Furnace tube air outlet structure and method for improving film thickness uniformity and furnace tube device

Abstract

The invention discloses a furnace tube air outlet structure and method for improving film thickness uniformity and a furnace tube device. The initial size of each air outlet formed in a first process tube of an existing furnace tube is adjusted; the adjusted size of the air outlet hole is gradually reduced from any end of the first process pipe to the middle direction in the axial direction until the minimum adjusted size is intersected at one air outlet hole between the two ends of the first process pipe, so that the partial pressure of the process gas at the two ends of the first process pipe in the process is reduced; the problem of pressure rise at the two ends of the first process pipe due to the load effect is balanced, the pressure control stability of the furnace pipe process can be improved, the film thickness of a deposited film layer and the stability of components are improved, and therefore the uniformity between film thickness pieces of products in the same furnace can be effectively improved.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a furnace tube vent hole structure and method for improving film thickness uniformity, and a furnace tube device. Background Art

[0002] When using furnace tubes for atomic layer deposition, such as silicon nitride, the deposited film layer has good thickness uniformity (U%) and step coverage, and is widely used in advanced semiconductor processes.

[0003] See also Figure 1 . An existing furnace tube is provided with an outer tube 12 and an inner tube 11 of a double-layer structure. An air inlet 13 and an air outlet 14 are respectively provided on two opposite side walls of the inner tube 11 along the axial direction of the inner tube 11, and an exhaust port 15 is provided on the bottom of the side wall of the outer tube 12 corresponding to the air outlet 14. The inner tube 11 is used to place a wafer boat loaded with multi-layer products (chips or wafers). During the process, under the action of the negative pressure of the exhaust port 15, the process gas (precursor) entering the inner tube 11 through the air inlet 13 flows out through each air outlet 14, and converges into the exhaust port 15 to be discharged from the furnace tube. Among them, in order to maintain the consistency of the exhaust volume / pressure, the air outlet 14 is usually arranged in a manner that the size (area) gradually increases in the direction away from the exhaust port 15. Figure 2 The corresponding change in the opening area of ​​the air outlet 14 at different opening positions is shown (the horizontal axis direction in the figure is the opening position of the air outlet 14 away from the exhaust port 15).

[0004] When the above furnace tube is used to debug the deposition process of the control wafer, the film thickness has good intra-sheet uniformity (WiW U%), inter-sheet uniformity (WtW U%) and batch-to-batch uniformity (RtR U%) on the control wafer. However, in actual product production, due to the influence of the load effect on the furnace tube, the inter-sheet uniformity of the film thickness on the product is poor, and subject to the influence of the complex graphics on the product, the film thickness on the product at both ends of the furnace tube is relatively thicker, while the film thickness on the product in the middle of the furnace tube is relatively thinner. This phenomenon will become more obvious when the batch size in the same furnace is larger.

[0005] In order to solve the load effect, one method is to place dummy wafers near the upper and lower ends of the wafer boat, and only place the product wafer on the wafer boat between the two ends to avoid uneven film thickness caused by placing the product on both ends of the wafer boat. Figure 3However, since the baffle does not have a graphic structure, the surface area of ​​the product with a graphic structure is very different. The partial pressure of the precursor entering the furnace tube is higher at both ends of the furnace tube where the baffles are concentrated, making the film thickness on the product near this place thicker. The partial pressure of the precursor in the middle of the furnace tube where the products are concentrated is lower, making the film thickness on the product located here thinner. Therefore, the film thickness uniformity between the products in the same furnace will still be poor. Figure 4 The figure shows the change of film thickness (THK) of the corresponding product at different slots on the wafer boat (the horizontal axis in the figure is the slot position away from the exhaust port). Figure 5 The pressure loss ΔP at different opening positions caused by the load effect is shown (the horizontal axis in the figure is the position of the outlet opening away from the exhaust port).

[0006] At present, the countermeasures that can be taken include using a batch control system (Run to Run, RtR system) to provide different process cycle times for different batches to balance the loss of batch uniformity caused by the load effect, but it is difficult to improve the uniformity between product pieces in a single tube. Summary of the invention

[0007] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a furnace tube vent structure and method and a furnace tube device for improving the uniformity of film thickness.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] The present invention provides a furnace tube vent structure for improving film thickness uniformity, comprising:

[0010] A plurality of air outlet holes are axially arranged on the side wall of the first process tube, and the sizes of the air outlet holes are gradually reduced from any end of the first process tube to the middle direction along the axial direction until the minimum size intersects at an air outlet hole between the two ends of the first process tube, so as to reduce the partial pressure of the process gas at the two ends of the first process tube in the process, and balance the pressure increase problem at the two ends of the first process tube caused by the load effect.

[0011] Further, the sizes of the air outlet holes are different at two ends of the first process tube.

[0012] Further, the size of the air outlet at one end of the first process tube close to the exhaust port is smaller than that at the other end away from the exhaust port, and the exhaust port is located outside of one end close to the first process tube.

[0013] The present invention also provides a furnace tube device, including a double-layer process tube, wherein the double-layer process tube is provided with a first process tube and a second process tube covering the outer periphery of the first process tube, the side wall of the first process tube is provided with the above-mentioned furnace tube air outlet structure for improving the uniformity of film thickness and an air inlet structure opposite to the air outlet structure, the first process tube is used to place a crystal boat, a cavity is formed between the second process tube and the first process tube, an exhaust port is provided on one end of the second process tube, and the exhaust port is connected to the air outlet provided on the furnace tube air outlet structure through the cavity.

[0014] Furthermore, the exhaust port is correspondingly located on the bottom side wall of the second process tube on one side of the air outlet.

[0015] The present invention also provides a method for improving film thickness uniformity, comprising:

[0016] A furnace tube device is provided; the furnace tube device comprises a double-layer process tube, the double-layer process tube is provided with a first process tube and a second process tube covering the outer circumference of the first process tube, the first process tube is used to place a wafer boat, a plurality of air outlet holes are axially provided on the side wall of the first process tube, an exhaust port is provided on one end of the second process tube, and the air outlet holes are connected to the exhaust port through a cavity between the first process tube and the second process tube;

[0017] The initial size of the air outlet is adjusted to obtain the adjusted size of the air outlet, so that the adjusted size of the air outlet is set in a manner of gradually decreasing from any end of the first process tube to the middle direction along the axial direction until the minimum adjusted size intersects at an air outlet between the two ends of the first process tube, so as to reduce the partial pressure of the process gas at the two ends of the first process tube in the process, and balance the pressure increase problem at the two ends of the first process tube caused by the load effect.

[0018] Further, the adjusting the initial size of the air outlet to obtain the adjusted size of the air outlet specifically includes:

[0019] Obtaining the initial area of ​​each of the air outlet holes and the area of ​​the exhaust port;

[0020] Conducting a control sheet experiment, and adjusting the pressure at the exhaust port in each furnace process during the experiment, so as to obtain film layers of different thicknesses on the control sheet of each furnace, and obtaining different film thickness values ​​on the control sheet of each furnace;

[0021] Based on the premise that the film thickness of each control sheet in the same furnace is consistent, assuming that the pressure at each outlet hole in the process is equal, according to the formula that the suction force is equal to the product of pressure and area, and according to the suction force at the exhaust port being equal to the sum of the suction forces at each outlet hole, and the known initial area of ​​each outlet hole, the area of ​​the exhaust port and the pressure at the exhaust port, the average pressure of the control sheet at each outlet hole of each furnace is obtained, thereby establishing a corresponding relationship model between the film thickness and the pressure at the outlet hole;

[0022] Performing actual processing on the product, obtaining the film thickness value on each of the products in the same furnace, substituting the film thickness into the corresponding relationship model between the film thickness and the pressure at the vent, and using the obtained pressure value at the vent as the actual pressure of the product at each of the vents corresponding to the position of each of the products in the same furnace;

[0023] Substituting the target film thickness value of the product into the corresponding relationship model between the film thickness and the pressure at the air outlet, to obtain the corresponding target pressure value at each air outlet required for each product to reach the target film thickness;

[0024] Assuming that the suction at the exhaust port and the suction at each of the air outlets remain unchanged when the product is undergoing actual processing, the adjusted size of each of the air outlets is obtained based on the known initial area of ​​each of the air outlets, the actual pressure of the product at each of the air outlets, the target pressure value at each of the air outlets and the formula.

[0025] Furthermore, a pressure gauge is provided at the exhaust port to obtain the pressure at the exhaust port.

[0026] Furthermore, the process includes an atomic layer deposition process, the film layer is a film layer including the M element, and the pressure at the exhaust port is the pressure when a precursor containing the M element is introduced.

[0027] Furthermore, the M element includes Si element, and the film layer includes a SiOCN film layer.

[0028] It can be seen from the above technical scheme that the present invention adjusts the initial size of each air outlet on the first process tube (inner tube) of the existing furnace tube, so that the adjusted size of the air outlet is set in a manner of gradually decreasing from any end of the first process tube to the middle direction along the axial direction, until the minimum adjusted size intersects at an air outlet between the two ends of the first process tube, so as to reduce the partial pressure of the process gas at the two ends of the first process tube in the process, balance the pressure rise problem caused by the load effect at the two ends of the first process tube, increase the pressure control stability of the furnace tube process (such as atomic layer deposition process), improve the stability of the film thickness and composition of the deposited film layer, and thus effectively improve the uniformity of the film thickness between products in the same furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A schematic diagram of an existing air outlet structure of a furnace tube;

[0030] Figure 2 for Figure 1 Schematic diagram of the curve showing the change of the opening area of ​​the middle vent hole with the opening position of the vent hole;

[0031] Figure 3 The figure is a schematic diagram of a product loading method on a wafer boat; in the figure, Slot represents a slot, Dummy Wafer represents a baffle, and Product Wafer represents a product;

[0032] Figure 4 To adopt Figure 1 Schematic diagram of the film thickness variation curve of the product at different slots on the wafer boat when the furnace tube is used for the process; Slot in the figure represents the slot, and THK represents the film thickness;

[0033] Figure 5 To adopt Figure 1 Schematic diagram of the pressure loss ΔP curve at different opening positions caused by the load effect when the furnace tube is in process;

[0034] Figure 6 A schematic diagram of a furnace tube device and an air outlet structure thereof according to a preferred embodiment of the present invention;

[0035] Figure 7 The figure is a schematic diagram of a curve showing a change in the opening area of ​​an air outlet according to a preferred embodiment of the present invention as a function of the opening position of the air outlet. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0037] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0038] See also Figure 6 , Figure 6 FIG. 1 is a schematic diagram of a furnace tube device and its air outlet structure according to a preferred embodiment of the present invention. Figure 6As shown, a furnace tube vent structure for improving film thickness uniformity of the present invention comprises a plurality of vents 24 arranged on the side wall of a first process tube 21 (inner tube) of the furnace tube.

[0039] Among them, each gas outlet 24 is arranged on the side wall of the first process tube 21 along the axial direction (longitudinal direction in the figure) of the first process tube 21. In addition, the size of each gas outlet 24 is set in a manner of gradually decreasing from any end (upper and lower ends in the figure) of the first process tube 21 to the middle direction along the axial direction until the minimum size converges at a gas outlet 24 between the two ends of the first process tube 21 (that is, the one gas outlet 24 has the smallest opening size), so as to reduce the partial pressure of the process gas at the two ends of the first process tube 21 in the process, and balance the pressure rise problem caused by the load effect at the two ends of the first process tube 21.

[0040] In some embodiments, the size of the air outlet hole 24 may be an opening area of ​​the air outlet hole 24 .

[0041] In some embodiments, the shape of the air outlet 24 can be circular, polygonal, or irregular.

[0042] In some embodiments, the sizes of the gas outlet holes 24 at both ends of the first process tube 21 may be different. For example, the size of a first gas outlet hole 24 at the uppermost end of the first process tube 21 is different from the size of another first gas outlet hole 24 at the lowermost end of the first process tube 21. Further, the size of a second gas outlet hole 24 adjacent to the first gas outlet hole 24 at the upper end of the first process tube 21 is different from the size of another second gas outlet hole 24 adjacent to the first gas outlet hole 24 at the lower end of the first process tube 21. And so on.

[0043] In some embodiments, the size of the gas outlet 24 at one end of the first process tube 21 close to the exhaust port 25 is smaller than the size at the other end away from the exhaust port 25. For example, when the exhaust port 25 is located outside the lower end of the first process tube 21, the size of the first gas outlet 24 located at the uppermost end of the first process tube 21 is larger than the size of the other first gas outlet 24 located at the lowermost end of the first process tube 21. Further, the size of the second gas outlet 24 adjacent to the first gas outlet 24 located at the upper end of the first process tube 21 is larger than the size of the other second gas outlet 24 adjacent to the first gas outlet 24 located at the lower end of the first process tube 21. And so on.

[0044] See also Figure 6. A furnace tube device of the present invention comprises an inner and outer double-layer process tube 20, wherein the double-layer process tube 20 is provided with the above-mentioned first process tube 21 (inner tube), and a second process tube 22 (outer tube) covering the outer periphery of the first process tube 21. The side wall of the first process tube 21 is provided with the above-mentioned furnace tube air outlet structure for improving the uniformity of film thickness, and an air inlet structure 23 opposite to the air outlet structure. The air outlet structure is provided with the above-mentioned multiple air outlets 24; the air inlet structure 23 is provided with an air inlet. An exhaust port 25 is provided at, for example, the lower end of the second process tube 22. A closed cavity 26 is formed between the second process tube 22 and the first process tube 21; the exhaust port 25 is connected to each air outlet 24 through the cavity 26.

[0045] The first process tube 21 is used to place a wafer boat, and the wafer boat is provided with multiple slots, each of which is used to load a product (including a chip (wafer) product and a baffle).

[0046] In some embodiments, the exhaust port 25 is located on a bottom side wall of the second process tube 22 corresponding to one side of the exhaust hole 24 .

[0047] Furthermore, the cavity 26 is correspondingly disposed between the second process tube 22 and the first process tube 21 at the exhaust port 25 and the air outlet hole 24 .

[0048] During the process, under the negative pressure of the exhaust port 25 , the process gas (such as the precursor of the atomic layer deposition process) entering the first process tube 21 through the air inlet flows out through each of the air outlets 24 and converges into the exhaust port 25 to be discharged from the furnace tube.

[0049] Existing examples Figure 1 In order to keep the exhaust volume / pressure consistent, the exhaust holes 14 are usually arranged in a way that the size (area) gradually increases in the direction away from the exhaust port 15. At the same time, in order to solve the load effect, it is usually adopted to place baffles (Dummy Wafer) near the upper and lower ends of the wafer boat, and only place the product (Product Wafer) on the wafer boat position between the two ends (refer to Figure 3 ) to avoid uneven film thickness caused by placing products at both ends of the wafer boat. However, since the baffle does not have a pattern structure, the surface area is very different from that of the product with a pattern structure. The partial pressure of the precursor entering the furnace tube is higher at the two ends of the furnace tube where the baffles are concentrated, making the film thickness on the products near this place thicker, while the partial pressure of the precursor in the middle of the furnace tube where the products are concentrated is lower, making the film thickness on the products located there thinner, so the film thickness uniformity between the products in the same furnace will still be poor.

[0050] The present invention adjusts the initial size of each outlet hole 14 of the existing furnace tube, so that the adjusted size of the outlet hole 24 of the present invention is set in a manner of gradually decreasing from any end of the first process tube 21 to the middle direction along the axial direction, until the minimum adjusted size converges at an outlet hole 24 between the two ends of the first process tube 21, thereby forming a new outlet hole structure, which can reduce the partial pressure of the process gas at the two ends of the first process tube 21 in the process, so as to balance the pressure rise problem caused by the load effect at the two ends of the first process tube 21. Therefore, the improved outlet hole structure of the present invention can increase the pressure control stability of the furnace tube process (such as the atomic layer deposition process), improve the stability of the film thickness and composition of the deposited film layer, and effectively improve the uniformity of the film thickness between the products of the same furnace.

[0051] A method for improving film thickness uniformity of the present invention is further described in detail below through specific implementations and in conjunction with the accompanying drawings.

[0052] See also Figure 1 and Figure 6 A method for improving film thickness uniformity of the present invention comprises:

[0053] First, provide an existing furnace tube device. For example, you can use Figure 1 An existing furnace tube device is shown. The existing furnace tube device is provided with an inner tube 11 (corresponding to Figure 6 The first process tube 21), and the outer tube 12 (corresponding to the outer tube 12) covered on the outer periphery of the inner tube 11 Figure 6 The second process tube 22) forms an inner and outer double-layer process tube (corresponding to Figure 6 The inner tube 11 is used to place the wafer boat. The side wall of the inner tube 11 is provided with a plurality of air outlet holes 14 along the axial direction (corresponding to the air outlet holes 24 on the air outlet hole structure of the present invention after the size adjustment). The side wall of the inner tube 11 opposite to the air outlet holes 14 is provided with an air inlet hole 13 along the axial direction. The side wall of the outer tube 12, for example, at the lower end is provided with an exhaust port 15 (corresponding to Figure 6 A closed cavity 16 (corresponding to the exhaust port 25) is formed between the outer tube 12 and the inner tube 11. Figure 6 The exhaust port 15 is connected to the air outlet 14 through the cavity 16. The exhaust port 15 may be provided with a pressure gauge VG1.

[0054] Then, the initial size of the air outlet 14 is adjusted to obtain the adjusted size of the air outlet 14, and the adjusted size of the air outlet 14 is set in a manner of gradually decreasing from any end of the inner tube 11 to the middle direction along the axial direction until the minimum adjusted size converges at an air outlet 14 between the two ends of the inner tube 11, thereby forming a new air outlet structure and its air outlet 24 of the present invention, so as to reduce the partial pressure of the process gas at the two ends of the inner tube 11 (first process tube 21) in, for example, the atomic layer deposition process, and balance the pressure rise problem at the two ends of the inner tube 11 caused by the load effect.

[0055] The specific method of adjusting the initial size of the air outlet 14 to obtain the adjusted size of the air outlet 14 to form the new air outlet 24 structure of the present invention may include the following steps:

[0056] Step 1: For example Figure 1 The existing furnace tube device can obtain the initial area S of each outlet hole 14 by measuring 1 , S 2 , …, S n , and the area S of the exhaust port 15 0 . The subscripts 1, 2, ..., n represent the opening position sequence of the air outlet 14 (for example, the air outlets 14 can be numbered from bottom to top on the inner tube 11, that is, the first air outlet 14 located at the bottom of the inner tube 11 is numbered 1, which is closest to the exhaust port 15, and the first air outlet 14 located at the top of the inner tube 11 is numbered n, which is farthest from the exhaust port 15), and 0 represents the number of the exhaust port 15 (the same below). The following further describes the pressure as P, the suction as F, and the film thickness as THK.

[0057] Step 2: Place the control wafer at the position used to place the product in the wafer boat, conduct a multi-furnace process experiment on the control wafer, and in each furnace process during the experiment, the pressure P at the exhaust port 15 is 0 Adjustments are made to obtain film layers of different thicknesses on the control sheets of each furnace, and different film thickness values ​​on the control sheets of each furnace can be obtained by measurement.

[0058] When conducting a control sheet (a sheet without a pattern structure on the surface) experiment, the same atomic layer deposition process cycle count is set to perform each furnace process. In addition, when conducting experiments with different furnaces, different pressures P at the exhaust port 15 are used. 0The process is carried out so that the pressure at each outlet 14 in different furnaces also changes accordingly. In this way, different thicknesses of film layers can be obtained on the control sheets of different furnaces. Among them, the experiment should include a control sheet experiment furnace (batch) using the same pressure at the exhaust port 15 as that in normal product production, and use the pressure at the exhaust port 15 as a reference. Within the range allowed by the process, the pressure at the exhaust port 15 is increased or decreased to obtain different thicknesses of film layers on the control sheets of different furnaces, and the film layer thickness range on the control sheets of each furnace obtained in the control sheet experiment can cover the maximum fluctuation range of the film layer thickness formed on each product in the same furnace during normal product production.

[0059] The pressure at the exhaust port 15 can be obtained by setting a pressure gauge VG1 at the exhaust port 15. In addition, the pressure at the exhaust port 15 obtained is the displayed value of the pressure gauge VG1 at the exhaust port 15 when the main precursor is introduced in the atomic layer deposition process of each furnace. For example, when the film layer is a compound film layer of the M element, the pressure at the exhaust port 15 is the pressure when the precursor containing the M element is introduced. In one example, the M element may include the Si element, and the film layer may include a SiOCN film layer, then the pressure at the exhaust port 15 is the displayed value of the pressure gauge VG1 at the exhaust port 15 when the precursor containing the Si element is introduced.

[0060] Step 3: Based on the premise that the film thickness of each control piece in the same furnace is consistent, it is assumed that the pressure at each outlet 14 in the process is equal. According to the formula that suction is equal to the product of pressure and area, and according to the suction at the exhaust port 15 being equal to the sum of the suction at each outlet 14, and the known initial area of ​​each outlet 14, the area of ​​the exhaust port 15 and the pressure at the exhaust port 15, the average pressure of the control piece at each outlet 14 of each furnace is obtained, thereby establishing a corresponding relationship model between film thickness and pressure at the outlet.

[0061] Existing examples Figure 1 In the furnace tube device shown, under the condition of the initial size of the outlet hole 14, when the control slice experiment is carried out, the consistency of the thickness of the film deposited on each control slice in the same furnace is very high, that is, it has a high degree of uniformity between slices. Therefore, it can be considered that the pressure at each outlet hole 14 in the process is equal, that is: P 1 =P 2 =…=P n =P old Among them, P old It represents the average pressure at each air outlet 14.

[0062] Suppose there is a formula: F=PS.

[0063] Among them, the suction force F at the exhaust port 15 is 0 (Total suction force) is equal to the sum of the suction forces at each air outlet 14, that is:

[0064] F 0 =F 1 +F 2 +…+F n . Then we have:

[0065] P 0 S 0 =P old (S 1 +S 2 +…+S n ).

[0066] Among them, S 0 , S 1 ~S n All have been measured, P 0 In each furnace experiment, the pressure gauge VG1 at the exhaust port 15 can be used to read the pressure, so P can be calculated by the above formula old , that is, the average pressure of the control sheet at each outlet 14 in each furnace experiment. Since the thickness of the film deposited on each control sheet in the same furnace is uniform (can be regarded as equal), the P of each furnace can be old As the actual pressure at any outlet 14 required to obtain the corresponding film thickness on the furnace control sheet. In this way, the actual pressure P at the outlet 14 is calculated by the different film thickness THK on the control sheet of each furnace. old , the corresponding relationship between the vent pressure and the film thickness can be determined, and the corresponding relationship between the pressure and the film thickness of the vent 14 obtained by the control experiment is used in the actual product process as the corresponding relationship between the film thickness of the deposited film layer on each product in the same furnace and the pressure at the corresponding vent 14, thereby establishing a corresponding relationship model between the film thickness and the pressure at the vent for actual products:

[0067] P i产品 =f(THK).

[0068] Where, i = 1 to n (the same below), P i产品 With P old correspond.

[0069] That is, the actual pressure on the product during production (reflected by the pressure at the corresponding air outlet 14) can be inferred from the film thickness on the product through the above model.

[0070] Step 4: Carry out actual processing on the product, obtain the film thickness value on each product in the same furnace, substitute it into the corresponding relationship model between film thickness and pressure at the vent, and use the obtained pressure value at the vent 14 as the actual pressure of the product at each vent 14 corresponding to the position of each product in the same furnace.

[0071] By carrying out actual processing on products (chips or wafer products with graphic structures on the surface) and measuring the film thickness values ​​on each product in the same furnace, the film thickness data of the film layer on each product is substituted into the above model, and the pressure (P) at an outlet hole 14 on the inner tube 11 corresponding to each product in the same furnace can be obtained. i产品 ), thereby obtaining the actual product pressure P at each outlet 14 1产品 , P 2产品 ,…,P n产品 .

[0072] At the same time, the target film thickness value of the product (i.e., the process setting value) is substituted into the above model to obtain the corresponding target pressure value P at each outlet required for each product to achieve the target film thickness. 目标 (When the film thickness of each product in the same furnace is consistent, the target pressure value at each outlet is equal).

[0073] Step 5: Assume that the suction force at the exhaust port 15 and the suction force at each outlet hole 14 remain unchanged during the actual process of the product. According to the known initial area S of each outlet hole 14 1 ~S n , the actual product pressure P at each outlet 14 i产品 , Target pressure value P at each outlet 目标 And the formula F=PS, the adjusted size of each air outlet 14 is obtained.

[0074] Usually, the total suction force at the exhaust port 15 is constant during normal product production. In order to ensure the stability of the film thickness, assuming that the suction force at each outlet 14 is also constant, then according to the above formula F=PS, we can have:

[0075] F i =S i P i产品 =S inew P 目标 .

[0076] Among them, S inew The adjusted area size of each air outlet hole 14 is shown.

[0077] That is, S 1 P 1产品 =S 1new P 目标 , S 2 P 2产品 =S 2new P 目标 , …, S n P n产品 =S nnew P 目标 .

[0078] Due to S i , P i产品, P 目标 are all known, so the adjusted area S of each air outlet 14 can be obtained inew . That is, we get Figure 6 The improved gas outlet hole 24 of the present invention and the furnace tube device of the present invention having the improved gas outlet hole 24 structure are shown.

[0079] Software fitting can be used to obtain more accurate results that meet the requirements for uniformity of film thickness between slices.

[0080] Figure 7 The simulation result of the curve of the change of the opening area of ​​the air outlet 24 (the adjusted area of ​​the air outlet 14) on the furnace tube device of the present invention obtained according to the above method with the opening position of the air outlet 24 is shown (the horizontal axis direction in the figure is the opening position of the air outlet 24 away from the exhaust port 25). Figure 2 The initial area of ​​the air outlet 14 shown in FIG. Figure 5 The pressure loss ΔP caused by the load effect shown in is comprehensively considered and formed by superimposing the two curves (the specific opening area of ​​the air outlet 24 can be obtained by the method for improving the uniformity of film thickness of the present invention).

[0081] After studying the existing Figure 1 The initial size of each air outlet 14 is adjusted as above, and the following is obtained: Figure 6 The improved air outlet 24 of the present invention and the furnace tube device of the present invention containing the improved air outlet 24 structure shown in the figure can reduce the partial pressure of the process gas at both ends of the first process tube 21 in the process, and balance the pressure unevenness problem at each air outlet 24 caused by the pressure increase at both ends of the first process tube 21 due to the load effect. Therefore, the pressure control stability of the furnace tube process (such as the atomic layer deposition process) can be increased, and the stability of the film thickness and composition of the deposited film layer can be improved, thereby effectively improving the uniformity of the film thickness between products in the same furnace.

[0082] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A furnace tube vent structure for improving film thickness uniformity, It is characterized in that include: A plurality of air outlet holes are axially arranged on the side wall of the first process tube, and the sizes of the air outlet holes are gradually reduced from any end of the first process tube to the middle direction along the axial direction until the minimum size intersects at an air outlet hole between the two ends of the first process tube, so as to reduce the partial pressure of the process gas at the two ends of the first process tube in the process, and balance the pressure increase problem at the two ends of the first process tube caused by the load effect.

2. The furnace tube vent structure for improving film thickness uniformity according to claim 1, It is characterized in that The sizes of the gas outlet holes are different at two ends of the first process tube.

3. The furnace tube vent structure for improving film thickness uniformity according to claim 2, It is characterized in that The size of the gas outlet hole at one end of the first process tube close to the exhaust port is smaller than that at the other end away from the exhaust port, and the exhaust port is located outside of one end of the first process tube.

4. A furnace tube device, It is characterized in that The invention comprises a double-layer process tube, wherein the double-layer process tube is provided with a first process tube and a second process tube covering the outer periphery of the first process tube, the side wall of the first process tube is provided with a furnace tube air outlet structure for improving the uniformity of film thickness as described in any one of claims 1 to 3 and an air inlet structure opposite to the air outlet structure, the first process tube is used for placing a crystal boat, a cavity is formed between the second process tube and the first process tube, an exhaust port is provided on one end of the second process tube, and the exhaust port is connected to the air outlet provided on the furnace tube air outlet structure through the cavity.

5. The furnace tube device according to claim 4, It is characterized in that The exhaust port is correspondingly located on the bottom side wall of the second process tube at one side of the air outlet.

6. A method for improving film thickness uniformity, It is characterized in that include: Provide furnace tube device; The furnace tube device comprises a double-layer process tube, wherein the double-layer process tube is provided with a first process tube and a second process tube covering the outer circumference of the first process tube, wherein the first process tube is used to place a wafer boat, a plurality of air outlet holes are axially provided on the side wall of the first process tube, an exhaust port is provided on one end of the second process tube, and the air outlet holes are connected to the exhaust port through a cavity between the first process tube and the second process tube; The initial size of the air outlet is adjusted to obtain the adjusted size of the air outlet, so that the adjusted size of the air outlet is set in a manner of gradually decreasing from any end of the first process tube to the middle direction along the axial direction until the minimum adjusted size intersects at an air outlet between the two ends of the first process tube, so as to reduce the partial pressure of the process gas at the two ends of the first process tube in the process, and balance the pressure increase problem at the two ends of the first process tube caused by the load effect.

7. The method for improving film thickness uniformity according to claim 6, It is characterized in that The adjusting the initial size of the air outlet to obtain the adjusted size of the air outlet specifically includes: Obtaining the initial area of ​​each of the air outlet holes and the area of ​​the exhaust port; Conducting a control sheet experiment, and adjusting the pressure at the exhaust port in each furnace process during the experiment, so as to obtain film layers of different thicknesses on the control sheet of each furnace, and obtaining different film thickness values ​​on the control sheet of each furnace; Based on the premise that the film thickness of each control sheet in the same furnace is consistent, assuming that the pressure at each outlet hole in the process is equal, according to the formula that the suction force is equal to the product of pressure and area, and according to the suction force at the exhaust port being equal to the sum of the suction forces at each outlet hole, and the known initial area of ​​each outlet hole, the area of ​​the exhaust port and the pressure at the exhaust port, the average pressure of the control sheet at each outlet hole of each furnace is obtained, thereby establishing a corresponding relationship model between the film thickness and the pressure at the outlet hole; Performing actual processing on the product, obtaining the film thickness value on each of the products in the same furnace, substituting the film thickness into the corresponding relationship model between the film thickness and the pressure at the vent, and using the obtained pressure value at the vent as the actual pressure of the product at each of the vents corresponding to the position of each of the products in the same furnace; Substituting the target film thickness value of the product into the corresponding relationship model between the film thickness and the pressure at the air outlet, to obtain the corresponding target pressure value at each air outlet required for each product to reach the target film thickness; Assuming that the suction at the exhaust port and the suction at each of the air outlets remain unchanged when the product is undergoing actual processing, the adjusted size of each of the air outlets is obtained based on the known initial area of ​​each of the air outlets, the actual pressure of the product at each of the air outlets, the target pressure value at each of the air outlets and the formula.

8. The method for improving film thickness uniformity according to claim 7, It is characterized in that By arranging a pressure gauge at the exhaust port, the pressure at the exhaust port is obtained.

9. The method for improving film thickness uniformity according to claim 7, It is characterized in that The process includes an atomic layer deposition process, the film layer is a film layer including the M element, and the pressure at the exhaust port is the pressure when a precursor containing the M element is introduced.

10. The method for improving film thickness uniformity according to claim 9, It is characterized in that The M element includes Si element, and the film layer includes a SiOCN film layer.

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