Liquid pumping control method for precursor container of thin film deposition equipment

Abstract

The invention discloses a liquid pumping control method for a precursor container of thin film deposition equipment. The liquid pumping control method comprises the following steps: introducing reaction gas into a thin film deposition chamber; introducing a chemical source into the thin film deposition cavity; judging whether the precursor container needs to be supplemented with liquid or not; if yes, supplementing a chemical source into the precursor container; and if not, starting radio frequency to perform a thin film deposition process. According to the liquid injection control method for the precursor container of the thin film deposition equipment, the cycle number is counted, liquid injection treatment is carried out according to the cycle number, and the cycle number and the process coverage rate have a specific relation, so that the liquid injection state of the precursor container is more stable, and the process performance of the thin film deposition process is more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid replenishment control in semiconductor equipment, and in particular to a liquid injection control method for a precursor container of a thin film deposition equipment. Background Art

[0002] In order to solve the problems of film thickness and particle stability, the way of liquid injection of precursors in the ALD (atomic layer deposition) process of the semiconductor industry has become increasingly important. As the ALD process proceeds, the liquid level in the precursor cylinder will be gradually consumed, and the volume of the vaporized precursor above the liquid will increase in the cylinder. Under the condition of the same carrier gas passing through, the change in volume will cause the state of the precursor to be unstable during liquid injection, which will lead to unstable process performance. Therefore, it is necessary to add liquid to the cylinder during the process to ensure the relative dynamic balance of the internal environment of the cylinder.

[0003] At present, the main method of liquid replenishment is triggered by the change of the liquid level in the cylinder. However, in the continuous process, the relationship between the process performance and the liquid level is a complex dynamic change. It is difficult to make the process more stable by only controlling the liquid level. Therefore, a method that can flexibly trigger liquid replenishment during the process is needed. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for controlling the liquid injection of a precursor container of a thin film deposition device, so as to solve the technical problem that the existing liquid level control liquid replenishment method cannot adapt to dynamic changes in the process.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An embodiment of the present invention provides a method for controlling liquid injection of a precursor container of a thin film deposition device, comprising the following steps:

[0007] introducing a reaction gas into a thin film deposition chamber;

[0008] introducing a chemical source into the thin film deposition chamber;

[0009] Determine whether the precursor container needs to be refilled;

[0010] If yes, then add chemical source to the precursor container;

[0011] Otherwise, the radio frequency is turned on to carry out the thin film deposition process.

[0012] Among them, in the step of judging whether the precursor container needs to be replenished, it is determined by counting the number of consecutive execution cycles of a complete thin film deposition process and the corresponding process coverage.

[0013] The number of cycles and the corresponding process coverage satisfy the following formula:

[0014] θ is the process coverage, α is a constant related to the reaction materials and reaction conditions, N is the number of cycles performed, and P is the gas pressure at this time.

[0015] The process coverage θ is not less than the minimum coverage required by the process.

[0016] The pressure P is determined by the following formula:

[0017]

[0018] Where θ is the process coverage and b is the adsorption constant.

[0019] Wherein, the precursor container is a steel cylinder.

[0020] Wherein, if so, the step of replenishing the chemical source into the precursor container also includes automatically clearing the number of cycles N that have been performed.

[0021] The control method further includes cyclically executing the step of determining whether the precursor container needs to be replenished and the subsequent steps.

[0022] Among them, the control method is applied to atomic layer deposition process.

[0023] The liquid injection control method for the precursor container of the thin film deposition equipment of the present invention counts the number of cycles and performs liquid replenishment processing according to the number of cycles. In addition, there is a specific relationship between the number of cycles and the process coverage, thereby making the liquid injection state of the precursor container more stable and the process performance of the thin film deposition process more stable.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flowchart of a method for controlling liquid injection of a precursor container of a thin film deposition device according to an embodiment of the present invention.

[0026] Figure 2 It is a schematic diagram of the uniformity comparison test results of the liquid injection control method of the precursor container of the thin film deposition equipment according to the embodiment of the present invention.

[0027] Figure 3 It is a schematic diagram of the comparison test results of the average thickness growth in each cycle of the liquid injection control method of the precursor container of the thin film deposition equipment according to the embodiment of the present invention.

[0028] Figure 4 It is a schematic diagram of the particle quantity comparison test results of the liquid injection control method of the precursor container of the thin film deposition equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships described in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0036] In order to solve the problems of film thickness and particle stability, the way of liquid injection of precursors in the ALD process of the semiconductor industry has become increasingly important. As the ALD process proceeds, the liquid level in the precursor cylinder will be gradually consumed. At this time, the volume of the vaporized precursor above the liquid will increase in the cylinder. Under the condition of the same carrier gas passing through, the change in volume will cause the state of the precursor to be unstable during liquid injection, which will lead to unstable process performance. Therefore, it is necessary to add liquid to the cylinder during the process to ensure the relative dynamic balance of the internal environment of the cylinder.

[0037] At present, the main method of refilling is triggered by the change of the liquid level in the cylinder. However, in the continuous process, the relationship between the process performance and the liquid level is a complex dynamic change. It is difficult to make the process more stable only by a single liquid level control. Therefore, a method that can flexibly trigger refilling during the process is needed. Based on the above requirements, this embodiment provides a method for controlling the liquid injection of a precursor container of a thin film deposition device.

[0038] When the liquid level in the precursor container drops (i.e., the amount of gas decreases), the pressure P will also decrease if the temperature and volume remain unchanged. The relationship is shown in the following formula:

[0039] PV=nRT

[0040] (P is the gas pressure; V is the gas volume; n is the number of moles of gas; R is the gas constant; T is the gas temperature)

[0041] In addition, for the ALD process, a decrease in gas pressure P will lead to a decrease in gas flow Q, which will directly affect the deposition rate of the ALD process. The relationship is as follows:

[0042]

[0043] (P is the gas pressure; C is the flow coefficient related to the equipment structure; Q is the gas flow rate; ρ is the gas density)

[0044] The adsorption efficiency of the ALD (atomic layer deposition) process is usually positively correlated with the gas flow rate, that is, when the gas flow rate decreases, the adsorption efficiency will decrease, which will cause the ALD process performance to change.

[0045] Since the process performance can also be reflected by the deposition adsorption coverage. Under certain conditions, the adsorption of the precursor can approximately follow the Langmu ir adsorption isotherm. The basic relationship is:

[0046]

[0047] (where θ is the adsorption coverage, b is the adsorption constant, and P is the gas pressure)

[0048] It can be seen from the corresponding relationship that with the increase of pressure P, the adsorption coverage θ will also become higher and higher, and can be close to 100% to a certain extent. The adsorption constant b can be regarded as a constant under the same process conditions. However, b is different for different processes. Under normal circumstances, the higher the adsorption coverage, the smaller the impact on process performance. However, there is also a range, that is, under the premise of not less than a minimum coverage value, the process performance does not change significantly.

[0049] See also Figure 1 Based on the above process theory, this embodiment discloses a liquid injection control method for a precursor container of a thin film deposition device, and the liquid injection control method for a precursor container of a thin film deposition device includes the following steps:

[0050] Step 1: introducing reaction gas, that is, the gas required for the thin film deposition reaction, into the thin film deposition chamber; the reaction gas required varies depending on the process.

[0051] Step 2: introducing a chemical source into the thin film deposition chamber, i.e., injecting liquid;

[0052] Step 3: Determine whether the precursor container needs to be replenished; according to the needs of different processes, the amount of liquid in the precursor container needs to be maintained within a certain threshold range. If it is lower than the minimum threshold, it will affect the process stability and quality.

[0053] Step 4: If yes, then add the chemical source to the precursor container; in this step, a diaphragm valve can be used to control the on / off of the infusion pipeline of the chemical source container connected to the precursor container for rapid replenishment.

[0054] Step 5: If not, start the radio frequency to carry out the thin film deposition process. If no liquid replenishment is needed at present, that is, it meets the minimum requirement of process coverage, then start the radio frequency to carry out radio frequency reaction to produce a thin film to complete a thin film deposition process.

[0055] Step 6: Repeat steps 3 to 5 until the process is completed. In a continuous thin film deposition process, after completing a complete thin film deposition process cycle, the next cycle of the process will be performed again. Each time a process is started, it is necessary to first determine whether liquid replenishment is required. A complete cycle refers to the surface atomic layer deposition of a wafer.

[0056] Among them, in the step of judging whether the precursor container needs to be replenished, the number of cycles of a complete thin film deposition process continuously executed and the corresponding process coverage is determined. The number of cycles is the number of times the thin film deposition process is continuously executed. For example, the thin film deposition on the surface of a wafer is one cycle, and the number of cycles is the number of times the above process is continuously executed.

[0057] Specifically, the number of cycles and the corresponding process coverage satisfy the following formula:

[0058] θ is the process coverage, α is a constant related to the reaction materials and reaction conditions, N is the number of cycles performed, and P is the gas pressure at this time.

[0059] The process coverage θ is not less than the minimum coverage required by the process. In the atomic layer deposition process, as long as the coverage is not less than the minimum threshold, it will not affect the quality of thin film deposition. Therefore, the process coverage θ here is generally set based on the minimum requirement. Of course, in order to improve its process stability, the process coverage θ can also be selected at any other value above its minimum value.

[0060] Wherein, the pressure value P is determined by the following formula:

[0061]

[0062] Wherein, θ is the process coverage, and b is the adsorption constant. When the number of liquid injection cycles is initially determined, the θ value takes its minimum value, that is, according to the corresponding process requirements, under the condition of minimum coverage, the process quality requirements are still met.

[0063] In this embodiment, the precursor container is a steel cylinder.

[0064] Furthermore, if the chemical source is added to the precursor container, the step 4 also includes automatically clearing the number of cycles N that have been performed. After clearing, the cyclic refilling judgment is performed again to continue multiple thin film deposition processes. After completing a refilling, it is generally possible to continue multiple cycles of thin film deposition again, so it is necessary to automatically clear the statistical value of the number of cycles at the software layer in the control.

[0065] In this embodiment, the precursor container replenishment control method of the semiconductor device is applied to the atomic layer deposition process, that is, the ALD process.

[0066] This technical solution is mainly aimed at the ALD process formula. The ALD process steps are simply shown in the following flow chart. After the process starts, the gas required for the reaction is introduced, and then the chemical source (liquid) is introduced, and then the radio frequency is activated to react and produce a thin film. The steps of introducing the chemical source and activating the radio frequency are one cycle. The ALD reaction can control the thickness of the film by controlling the number of cycles. That is to say, a certain amount of chemical source will be consumed in each cycle.

[0067] The control method of this embodiment adds a step of whether to trigger liquid replenishment in the mature ALD process formula steps. The step of detecting the number of cycles of the process that has been performed is added to the steps, and the detection method can use software counting. Setting the number of cycles that have been performed can reflect the liquid level consumed by the cylinder at this time. As the number of cycles increases, the pressure of the incoming gas gradually decreases, that is, the adsorption coverage rate of the process is also gradually decreasing. Moreover, the adsorption coverage rate of many ALD processes does not necessarily require a very high level to ensure the stability of the process, so a cycle number can be set according to the adsorption coverage rate required by different requirements to trigger liquid replenishment.

[0068] For example, if the coverage of a process is above 60%, it will not affect the process performance. Through this coverage, based on the above formula, a number of cycles that have been performed, 2000, can be obtained. This 2000 is set in the step of detecting whether to trigger the rehydration. During the process of the cycle in the process step, each time the step is executed, the software count is used to detect whether it has reached 2000. If it has reached, rehydration will be performed, and the accumulated number of cycles will be cleared when the rehydration is successful. If the trigger condition, that is, the set number of cycles, is not reached, the rehydration step will be skipped and the normal process step will be performed.

[0069] Please refer again Figures 2 to 4 The improved process of this embodiment improves the effectiveness of each liquid injection. The state of the steel cylinder is closer to dynamic balance and more stable. Therefore, when injecting liquid into the precursor container in the process step, it is more stable, so that the process performance such as film thickness and particles is more stable.

[0070] like Figures 2 to 4The data is a comparison of the uniformity of the process, the average thickness growth in each cycle, and the number of particles. After multiple tests and verifications, it is found that the process method of this embodiment, when used to trigger the refilling, is more stable and has less fluctuation than the existing liquid level triggering, which is conducive to improving the process quality.

[0071] The liquid injection control method for the precursor container of the thin film deposition equipment of this embodiment counts the number of cycles and performs liquid replenishment processing according to the number of cycles. In addition, there is a specific relationship between the number of cycles and the process coverage, thereby making the liquid injection state of the precursor container more stable and the process performance of the thin film deposition process more stable.

[0072] The above examples are only used to further illustrate the technical content of the present invention, so that readers can understand it more easily, but it does not mean that the implementation of the present invention is limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for controlling the liquid injection of a precursor container of a thin film deposition device, characterized in that: The following steps are involved: introducing a reaction gas into a thin film deposition chamber; introducing a chemical source into the thin film deposition chamber; Determine whether the precursor container needs to be refilled; If yes, then add chemical source to the precursor container; Otherwise, the radio frequency is turned on to carry out the thin film deposition process.

2. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 1, characterized in that: In the step of judging whether the precursor container needs to be replenished, the number of consecutive execution cycles of a complete thin film deposition process and the corresponding process coverage are counted to determine.

3. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 2, characterized in that: The number of cycles and the corresponding process coverage satisfy the following formula: θ is the process coverage, α is a constant related to the reaction materials and reaction conditions, N is the number of cycles performed, and P is the gas pressure value.

4. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 3, characterized in that: The process coverage θ is not less than the minimum coverage required by the process.

5. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 3, characterized in that: The pressure value P is determined by the following formula: Where θ is the process coverage and b is the adsorption constant.

6. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 3, characterized in that: The precursor container is a steel cylinder.

7. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 3, characterized in that: If yes, the step of replenishing the chemical source into the precursor container also includes automatically clearing the counted number of cycles N.

8. The method for controlling liquid injection of a precursor container of a thin film deposition device according to any one of claims 1 to 7, characterized in that: The control method also includes cyclically executing the step of determining whether the precursor container needs to be replenished and the subsequent steps.

9. The method for controlling liquid injection of a precursor container of a thin film deposition device according to claim 7, characterized in that: The control method is applied to atomic layer deposition process.

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