Gas distributor for ALD (Atomic Layer Deposition) equipment and ventilation method for growing thin film on wafer through ALD

Abstract

The invention belongs to the technical field of atomic layer deposition equipment, and particularly relates to a gas distributor for ALD equipment and a ventilation method for growing a thin film on a wafer through ALD. The gas distributor for the ALD equipment is arranged in the reaction chamber and is positioned above the base station; the gas distributor comprises a gas inlet and a conical spiral conveying channel, the gas inlet is communicated with a gas source, one end of the conveying channel is provided with an inlet section communicated with the gas inlet, and the other end of the conveying channel is provided with a closed section. The radius of the circumference where the closed section is located is smaller than that of the circumference where the inlet section is located, the horizontal height of the closed section is larger than that of the inlet section, the conveying channel is provided with an air outlet hole in the length direction, and the air outlet hole faces the base table. The ALD film growth process is carried out on an 8-inch wafer by adopting the gas distributor provided by the invention, and the obtained film has high thickness uniformity and good optical uniformity.

Description

Technical Field

[0001] This invention belongs to the field of atomic layer deposition equipment technology, specifically relating to a gas distributor for ALD equipment and a gas supply method for growing thin films on wafers via ALD. Background Technology

[0002] Atomic layer deposition (ALD) technology plays an increasingly important role in semiconductor manufacturing. With the continuous advancement of microelectronic processes, ALD technology, with its high precision, high uniformity, and excellent control over composition, has become a key technology for manufacturing high-performance, high-reliability micro and nano devices. Currently, the process of depositing thin films on 4-inch and 6-inch wafers using ALD technology has been matured. However, when the wafer size is further expanded to 8 inches (diameter up to 200 mm) or even 12 inches (diameter up to 300 mm), the traditional ALD equipment's radiation heating or resistance heating system is difficult to achieve temperature control within ±1℃ across the entire wafer. At this time, the temperature in the edge area may be 2~5℃ lower than that in the center due to the longer heat conduction path. On the one hand, this will lead to differences in film growth rate (up to 10%~15%), resulting in uneven thickness and poor optical performance uniformity. On the other hand, this temperature gradient will cause uneven stress distribution in the film, especially the stress concentration in the edge area, which will lead to wafer warping (warping degree >20μm), affecting the subsequent photolithography alignment accuracy. Secondly, the large difference in thermal expansion coefficients between the film and the silicon substrate will cause stress accumulation during cooling, leading to film cracking or peeling. The existence of these problems greatly reduces the production yield and efficiency of the 8-inch wafer thin film deposition process. However, in order to adapt to market demands, further improve production efficiency and reduce production costs, the key is how to achieve uniform and repeatable thin film deposition on 8-inch wafers using ALD equipment. Summary of the Invention

[0003] After extensive and in-depth research, the inventors of this invention discovered that while improving the heating system of the ALD (Alternating Current Deposition) equipment is a key element in achieving uniform and repeatable thin film deposition on wafers, the high degree of technical integration and difficulty in disassembly of the heating system, coupled with the risk of process window shifts and the need for re-optimization of process parameters if changes are made, make improving the gas distributor of the ALD equipment to compensate for the non-uniformity caused by temperature differences on 8-inch wafers a more economical and feasible approach. Current patent literature discloses the use of spiral gas distributors in ALD equipment to provide uniform gas flow. However, while such planar spiral gas distributors can provide uniform output airflow, their effectiveness in addressing the growth rate differences caused by edge heat loss on 8-inch wafers is limited. Consequently, the thin films deposited on 8-inch wafers still suffer from uneven thickness and poor optical performance uniformity.

[0004] One of the objectives of this invention is to provide a new gas distributor to solve the problems of uneven thickness and poor optical performance uniformity in existing ALD equipment when depositing thin films on 8-inch wafers.

[0005] The ALD device includes a reaction chamber and a base for placing wafers is provided inside the reaction chamber.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The gas distributor for the ALD device is disposed in the reaction chamber and above the base. The gas distributor includes an inlet and a conveying channel with a conical spiral shape. The inlet is connected to a gas source. One end of the conveying channel is provided with an inlet section connected to the inlet, and the other end of the conveying channel is provided with a closed section. The radius of the circumference of the closed section is smaller than the radius of the circumference of the inlet section. The horizontal height of the closed section is higher than the horizontal height of the inlet section. The conveying channel is provided with an outlet along its length, and the direction of the outlet is opposite to the base.

[0007] In some embodiments of the present invention, the cross-section of the conveying channel is circular.

[0008] In some embodiments of the present invention, the number of turns of the conveying channel is 3 to 5.

[0009] In some embodiments of the present invention, the spacing between the conveying channels of adjacent cycles is 2 to 8 cm.

[0010] In some embodiments of the present invention, the pitch of the conveying channel is 1~5cm.

[0011] In some embodiments of the present invention, the spacing between the air outlets is 1 to 5 cm.

[0012] In some embodiments of the present invention, the ratio between the diameter of the air outlet and the diameter of the conveying channel is 1:(0.03~0.5).

[0013] In some embodiments of the present invention, the diameter of the air outlet is 1-5 mm, and the diameter of the conveying channel is 10-30 mm.

[0014] In some embodiments of the present invention, the gas source includes a carrier gas tank, a reaction gas tank, and a metal source precursor tank, and the number of each of the carrier gas tank, the reaction gas tank, and the metal source precursor tank is 1 to 3.

[0015] In some embodiments of the present invention, the gas in the carrier gas tank is argon and / or nitrogen.

[0016] In some embodiments of the present invention, the gas in the reaction tank is ammonia or ozone.

[0017] In some embodiments of the present invention, the metal source precursor container contains at least one of aluminum metal precursor, titanium metal precursor, molybdenum metal precursor, and nickel metal precursor.

[0018] In some embodiments of the present invention, the air inlet is connected to a carrier gas tank, a reaction gas tank, and a metal source precursor tank, respectively; a first gas valve is provided on the connecting pipeline between the air inlet and the carrier gas tank to regulate the flow rate of the carrier gas entering the delivery channel; a second gas valve is provided on the connecting pipeline between the air inlet and the reaction gas tank to regulate the flow rate of the reaction gas entering the delivery channel; and a third gas valve is provided on the connecting pipeline between the air inlet and the metal source precursor tank to regulate the flow rate of the metal source precursor entering the delivery channel.

[0019] A second objective of this invention is to provide a ventilation method for growing thin films on wafers via ALD. This ventilation method is implemented using the gas distributor described above for ALD equipment and includes: placing the wafer on a substrate, heating it to a set reaction temperature, first introducing reaction gas A into the reaction chamber to cause an adsorption reaction with the wafer surface, then introducing inert gas I for purging, followed by introducing reaction gas B into the reaction chamber to cause a chemical reaction on the wafer surface, and then introducing inert gas II for purging, thus completing one growth cycle for thin film formation.

[0020] In some embodiments of the present invention, the diameter of the wafer is 8 inches.

[0021] In some embodiments of the present invention, when the reaction gas A is ammonia or ozone, the reaction gas B contains a metal source precursor; or, when the reaction gas A contains a metal source precursor, the reaction gas B is ammonia or ozone.

[0022] In some embodiments of the present invention, both reaction gas A and reaction gas B are introduced into the reaction chamber in the form of pulses.

[0023] In some embodiments of the present invention, the inert gas I and inert gas II are each independently argon and / or nitrogen.

[0024] In some embodiments of the present invention, the metal source precursor is selected from at least one of aluminum metal precursor, titanium metal precursor, molybdenum metal precursor, and nickel metal precursor.

[0025] In some embodiments of the present invention, the flow rate of ammonia or ozone is 100-1000 sccm and the time is 20-40 s.

[0026] In some embodiments of the present invention, when the reaction gas contains a metal source precursor, the reaction gas is introduced in a pulsed manner using inert gas III as the carrier gas, with an inert gas flow rate of 10~100 sccm and a duration of 0.5~1.0 s.

[0027] Compared with the prior art, the present invention has at least the following advantages and beneficial effects: Gas enters the transport channel through the inlet located at the outermost ring of the conical spiral and at the lowest horizontal height, and exits through the outlet on the transport channel into the reaction chamber, reaching the wafer on the substrate. As the gas flows in the transport channel, the radius of the circumference along the transport channel gradually decreases and the horizontal height gradually increases, enabling the discharged gas to achieve uniform growth of thin films on the 8-inch wafer with high thickness uniformity, good overall optical response uniformity of the thin film, and high repeatability. The reasons for this are speculated to be as follows: First, the spiral motion of the gas along the channel ensures the uniformity of the gas in the circumferential direction (angular direction). In addition, the upward-convex conical structure design can balance the pressure drop and velocity distribution of the gas during the outward flow process, so that the gas discharged through the vent reaches the wafer surface almost vertically, which helps to reduce turbulence and dead zones in the cavity. Second, this upward-convex conical spiral structure makes the time and flux of the gas to reach the wafer surface vary radially, so that the reaction rate at the center and edge of the wafer remains consistent. In summary, this specific upward-convex conical spiral gas distributor structure can optimize the gas flow field distribution, thereby compensating for the difference in film growth rate caused by temperature differences, reducing the difference in film thickness at the center and edge of the wafer, and improving the uniformity and repeatability of the grown film. Attached Figure Description

[0028] Various objects, features, and advantages of the invention will become more apparent from the following detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings. The drawings are merely illustrative of the invention and are not necessarily drawn to scale. In the drawings, the same reference numerals always denote the same or similar parts.

[0029] Figure 1 This is a schematic diagram of the structure of a gas distributor provided in an embodiment of the present invention.

[0030] Figure 2 This is a top view of the structure of a gas distributor provided in an embodiment of the present invention.

[0031] Figure 3 This is a bottom view of the structure of a gas distributor provided in an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram of the connection between a gas distributor and a gas source according to an embodiment of the present invention.

[0033] Figure 5 The graph shows the test results of the aluminum nitride thin film prepared according to Example 1 of the present invention regarding the refractive index n.

[0034] Figure 6 The graph shows the test results of the aluminum nitride thin film prepared using Comparative Example 1 of this invention regarding the refractive index n.

[0035] Reference numerals: 1. Conveying channel; 11. Inlet section; 12. Closed section; 13. Gas outlet; 2. Gas inlet; 21. Carrier gas tank; 211. First carrier gas tank; 212. Second carrier gas tank; 22. Reaction gas tank; 23. Metal source precursor tank; 241. First gas valve; 242. Fourth gas valve; 25. Second gas valve; 26. Third gas valve; 3. Reaction chamber; 4. Base. Detailed Implementation

[0036] Although the invention can be readily embodied in various forms, only some specific embodiments are shown in the accompanying drawings and will be described in detail in this specification. It is understood that this specification should be regarded as an exemplary illustration of the principles of the invention and is not intended to limit the invention to what is described herein.

[0037] Therefore, a feature pointed out in this specification is used to illustrate one feature of one embodiment of the invention, and does not imply that every embodiment of the invention must have the described feature. Furthermore, it should be noted that this specification describes many features. While certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0038] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various elements of the invention are relative rather than absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the descriptions of the positions of these elements change, these directional indications also change accordingly.

[0039] Please see Figures 1 to 3In one embodiment of the present invention, a gas distributor for an ALD device is disposed within a reaction chamber 3 and located above a base 4. The gas distributor includes an inlet 2 and a conveying channel 1 having a conical spiral shape. The inlet 2 is connected to a gas source. One end of the conveying channel 1 is provided with an inlet section 11 connected to the inlet 2, and the other end of the conveying channel 1 is provided with a closed section 12. The radius of the circumference of the closed section 12 is smaller than the radius of the circumference of the inlet section 11, and the horizontal height of the closed section 12 is higher than the horizontal height of the inlet section 11. The conveying channel 1 is provided with an outlet 13 along its length, and the direction of the outlet 13 is opposite to that of the base 4.

[0040] In a specific embodiment, the cross-section of the conveying channel 1 can be circular, or it can be elliptical, square, or other shapes. It should be noted that the cross-sectional shape of the conveying channel 1 needs to ensure that there are no dead zones when the gas flows in the conveying channel 1, and it is preferable to have a circular cross-section.

[0041] In a specific embodiment, the number of revolutions in conveyor channel 1 can be 3, 4, 5, or any value in between. Please refer to... Figure 2 and Figure 3 At this time, the number of rotations of conveyor channel 1 is 3.

[0042] In a specific embodiment, the spacing between adjacent turns of the conveying channel 1 can be 2~8cm, such as 2cm, 3cm, 4cm, 5cm, 6cm, 7cm, 8cm, or any value between them. The pitch of the conveying channel 1 can be 1~5cm, such as 1cm, 2cm, 3cm, 4cm, 5cm, or any value between them. The term "pitch" refers to the distance traveled in the axial direction when a conical helix rotates once around the axis of the cone.

[0043] In specific embodiments, the spacing between the air outlets 13 can be 1 to 5 cm, such as 1 cm, 2 cm, 3 cm, 4 cm, 5 cm or any value between them.

[0044] In a specific embodiment, the ratio between the diameter of the air outlet 13 and the diameter of the conveying channel 1 can be 1:(0.03~0.5), such as 1:0.03, 1:0.05, 1:0.08, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5 or any ratio between them.

[0045] In a further embodiment, the diameter of the air outlet 13 can be 1~5mm, such as 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm, 5mm or any value between them. The diameter of the conveying channel 1 can be 10~30mm, such as 10mm, 15mm, 20mm, 25mm, 30mm or any value between them.

[0046] In a specific embodiment, the gas source includes a carrier gas tank 21, a reaction gas tank 22, and a metal source precursor tank 23. The number of each of the carrier gas tank 21, reaction gas tank 22, and metal source precursor tank 23 can be independently 1 to 3, such as 1, 2, or 3, and the specific number can be selected according to the actual process. Please refer to [link / reference]. Figure 4 There are two gas carrier tanks 21, including a first gas carrier tank 211 and a second gas carrier tank 212.

[0047] In a further embodiment, the gas in carrier gas tank 21 may be argon and / or nitrogen. The gas in reaction gas tank 22 may be ammonia or ozone. Metal source precursor tank 23 may contain at least one of aluminum metal precursor, titanium metal precursor, molybdenum metal precursor, and nickel metal precursor.

[0048] In a specific embodiment, the air inlet 2 is connected to the carrier gas tank 21, the reaction gas tank 22, and the metal source precursor tank 23, respectively. Please refer to [link / reference]. Figure 4 The carrier gas tank 21 includes a first carrier gas tank 211 and a second carrier gas tank 212. A first gas valve 241 is installed on the connecting pipeline between the inlet 2 and the first carrier gas tank 211 to regulate the flow rate of the first carrier gas into the delivery channel 1. A fourth gas valve 242 is installed on the connecting pipeline between the inlet 2 and the second carrier gas tank 212 to regulate the flow rate of the second carrier gas into the delivery channel 1. A second gas valve 25 is installed on the connecting pipeline between the inlet 2 and the reaction gas tank 22 to regulate the flow rate of the reaction gas into the delivery channel 1. A third gas valve 26 is installed on the connecting pipeline between the inlet 2 and the metal source precursor tank 23 to regulate the flow rate of the metal source precursor into the delivery channel 1. It should be noted that the gas valves installed on the connecting pipelines between the inlet 2 and the carrier gas tank 21, the reaction gas tank 22, and the metal source precursor tank 23 are not only for regulating the flow rate but also for preventing gas backflow.

[0049] This invention also provides a venting method for growing thin films on wafers via ALD, applicable to gas distributors with the above-described structure. Specifically, the method includes: placing the wafer on a substrate, heating it to a set reaction temperature, first introducing a reaction gas into the reaction chamber to undergo an adsorption reaction with the wafer surface, then introducing inert gas I for purging, followed by introducing a precursor into the reaction chamber to undergo a chemical reaction on the wafer surface, and then introducing inert gas II for purging, thus completing one growth cycle of thin film formation.

[0050] In a specific embodiment, the diameter of the wafer is preferably 8 inches.

[0051] In a specific embodiment, when the reaction gas A is ammonia or ozone, the reaction gas B contains a metal source precursor; or, when the reaction gas A contains a metal source precursor, the reaction gas B is ammonia or ozone.

[0052] In a specific embodiment, the inert gas I and inert gas II may each be argon and / or nitrogen, respectively.

[0053] In a specific embodiment, the metal source precursor may be selected from at least one of aluminum metal precursor, titanium metal precursor, molybdenum metal precursor, and nickel metal precursor.

[0054] In a specific embodiment, both reaction gas A and reaction gas B are preferably introduced into the reaction chamber in a pulsed manner. When the introduced reaction gas is ammonia or ozone, the flow rate of the ammonia or ozone can be 100~1000 sccm, such as 100 sccm, 200 sccm, 300 sccm, 400 sccm, 500 sccm, 800 sccm, 1000 sccm or any value between them, and the time can be 20~40 s, such as 20 s, 25 s, 30 s, 35 s, 40 s or any value between them.

[0055] In a specific embodiment, when the introduced reaction gas contains a metal source precursor, the reaction gas is introduced in a pulsed manner using inert gas III as the carrier gas. The flow rate of inert gas III can be 10~100 sccm, such as 10 sccm, 20 sccm, 50 sccm, 80 sccm, 100 sccm, or any value between them, and the duration can be 0.5~1.0 s, such as 0.5 s, 0.6 s, 0.7 s, 0.8 s, 0.9 s, 1.0 s, or any value between them. The inert gas III can be argon and / or nitrogen.

[0056] The present invention will be described in detail below through specific embodiments. These embodiments are intended to explain the invention and should not be construed as limiting it. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0057] Example 1 This embodiment illustrates the structure of a gas distributor and a ventilation method for growing aluminum nitride thin films on an 8-inch wafer using an ALD device equipped with the gas distributor, as detailed below: (1) Structure of the gas distributor: such as Figures 1 to 3As shown, a gas distributor is located inside the reaction chamber 3 and above the base 4. The gas distributor includes an inlet 2 and a conical spiral conveying channel 1. One end of the conveying channel 1 has an inlet section 11 communicating with the inlet 2, and the other end has a closed section 12. The radius of the circumference of the closed section 12 is smaller than the radius of the circumference of the inlet section 11, and the horizontal height of the closed section 12 is 3 cm higher than the horizontal height of the inlet section 11. The cross-section of the conveying channel 1 is circular, with 3 turns. The spacing between adjacent turns of the conveying channel 1 is 3 cm, the pitch of the conveying channel is 1 cm, and the diameter of the conveying channel is 10 mm. Gas outlets 13 are provided along the length of the conveying channel 1, and the direction of the gas outlets 13 is opposite to the base 4. The spacing between adjacent gas outlets 13 is 1.5 cm, the number of gas outlets 13 is 75, and the diameter of the gas outlets 13 is 1 mm. The inlet 2 is connected to the carrier gas tank 21, the reaction gas tank 22, and the precursor tank 23, respectively. A first gas valve 241 is installed on the connecting pipeline between inlet 2 and the first carrier gas tank 211 to regulate the flow rate of the first carrier gas (argon) into the delivery channel 1. A fourth gas valve 242 is installed on the connecting pipeline between inlet 2 and the second carrier gas tank 212 to regulate the flow rate of the second carrier gas (nitrogen) into the delivery channel 1. A second gas valve 25 is installed on the connecting pipeline between inlet 2 and the reaction gas tank 22 to regulate the flow rate of the reaction gas (ammonia) into the delivery channel 1. A third gas valve 26 is installed on the connecting pipeline between inlet 2 and the precursor tank 23 to regulate the flow rate of the precursor (trimethylaluminum) into the delivery channel 1.

[0058] (2) Gas supply method for aluminum nitride thin film growth on an 8-inch wafer: Place the 8-inch wafer on the substrate 4 and start the heating program to bring the wafer to the reaction temperature of 250°C; at this time, first open the third gas valve 26 and introduce trimethylaluminum into the reaction chamber 3 through the gas distributor. Trimethylaluminum is introduced in a pulsed manner using nitrogen as the carrier gas. Trimethylaluminum undergoes an adsorption reaction with the wafer surface. The flow rate of trimethylaluminum is 50 mL / min and the time is 0.5 s; after closing the second gas valve 26, open the first gas valve 241 and introduce argon gas into the reaction chamber 3 through the gas distributor for purging. The flow rate of argon gas is 300 mL / min and the time is 0.5 s. 36s; After closing the first gas valve 241, the second gas valve 25 is introduced into the reaction chamber 3 in a pulsed manner through the gas distributor. Ammonia reacts chemically with the previously adsorbed trimethylaluminum on the wafer surface. The ammonia flow rate is 500 mL / min and the time is 30s. After closing the third gas valve 26, the fourth gas valve 242 is opened, and nitrogen is introduced into the reaction chamber 3 through the gas distributor for purging. The nitrogen flow rate is 300 mL / min and the time is 5s. This completes one growth cycle of thin film formation. After performing 500 growth cycles according to the above four steps of the gas transmission method, the deposition of aluminum nitride thin film on the 8-inch wafer is completed.

[0059] Example 2 This embodiment illustrates the structure of a gas distributor and a ventilation method for growing titanium nitride thin films on an 8-inch wafer using an ALD device equipped with the gas distributor, as detailed below: (1) Structure of the gas distributor: It is the same as the structure of (1) in Example 1, except that the precursor tank 23 contains titanium tetrachloride precursor.

[0060] (2) Ventilation method for growing titanium nitride thin film on 8-inch wafer: The method in Example 1 (2) is the same as in Example 1 (2), except that the heating program is started to bring the wafer to the reaction temperature of 400°C. All other conditions are the same as in Example 1 (2). After 500 growth cycles, the deposition of titanium nitride thin film on 8-inch wafer is completed.

[0061] Comparative Example 1 This comparative example illustrates a ventilation method for growing aluminum nitride thin films on an 8-inch wafer using an ALD device, as detailed below: (1) No gas distributor is installed in the reaction chamber 3 of the ALD equipment. The carrier gas, reaction gas and precursor are directly introduced into the reaction chamber 3.

[0062] (2) Ventilation method for aluminum nitride thin film growth on 8-inch wafers: Place the 8-inch wafer on the substrate 4 and start the heating program to bring the wafer to the reaction temperature of 250°C; directly introduce trimethylaluminum into the reaction chamber 3, using nitrogen as the carrier gas in a pulsed manner. Trimethylaluminum undergoes an adsorption reaction with the wafer surface. The flow rate of trimethylaluminum is 50 mL / min, and the time is 0.5 s; then purge the reaction chamber 3 with argon gas in a pulsed manner. The flow rate of argon gas is 30 mL / min. The flow rate is 0 mL / min for 36 s; then ammonia gas is introduced into reaction chamber 3 to react chemically with the trimethylaluminum adsorbed on the wafer surface. The ammonia gas flow rate is 500 mL / min for 30 s; nitrogen gas is then introduced into reaction chamber 3 for purging. The nitrogen gas flow rate is 300 mL / min for 5 s. This completes one growth cycle of film formation. After 500 growth cycles following the above four steps of the gas introduction method, the deposition of aluminum nitride film on the 8-inch wafer is completed.

[0063] Comparative Example 2 This comparative example illustrates the structure of a reference gas distributor and the ventilation method for growing aluminum nitride thin films on an 8-inch wafer using an ALD device equipped with the gas distributor, as detailed below: (1) Structure of the reference gas distributor: It is basically the same as the structure in Example 1 (1), except that the horizontal height of the closed section 12' is the same as the horizontal height of the inlet section 11', that is, the conveying channel 1' of the reference gas distributor has a planar spiral structure and the spacing between adjacent conveying channels 1' is 2.5cm.

[0064] (2) Ventilation method for growing aluminum nitride thin film on 8-inch wafer: After 500 growth cycles according to the method in Example 1 (2), the deposition of aluminum nitride thin film on 8-inch wafer is completed.

[0065] Test case The films prepared in the above examples and comparative examples were subjected to uniformity tests of thickness d and refractive index n using the following methods. The results are shown in Table 1.

[0066] (1) Uniformity test of refractive index n: 29 measurement points were selected on the thin film surface using a spectroscopic ellipsometry (e.g., Figure 5 and Figure 6 As shown in the figure, the refractive index values ​​at each point were measured at a wavelength of 550 nm. The average refractive index n and standard deviation σ of the 29 measurement points were calculated. n The refractive index uniformity coefficient is defined as: uniformity coefficient y n (%)=(1-σ n / n)*100. The test results for Example 1 are as follows: Figure 5 As shown.

[0067] (2) Thickness uniformity test: Using a step profiler or ellipsometry, measurement points corresponding to the refractive index test were selected at the same location on the film surface, and the thickness value at each point was measured. The average thickness d and standard deviation σ of the 29 measurement points were calculated. d The thickness uniformity coefficient is defined as: uniformity coefficient y d (%)=(1-σ d / d)*100.

[0068] All tests were conducted at room temperature (25±2℃) and relative humidity ≤40% to ensure the comparability of the results.

[0069] Table 1

[0070] As shown in Table 1, compared with the comparative example, when using the gas distributor provided in this embodiment of the invention for ALD thin film deposition, the uniformity coefficient of refractive index and thickness of the thin film obtained on the 8-inch wafer is higher and the coefficient of variation is lower, indicating that the thickness and optical response of the thin film are generally uniform.

[0071] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A gas distributor for an ALD (Alternating Current Discharge) device, the ALD device comprising a reaction chamber and a stage for placing a wafer disposed within the reaction chamber, characterized in that, The gas distributor is disposed in the reaction chamber and above the base. The gas distributor includes an inlet and a conical spiral conveying channel. The inlet is connected to a gas source. One end of the conveying channel is provided with an inlet section connected to the inlet, and the other end of the conveying channel is provided with a closed section. The radius of the circumference of the closed section is smaller than the radius of the circumference of the inlet section. The horizontal height of the closed section is higher than the horizontal height of the inlet section. The conveying channel is provided with an outlet along its length, and the direction of the outlet is opposite to the base.

2. The gas distributor for an ALD device according to claim 1, characterized in that, The cross-section of the conveying channel is circular.

3. The gas distributor for an ALD device according to claim 1, characterized in that, The number of loops in the conveying channel is 3 to 5.

4. The gas distributor for an ALD device according to claim 3, characterized in that, The spacing between the conveying channels in adjacent cycles is 2~8cm; Preferably, the pitch of the conveying channel is 1~5cm.

5. The gas distributor for an ALD device according to claim 1, characterized in that, The spacing between the air outlets is 1~5cm.

6. The gas distributor for an ALD device according to claim 1, characterized in that, The ratio between the diameter of the air outlet and the diameter of the conveying channel is 1:(0.03~0.5); Preferably, the diameter of the air outlet is 1~5mm, and the diameter of the conveying channel is 10~30mm.

7. The gas distributor for an ALD device according to claim 1, characterized in that, The gas source includes a carrier gas tank, a reaction gas tank, and a metal source precursor tank, and the number of each of the carrier gas tank, reaction gas tank, and metal source precursor tank is 1 to 3. Preferably, the gas in the carrier gas tank is argon and / or nitrogen; Preferably, the gas in the reaction tank is ammonia or ozone; Preferably, the metal source precursor container contains at least one of aluminum metal precursor, titanium metal precursor, molybdenum metal precursor, and nickel metal precursor.

8. The gas distributor for an ALD device according to claim 7, characterized in that, The air inlet is connected to the carrier gas tank, the reaction gas tank and the metal source precursor tank respectively; A first gas valve is installed on the connecting pipeline between the air inlet and the carrier gas tank to regulate the flow rate of the carrier gas entering the delivery channel; A second gas valve is installed on the pipeline connecting the gas inlet and the reaction gas tank to regulate the flow rate of the reaction gas entering the delivery channel. A third gas valve is installed on the pipeline connecting the air inlet and the metal source precursor tank to regulate the flow rate of the metal source precursor into the delivery channel.

9. A method for venting thin films grown on wafers by ALD, characterized in that, The ventilation method is implemented by the gas distributor for ALD equipment as described in any one of claims 1 to 8, and includes: placing the wafer on the substrate, heating it to the set reaction temperature, first introducing reaction gas A into the reaction chamber to undergo an adsorption reaction with the wafer surface, then introducing inert gas I for purging, then introducing reaction gas B into the reaction chamber to undergo a chemical reaction on the wafer surface, and then introducing inert gas II for purging, thus completing one growth cycle of thin film formation.

10. The ventilation method for growing thin films on wafers by ALD according to claim 9, characterized in that, The wafer has a diameter of 8 inches; Preferably, when the reaction gas A is ammonia or ozone, the reaction gas B contains a metal source precursor; or, when the reaction gas A contains a metal source precursor, the reaction gas B is ammonia or ozone. Preferably, both reaction gas A and reaction gas B are introduced into the reaction chamber in a pulsed manner; Preferably, the inert gas I and inert gas II are each independently argon and / or nitrogen; Preferably, the metal source precursor is selected from at least one of aluminum metal precursor, titanium metal precursor, molybdenum metal precursor, and nickel metal precursor; Preferably, the flow rate of ammonia or ozone is 100~1000 sccm, and the time is 20~40s; Preferably, when the reaction gas contains a metal source precursor, the reaction gas is introduced in a pulsed manner using inert gas III as the carrier gas, with an inert gas flow rate of 10~100 sccm and a duration of 0.5~1.0 s.

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