank, and the opposite side walls of the acrylic dustproof box are respectively connected with an air inlet pipe and a second air outlet pipe, the top of the acrylic dustproof box is connected with a first air outlet pipe, the first air outlet pipe is connected with a suction pump, and the input end of the first air outlet pipe is located at the top opening of the digestion tank. The experimental device can precisely perform efficient pretreatment on hexamethyldisilazane and avoid external pollution, the recovery rate of the hexamethyldisilazane pretreated by the device is stably 80%-110%, which is much higher than that of the national standard (GB / T 27404-2008), and the parallelism of each parallel sample is very good.

Description

Technical Field

[0001] This utility model relates to the technical field of hexamethyldisilazane pretreatment equipment, and in particular to an auxiliary device for pretreatment of electronic-grade hexamethyldisilazane for metal determination. Background Technology

[0002] Electronic-grade hexamethyldisilazane, a key surface treatment agent in semiconductor manufacturing, derives its core value from the precise control of the surface energy levels of silicon wafers. Before photolithography, the agent is deposited onto the silicon substrate surface via vapor deposition to form a monolayer, which then undergoes a dehydroxylation reaction with the hydroxyl groups on the SiO2 surface: 2Si-OH + (CH3)3Si-NH-Si(CH3)3 → 2Si-O-Si(CH3)3 + NH3↑. The resulting methylsiloxane hydrophobic layer (contact angle >90°) significantly reduces the substrate surface energy (from ~50 mJ / m² to ~20 mJ / m²), improving the wettability of photoresists by more than 30%, especially enhancing the adhesion of 248nm and EUV photoresists.

[0003] In advanced processes below 14nm, the homogeneous film deposition technology of hexamethyldisilazane is crucial. It requires a dual-temperature vacuum chamber (main chamber 80-120℃, auxiliary chamber 150-180℃) to achieve monolayer thickness control (0.7-1.2nm), combined with in-situ FTIR monitoring of the Si-O-Si vibration peak (~1250cm⁻¹) to ensure complete reaction. In 3D-NAND manufacturing, hexamethyldisilazane-modified trench surfaces with an aspect ratio >60:1 can reduce the risk of developer penetration, achieving defect density control of <0.01 / cm². Furthermore, its application as an ALD precursor in low-k dielectric layer deposition is gradually expanding. Low-temperature growth of nanoscale dielectric films can be achieved by controlling the Si-N bond dissociation temperature (~400℃). Process optimization requires balancing ammonia byproduct removal efficiency with thermal budget; currently, advanced cluster equipment has achieved residual control of <3ppm.

[0004] For ICP-MS detection equipment, organic samples cannot be directly injected. Therefore, to ensure the accuracy of metal testing for electronic-grade hexamethyldisilazane, sample pretreatment is necessary. Pretreatment methods include digestion and evaporation-resolution. Here, we designed an auxiliary device for the evaporation-resolution method. This device largely avoids contamination from airborne metal impurities and the problem of low spiked recovery, and the spiked recovery rate is far superior to the national standard. Summary of the Invention

[0005] The purpose of this invention is to provide an auxiliary device for metal pretreatment in hexamethyldisilazane assays, addressing the problems of sample contamination by airborne gold impurities and low spike recovery rates caused by excessively high temperatures and slow evaporation. This device is characterized by ease of construction, low cost, minimal environmental pollution, and excellent performance, effectively reducing expenses and time costs while saving human resources.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: an auxiliary device for pretreatment of electronic-grade hexamethyldisilazane for metal determination, including an electric heating plate, a digestion tank arranged on the electric heating plate, and an acrylic dustproof box covering the electric heating plate and the digestion tank. The opposite side walls of the acrylic dustproof box are respectively connected to an air inlet pipe and a second exhaust pipe. The top of the acrylic dustproof box is connected to a first exhaust pipe, and a suction pump is connected to the first exhaust pipe. The input end of the first exhaust pipe is located at the top opening of the digestion tank.

[0007] Preferably, a nitrogen purification tank is connected to the air inlet pipe, the nitrogen purification tank contains an adsorbent material, and a first gas flow meter and a second gas flow meter are respectively connected to the air inlet pipe and the first exhaust pipe.

[0008] Preferably, the inlet pipe is cut off in the middle, and the two ends are respectively connected to the gas supply pipe and the gas return pipe at the top of the nitrogen storage tank. The upstream end of the inlet pipe is connected to the gas supply pipe, and the downstream end of the inlet pipe is connected to the gas return pipe. The bottom end of the gas supply pipe is located at the bottom of the nitrogen purification tank, and the bottom end of the gas return pipe is located at the top of the nitrogen purification tank.

[0009] Preferably, a metal support plate is fixedly connected to the electric heating plate, and the metal support plate has a slot for accommodating the digestion vessel, and the inner wall of the slot is in contact with the outer wall of the digestion vessel.

[0010] Preferably, a fixed pipe is fixedly connected to the top of the acrylic dustproof box, the top end of the fixed pipe is connected to the first exhaust pipe, a telescopic pipe is vertically slidably connected to the bottom of the fixed pipe, a diverter pipe is connected to the bottom end of the telescopic pipe, and the bottom end of the diverter pipe is located at the top of the digestion tank.

[0011] Preferably, an electric telescopic rod is fixedly connected to the fixed pipe, the output end of the electric telescopic rod is fixedly connected to the telescopic pipe, and the bottom end of the diversion pipe is kept above the material inside the digestion tank by the electric telescopic rod.

[0012] Preferably, the output end of the electric telescopic rod is fixedly connected to a connecting block, and a sleeve block is fixedly connected to the side wall of the connecting block, and the sleeve block is fixedly fitted onto the telescopic tube.

[0013] Preferably, the bottom outer wall of the diverter is provided with an annular protrusion, and the top surface of the annular protrusion is provided with an annular receiving groove.

[0014] This invention provides an auxiliary device for the pretreatment of electronic-grade hexamethyldisilazane for metal determination, which has the following beneficial effects.

[0015] 1. The nitrogen gas entering the chamber has been adsorbed and purified, and will not cause internal pollution; the acrylic chamber is a sealed small-capacity type, which can quickly replace the gas inside, avoiding the contamination of the sample by the original gas inside.

[0016] 2. The adjustable PFA rigid tube can be inserted into different depths inside the PFA digestion vessel with the opening open, allowing sample vapor to be quickly drawn away without contacting the drug. The end of the PFA rigid tube is designed to prevent liquid dripping, thus preventing vapor from condensing on the outer tube wall and dripping, and avoiding drug contamination.

[0017] 3. The entire experimental system is transparent and visible, allowing clear observation of the dynamic process within the system and real-time control of the experimental status. The entire device has sensitive temperature and gas control, and can accurately control the parameters. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0019] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.

[0020] In the diagram: 1. Inlet pipe; 2. Nitrogen purification tank; 3. First gas flow meter; 4. Acrylic dustproof box; 5. First exhaust pipe; 6. Second gas flow meter; 7. Digestion tank; 8. Metal support plate; 9. Electric heating plate; 10. Second exhaust pipe; 11. Fixed pipe; 12. Electric telescopic rod; 13. Connecting block; 14. Telescopic pipe; 15. Diverter pipe; 16. Air pump. Detailed Implementation

[0021] like Figure 1 As shown, this utility model provides an auxiliary device for the pretreatment of electronic-grade hexamethyldisilazane for metal determination, including an electric heating plate 9, a digestion tank 7 arranged on the electric heating plate 9, and an acrylic dustproof box 4 covering the electric heating plate 9 and the digestion tank 7. The opposite side walls of the acrylic dustproof box 4 are respectively connected to an air inlet pipe 1 and a second exhaust pipe 10. The top of the acrylic dustproof box 4 is connected to a first exhaust pipe 5, and a vacuum pump 16 is connected to the first exhaust pipe 5. The input end of the first exhaust pipe 5 is located at the top opening of the digestion tank 7.

[0022] When setting up the auxiliary device, first set up the entire device in a fume hood, place the electric heating plate 9 in the center of the acrylic dustproof box 4, and supply nitrogen gas through the air inlet pipe 1. The nitrogen gas enters the acrylic dustproof box 4 and replaces the gas inside the acrylic dustproof box 4. The electric heating plate 9 heats the digestion tank 7, and the temperature is set to 85℃. The electric heating plate 9 heats eight digestion tanks 7. The air pump 16 is turned on and the flow rate of the air pump 16 is set to 0.1ml / s. The internal condition of the digestion tank 7 is observed through the acrylic dustproof box 4. The heating continues until the medicine bottles inside the digestion tank 7 have evaporated completely.

[0023] During the initial gas replacement of the acrylic dust chamber 4, the flow rate of the inlet pipe 1 is relatively large, about 5-15 L / min. After the sample is placed in the acrylic dust chamber 4 and heating is started, the nitrogen flow rate is controlled at 0.5-2.5 L / min to fully ensure the safety of the sample. The digestion vessel 7 is a PFA digestion vessel.

[0024] The acrylic dustproof box 4 is a transparent box measuring 100cm*40cm*40cm, with an anti-corrosion coating on its inner surface; the upper surface of the electric heating plate 9 is made of ceramic material, and the heating rate can be adjusted, with a temperature range of 20℃ to 300℃.

[0025] like Figure 1 As shown. A nitrogen purification tank 2 is connected to the inlet pipe 1. The nitrogen purification tank 2 contains adsorbent material. A first gas flow meter 3 and a second gas flow meter 6 are connected to the inlet pipe 1 and the first exhaust pipe 5, respectively. The nitrogen purification tank 2 is made of quartz and has a two-hole opening for installing the gas supply pipe and return pipe. Its interior is filled with adsorbent material, specifically nano-silica balls and degreased cotton, with a diameter of 0.5-1.0 mm. The bottom two-thirds of the inner surface of the nitrogen purification tank 2 is filled with nano-silica balls, and the top one-third is filled with degreased cotton.

[0026] The second gas flow meter 6 is connected to the vacuum pump 16, which uses frequency conversion for airflow regulation. The flow rate can be precisely adjusted based on the reading from the second gas flow meter 6. The exhaust gas extracted by the vacuum pump 16 is treated by an exhaust gas treatment device. The second gas flow meter 6 is highly accurate and sensitive, and is required to monitor gas flow rates between 0.1 and 0.2 ml / s.

[0027] A second exhaust pipe 10 is connected to the rear end of the acrylic dustproof box 4. The second exhaust pipe 10 is used to ensure that the inside of the acrylic dustproof box 4 is in a slightly positive pressure state, and to transport the exhaust gas to the exhaust gas treatment equipment to prevent organic gases from spreading into the environment.

[0028] like Figure 1As shown. The inlet pipe 1 is cut off in the middle, with the two ends connecting to the gas supply pipe and return pipe at the top of the nitrogen storage tank 2, respectively. The upstream end of the inlet pipe 1 connects to the gas supply pipe, and the downstream end connects to the return pipe. The bottom end of the gas supply pipe is located at the bottom of the nitrogen purification tank 2, and the bottom end of the return pipe is located at the top of the nitrogen purification tank 2. The gas supply pipe delivers nitrogen to the bottom of the nitrogen purification tank 2. The gas flows through the adsorption material inside the nitrogen purification tank 2, where the nitrogen is fully adsorbed, thus treating the nitrogen and reducing its moisture and metal content.

[0029] like Figure 1 As shown. A metal support plate 8 is fixedly connected to the electric heating plate 9. The metal support plate 8 has a slot to accommodate the digestion vessel 7, and the inner wall of the slot is in contact with the outer wall of the digestion vessel 7. Eight slots are formed on the top of the metal support plate 8 to accommodate the digestion vessel 7. By positioning the digestion vessel 7 through the slots, the accurate correspondence between the diversion pipe 15 and the digestion vessel 17 can be ensured.

[0030] like Figure 1 As shown. A fixed pipe 11 is fixedly connected to the top of the acrylic dustproof box 4. The top end of the fixed pipe 11 is connected to the first exhaust pipe 5. A telescopic pipe 14 is vertically slidably connected to the bottom of the fixed pipe 11. A diverter pipe 15 is connected to the bottom end of the telescopic pipe 14. The bottom end of the diverter pipe 15 is located at the top of the digestion vessel 7. The fixed pipe 11 is made of PFA rigid pipe. The top end is connected to the top of the acrylic dustproof box 4. A small amount of sealant is applied to the interface between the fixed pipe 11 and the top wall of the acrylic dustproof box 4.

[0031] like Figure 1 As shown. An electric telescopic rod 12 is fixedly connected to the fixed tube 11. The output end of the electric telescopic rod 12 is fixedly connected to the telescopic tube 14, and the electric telescopic rod 12 maintains the bottom end of the diversion tube 15 above the material inside the digestion vessel 7. Eight branch pipes are provided at the bottom end of the diversion tube 15, and the eight branch pipes correspond to the top ends of the eight digestion vessels 7 respectively. The electric telescopic rod 12 adjusts the height of the diversion tube 15 through the telescopic tube 14, adjusting the depth of the diversion tube 15 inside the digestion vessel 7, so that the sample vapor can be quickly drawn away without contacting the medicine bottle; the branch pipes are made of PFA tubing.

[0032] like Figure 1As shown. A connecting block 13 is fixedly connected to the output end of the electric telescopic rod 12. A sleeve block is fixedly connected to the side wall of the connecting block 13, and the sleeve block is fixedly fitted onto the telescopic tube 14. The top of the connecting block 13 is welded to the movable end of the electric telescopic rod 12. Sleeve blocks are connected to the sides of both ends of the connecting block 13, and the telescopic tube 14 is fixedly connected through the sleeve blocks. The outer side wall of the telescopic tube 14 fits against the inner side wall of the fixed tube 11, and the electric telescopic rod 12 can drive the telescopic tube 14 to move stably.

[0033] As a preferred embodiment of this utility model, an annular protrusion is provided on the outer wall of the bottom end of the diversion pipe 15, and an annular receiving groove is formed on the top surface of the annular protrusion. The annular receiving groove on the outer side of the diversion pipe 15 prevents liquid dripping. When vapor condenses on the outer wall of the diversion pipe 15 and drips, the droplets enter the receiving groove, thus avoiding contamination of the medicine bottle.

[0034] The method of using this device is as follows: After setting up the device in the fume hood, place the electric heating plate 9 and the metal heating plate 8 in the center of the acrylic dustproof box 4. Fill the nitrogen purification tank 2 with an appropriate amount of adsorbent material, then adjust the nitrogen flow rate to 10L / min and purge for one hour, then turn off the nitrogen. Place eight open digestion tanks 7, each containing 10ml of hexamethyldisilazane, into the holes of the metal heating plate 8. Adjust the nitrogen flow rate to 1L / min, turn on the electric heating plate 9, set the temperature to 85℃, lower the distributor pipe 15 until the bottom end of the distributor pipe 15 is 1cm above the liquid surface in the digestion tank 7, set the flow rate of the vacuum pump 16 to 0.1ml / s, and turn on the vacuum pump. Observe the readings of the first gas flow meter 3 and the second gas flow meter 6 to stabilize at the gas flow rate set value until the medicine bottles inside the digestion tank 7 have evaporated completely.

[0035] This invention is designed based on the properties of the pharmaceuticals used in the system. Under normal conditions, hexamethyldisilazane and PFA containers exhibit strong adhesion, making it difficult for their vapors to evaporate outside the bottle. This can only be addressed by increasing the temperature and heating time, which inevitably reduces the spike recovery rate and leads to poor parallelism in test results. Furthermore, direct evaporation in an open environment is susceptible to contamination by trace metals in the air. The device invented in this patent cleverly solves these problems. It not only rapidly evaporates samples at low temperatures but also avoids contamination by trace metals in the air. The tail gas is directly discharged into the tail gas treatment system, preventing environmental pollution. Evaporation within a sealed chamber reduces the risk of contamination. Inserting a negative-pressure PFA tube that does not contact the pharmaceuticals into the open digestion bottle quickly removes sample vapors, reducing the vapor pressure above the liquid surface and allowing for continuous and rapid evaporation of the pharmaceuticals. This ensures rapid evaporation even at low temperatures. Multiple experiments have shown that 80-90℃ is the most suitable temperature range.

Claims

1. An auxiliary device for metal pretreatment in electronic-grade hexamethyldisilazane, characterized in that: It includes an electric heating plate (9), a digestion vessel (7) arranged on the electric heating plate (9), and an acrylic dustproof box (4) covering the electric heating plate (9) and the digestion vessel (7). The opposite side walls of the acrylic dustproof box (4) are respectively connected to an air inlet pipe (1) and a second exhaust pipe (10). The top of the acrylic dustproof box (4) is connected to a first exhaust pipe (5), and a vacuum pump (16) is connected to the first exhaust pipe (5). The input end of the first exhaust pipe (5) is located at the top opening of the digestion vessel (7).

2. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 1, characterized in that: The air inlet pipe (1) is connected to a nitrogen purification tank (2), which contains an adsorbent material. The air inlet pipe (1) and the first exhaust pipe (5) are respectively connected to a first gas flow meter (3) and a second gas flow meter (6).

3. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 2, characterized in that: The inlet pipe (1) is cut off in the middle, and the two ends are respectively connected to the gas supply pipe and the gas return pipe at the top of the nitrogen purification tank (2). The upstream end of the inlet pipe (1) is connected to the gas supply pipe, and the downstream end of the inlet pipe (1) is connected to the gas return pipe. The bottom end of the gas supply pipe is located at the bottom of the nitrogen purification tank (2), and the bottom end of the gas return pipe is located at the top of the nitrogen purification tank (2).

4. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 1, characterized in that: A metal support plate (8) is fixedly connected to the electric heating plate (9). The metal support plate (8) has a slot for accommodating the digestion vessel (7), and the inner wall of the slot is in contact with the outer wall of the digestion vessel (7).

5. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 1, characterized in that: The top of the acrylic dustproof box (4) is fixedly connected to a fixed pipe (11). The top of the fixed pipe (11) is connected to the first exhaust pipe (5). The bottom of the fixed pipe (11) is vertically slidably connected to a telescopic pipe (14). The bottom end of the telescopic pipe (14) is connected to a diversion pipe (15). The bottom end of the diversion pipe (15) is located at the top of the digestion tank (7).

6. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 5, characterized in that: An electric telescopic rod (12) is fixedly connected to the fixed pipe (11). The output end of the electric telescopic rod (12) is fixedly connected to the telescopic pipe (14), and the bottom end of the diversion pipe (15) is kept above the material inside the digestion tank (7) by the electric telescopic rod (12).

7. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 6, characterized in that: The output end of the electric telescopic rod (12) is fixedly connected to a connecting block (13), and a sleeve block is fixedly connected to the side wall of the connecting block (13). The sleeve block is fixedly fitted onto the telescopic tube (14).

8. The electronic-grade hexamethyldisilazane metal pretreatment auxiliary device as described in claim 5, characterized in that: The bottom outer wall of the diversion pipe (15) is provided with an annular protrusion, and the top surface of the annular protrusion is provided with an annular receiving groove.

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