Semiconductor processor and air supply system thereof

Abstract

According to the gas supply system provided by the invention, each gas supply main pipeline is formed by connecting one or more three-way valves with the upstream purified gas valve in series, each gas source is connected to the branch main pipelines (131 and 132) through the second gas inlet of each three-way valve, and no longer connecting pipeline is arranged between the gas source and the main pipeline to form a dead zone; therefore, in the purification process, all residual gas flowing through the previous step can be washed away by the purification gas. In addition, the precursor gas B and the precursor gas C which can generate violent reaction are respectively arranged in the two branch main pipelines connected by the gating valve, so that thorough isolation of the two gases is realized, and even if residual gas is still in one branch main pipeline in the purification process, the residual gas cannot be diffused to the other branch main pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a gas supply system for a tungsten deposition process, which can reduce particulate pollution during the tungsten deposition of a wafer to be processed. Background Art

[0002] A large number of wafer processing devices are required in the field of integrated circuit manufacturing to perform various processings on wafers. Among them, the deposition of tungsten in the holes or grooves formed by etching is a key structure for realizing the connection between semiconductor devices and the upper copper interconnection layer. The above deposition process is also widely used in the manufacture of multi-layer horizontal electrodes in 3D NAND memories. The tungsten filling process can be as disclosed in Patent CN115172268A submitted by the same applicant. First, an isolation layer (TiN) is formed in the hole or long groove, then a very thin tungsten nucleation layer is formed on the isolation layer, and finally the remaining space in the whole hole is filled with a tungsten bulk layer. Among them, the tungsten nucleation layer usually adopts the gas supply system of atomic layer deposition (ALD), and the tungsten material layer is grown layer by layer through multiple consecutive gas supply cycles of switching the supply gas. The tungsten bulk layer can adopt the process of chemical vapor deposition (CVD), and gradually grow on the nucleation layer until the target thickness is reached. When the filling consistency requirement is high, the atomic layer deposition process can also be adopted. Among them, the tungsten growth step of the nucleation layer and the tungsten growth step of the bulk are usually carried out in the same reaction chamber, and most of the reaction gases are shared, only a small part of the reaction gases are different.

[0003] Such as Figure 1Shown is a gas supply system used in a prior art processor, including a processing chamber. The processing chamber includes a heating base 10, and a wafer W to be processed is disposed on the base. At the top of the processing chamber opposite to the wafer, there is a gas showerhead 20. An exhaust ring 12 is further included outside the gas showerhead 20 for exhausting by-product gases formed after the reaction. The gas supply system includes a main gas supply pipe 30, the lower end of which is connected to the gas showerhead 20. During the upward extension of the main pipe 30, it is sequentially connected to each gas source supply pipe through a plurality of switching valves. For example, it is connected to the pipe 33 for supplying precursor gas B through valve V2b, connected to the gas supply pipe 32 for precursor gas A through valve V2a, and further includes a valve V2p at the far end. The purge gas supply pipe 31 is connected to the main pipe 30 through valve V2p. During atomic layer deposition, sequential supply is required: precursor A - purge - precursor B - purge. After the supply of precursor A is completed during the process, valve V2a is closed, and the remaining precursor A gas in the main pipe is emptied by flowing the purge gas through the main pipe 30. Then, precursor gas B is introduced into the reaction chamber through the main pipe 30. In the above gas supply structure, there are two dead zones Sd between valves V2b and V2a and the main pipe. Therefore, during the purification process, the purge gas cannot effectively flush the residual gas in the dead zones, which will cause the residual of precursor gas A and precursor gas B to be premixed and react in the main pipe 30 in advance. The by-products formed by these reactions become pollution sources and are introduced into the reaction chamber and fall onto the wafer to form particles on the wafer, seriously affecting the yield of the wafer.

[0004] Therefore, the industry needs to develop a new gas supply system to eliminate dead zones, prevent the pre-mixing of different reaction gases during the switching process, and reduce particulate pollutants. Summary of the Invention

[0005] The object of the present invention is to provide a gas supply system for a semiconductor processor used in the ALD process, which is characterized in that it includes: a plurality of gas supply three-way valves, each gas supply three-way valve includes a first inlet, a second inlet and an outlet; a first purge gas valve and a plurality of three-way valves are connected in series with each other to form a first main gas supply pipe; a second purge gas valve and one or more three-way valves are connected in series with each other to form a second main gas supply pipe; among the three-way valves connected in series, the outlet of the upstream three-way valve is connected to the first inlet of the downstream three-way valve; one end of the purge gas valve is used to connect to a purge gas supply source, and the other end is connected to the first inlet of the downstream and adjacent three-way valve; in the first main gas supply pipe, the second inlet of the upstream three-way valve is used to connect to a first reaction gas source, the second inlet of the downstream three-way valve is connected to the outlet end of the second main gas supply pipe, and the outlet of the lowermost three-way valve is connected to an output pipe for outputting gas to the semiconductor processor.

[0006] Optionally, the first main gas supply pipe includes at least three three-way valves connected in series with each other, and the second air inlets of two of the three-way valves are connected to the first reaction gas source and the second reaction gas source. The second air inlets of the three three-way valves are sequentially connected to the first reaction gas source, the outlet end of the second main gas supply pipe, and the second reaction gas source.

[0007] Optionally, the second main gas supply pipe includes a plurality of three-way valves connected in series, and the second air inlets of at least two three-way valves are used to connect to the second reaction gas source and the third reaction gas source.

[0008] The present invention also provides a semiconductor processor, which includes a reaction chamber and a pedestal located at the bottom inside the reaction chamber. The pedestal is used to support the substrate to be processed. The top opposite to the pedestal includes a gas shower head, and further includes the gas supply system as described in claim 1. The output pipe of the gas supply system is connected to the gas shower head, and further includes a controller for controlling the opening and closing states of the respective purification gas valves and three-way valves. Description of the Drawings

[0009] Figure 1 is a schematic structural diagram of a processor in the prior art;

[0010] Figure 2 is a schematic structural diagram of a processor and its gas supply system of the present invention;

[0011] Figure 3 is a schematic diagram of the process of alternating gas flow during the deposition of the nucleation layer tungsten in the present invention;

[0012] Figure 4 is a schematic diagram of the process of alternating gas flow during the deposition of the bulk layer tungsten in the present invention;

[0013] Figure 5 is a schematic diagram of another embodiment of the gas supply system of the present invention. Detailed Embodiments

[0014] The following further describes in detail a wafer carrier device and a chemical vapor deposition apparatus proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and are all drawn with non-precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features, and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical substance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0015] As Figure 2 shown is a partial enlarged view of the processing device of the present invention, and its basic structure is the same as Figure 1Similar to the processor shown, the gas supply system includes two branch main pipes 131 and 132. One end of the first branch main pipe 131 is connected to the gas source of the purified gas 1, and the other end is connected to the gas shower head 20 in the processing chamber through the output pipe 135. One end of the second branch main pipe 132 is connected to the gas source of the purified gas 2, and the other end is connected to the second intake port of a selection valve V3s at the downstream end of the first branch main pipe 131. The selection valve V3s is a three-way valve. Each three-way valve has three ports shown as V3c in the figure, and each port is connected to its respective intake or outlet channel, namely the first intake port 101, the second intake port 102, and the outlet port 103. The three-way valve V3s further includes a first intake port connected to the upstream of the first branch main pipe 131, and a downstream outlet port connected to the output pipe 135. The upstream end of the first branch main pipe 131 includes a valve Vp1. The opening or closing of the valve Vp1 enables its outlet port to selectively supply the purified gas downstream. The valve Vp1 can be a single-channel valve or a three-way valve, but one of the channels is in a closed state for a long time. The first intake port of a first gas supply three-way valve V3a is connected to the outlet port of the valve Vp1, the second intake port is connected to the precursor gas A, and its outlet port is connected to the first intake port of the downstream second gas supply three-way valve V3b. The second intake port of the second gas supply three-way valve V3b is connected to the gas source of the precursor gas B, and its outlet port is connected to the first intake port of the selection valve V3s. The upstream end of the second branch main pipe 131 includes a valve Vp2, whose structure and function are basically the same as those of the valve Vp1. Its intake port is connected to the gas source of the purified gas 2, and its outlet port is connected to the first intake port of a third gas supply three-way valve V3c. The valve Vp1 and the valve Vp2 can be respectively connected to different purified gas sources or to the same purified gas source. As long as the two valves can respectively allow the high-pressure purified gas to flow through the respective first branch main pipe 131 and the second branch main pipe 132 by opening and closing, the object of the invention can be achieved. The second intake port of the third gas supply three-way valve V3c is connected to the gas source of the precursor gas C, and its outlet port is connected to the second intake port of the selection valve V3s.

[0016] The first and second branch main pipelines 131 and 132 in the present invention include a long strip-shaped body made of metal. A communication pipeline 101 and 103 that are inclined downward in sequence are provided inside the body. There is an opening exposed on the upper surface of the long strip-shaped body between the communication pipelines. All the various valves described in the present invention are installed on the opening, so that each valve and each communication pipeline are connected in series to form a gas supply pipeline. Among them, the three-way valves all include a driving control part located above. The driving control part includes a pneumatic or electric driving mechanism to quickly drive the valve body in the opening of the lower body to move. The driving control part is hermetically fixed to the upper surface of the first and second branch main pipelines through a connecting part. The valve body is located in the air flow channel of the first and second branch main pipelines. By moving the valve body to different positions, any one of the first air inlet, the second air inlet, and the air outlet in the three-way valve can be opened or closed as needed.

[0017] The present invention is mainly applied to atomic layer deposition of tungsten, especially in the manufacturing of 3D NAND memories, to fill the nucleation layer tungsten and the bulk layer tungsten in the vertically stacked long grooves formed in the multi-layer overlapping materials. The precursor gas A of the present invention can be a reducing gas such as H2, the precursor gas B can be WF6 or other tungsten-containing raw material gases, and the precursor gas C can be borane or silane. Among them, the precursor gas A and the precursor gas B are generally used to generate the tungsten bulk layer, and the precursor gas C and the precursor gas B are generally used to generate the tungsten nucleation layer. The reaction between the precursor gas C and B is violent, and even a very small amount of mixing may cause a reaction to form pollutant particles, so it is necessary to strictly avoid the mixing of the two in the gas supply system.

[0018] When performing the growth of the nucleation layer tungsten, the precursor gas C supply step, the precursor gas C purification step, the precursor B supply step, and the precursor B purification step are performed in sequence. First is the precursor gas C supply step. Control the selection valve V3s to conduct the second air inlet, and at the same time control the second air inlet of the third gas supply three-way valve V3c to be opened, so that the precursor gas C passes through the invention V3c, V3s and the pipeline 135 to reach the gas spray head 20; then open the air inlet of the valve Vp2 so that the purification gas 2 flows through all the pipelines through which the precursor gas C flows to achieve purification. Subsequently, enter the precursor B supply step: Select the valve V3s to close its second air inlet connected to the pipeline 133, open the first air inlet, and at the same time open the second air inlet of the second gas supply three-way valve V3b, so that the precursor gas B passes through the valve V3b, V3s and the pipeline 135 to reach the spray head 120; finally, perform the precursor gas B purification step, close the second air inlet of the valve V3b, and at the same time open the air inlet of the valve Vp1, so that the purification gas 1 flows through all the pipelines through which the precursor gas B flows. After multiple cycles, the growth of the nucleation layer tungsten is completed, and the subsequent tungsten bulk layer growth process is entered. As Figure 3 Shown is a schematic diagram of the process of alternately supplying different gases to the gas spray head when performing the growth of the nucleation layer.

[0019] When performing the process of growing a tungsten bulk layer, the selector valve V3s selects to supply only the gas from the first branch main pipe 131 while closing the gas from the second branch main pipe 132. First, the second air inlet of the first gas supply three-way valve V3a is selectively opened, while the second air inlet on the second gas supply three-way valve V3b is closed, so that the precursor gas flows through the valves V3a, V3b, V3s and the pipe 135 in sequence to reach the downstream gas shower head for reaction. Then, in the purification step, the valve Vp1 is opened and the second air inlet of the first gas supply three-way valve V3a is closed, so that all the residual precursor gas A in the first branch main pipe 131 is flushed out. Then, in the precursor gas B supply step, the second air inlet on the second gas supply valve V3b is opened and the second air inlet on the first gas supply three-way valve V3a is closed, so that the precursor gas B is supplied into the reaction chamber. Finally, the purification step is performed again to flush the inside of the pipe through which the precursor gas B flows with the purification gas, completing the current cycle and entering the next cycle again. As Figure 4 It is a schematic diagram of the process of alternately supplying different gases to the gas shower head when performing the growth of the bulk layer.

[0020] In the gas supply system proposed by the present invention, since each gas supply main pipe is formed by connecting one or more three-way valves in series with the upstream purification gas valve, and each gas source is connected to the main pipes (131, 132) through the second air inlets of the respective three-way valves, there is no long connecting pipe between the gas source and the main pipe to form a dead zone. Therefore, in the purification process, the purification gas can flush out all the residual gases flowing through in the previous step. In addition, since the precursor gas B and the precursor gas C that will undergo a violent reaction are respectively arranged in two branch main pipes connected by the selector valve V3S, the two gases are completely isolated. Even if there are still residues in the purification process, they are in one branch main pipe and will not spread to the other branch main pipe.

[0021] The valves V3a and V3b in the present invention can also be only arranged downstream of the second branch main pipe 132. In this way, the precursor gases A and B are both supplied to the selector valve V3s located on the first branch main pipe 131 through the connecting pipe 133', and then supplied to the gas shower head through the output pipe 135'. At the same time, the valve V3c can be arranged upstream of the selector valve V3s on the first branch main pipe 131. Such a structure can also achieve the object of the present invention, complete the ALD growth while avoiding the generation of particulate pollutants. As Figure 5 The schematic diagram of the gas supply system of this modified embodiment is shown. The gas supply system proposed by the present invention can be used not only for the above-mentioned ALD tungsten growth process, but also for the ALD processes of other materials such as TiN.

[0022] In the present invention, other gas supply three-way valves can also be added in the middle of the first branch main pipeline to supply other gases required by the process. Similarly, additional gas supply three-way valves can be added downstream of the valve Vp2 in the second branch main pipeline to supply new process gases. For example, V2c can be divided into two valves V3c1 and V3c2, and each valve is respectively connected to a silane gas source and a borane gas source. As long as all the gas supply three-way valves are connected in series with each other to form a unique gas supply path, the advantage of thorough purification of the present invention can be achieved. In addition, in the present invention, V3s does not necessarily have to be located at the most downstream of the first branch main pipeline 131. The inlet of the precursor gas B shared by the two processes can be set downstream of the selected valve V3s, and the other two precursor gases A and C are still located upstream of the two branch main pipelines. Under this gas supply system structure, the tungsten deposition process for the bulk layer can also be carried out, so it also belongs to the variant embodiments of the present invention.

[0023] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A gas supply system for a semiconductor processor, characterized in that, Comprising: Multiple gas supply three-way valves, each gas supply three-way valve including a first air inlet, a second air inlet, and an air outlet; The first purified gas valve and multiple three-way valves are connected in series with each other to form a first main gas supply pipeline; The second purified gas valve and one or more three-way valves are connected in series with each other to form a second main gas supply pipeline; Wherein, for the three-way valves connected in series with each other, the air outlet of the upstream three-way valve is connected to the first air inlet of the downstream three-way valve; one end of the purified gas valve is used to connect to the purified gas supply source, and the other end is connected to the first air inlet of the downstream and adjacent three-way valve; In the first main gas supply pipeline, the second air inlet of the upstream three-way valve is used to connect to the first reaction gas source, the second air inlet of the downstream three-way valve is connected to the air outlet end of the second main gas supply pipeline, and the air outlet of the lowermost downstream three-way valve is connected to an output pipeline for outputting gas to the semiconductor processor.

2. The gas supply system according to claim 1, wherein The first main gas supply pipeline includes at least three three-way valves connected in series with each other, wherein the second air inlets of two three-way valves are connected to the first reaction gas source and the second reaction gas source.

3. The air supply system according to claim 1, characterized in that The second main gas supply pipeline includes multiple three-way valves connected in series, and the second air inlets of at least two three-way valves are used to connect to the second reaction gas source and the third reaction gas source.

4. The air supply system as shown in claim 2, characterized in that, The second air inlets of the three three-way valves are sequentially connected to the first reaction gas source, the air outlet end of the second main gas supply pipeline, and the second reaction gas source.

5. The gas supply system according to claim 1, characterized in that, The first reaction gas source is a tungsten-containing gas, and the reaction gas sources connected to the three-way valves in the second main gas supply pipeline include silane or borane.

6. The air supply system according to claim 1, characterized in that The purified gas valve is a single-pass valve.

7. The gas supply system according to claim 1, characterized in that, The first and second main gas supply pipelines include a long strip-shaped body, and multiple openings spaced apart from each other are included above the body. The openings are connected by inclined downward connecting pipelines, and each three-way valve is installed on the openings such that each valve and each connecting pipeline are connected in series to form a gas supply path.

8. The gas supply system according to claim 7, wherein, The valve includes a driving part and a connecting part located above the body, and a valve body located in the opening. The driving part is used to drive the valve body so that the first air inlet, the second air inlet, and the air outlet of the valve are selectively opened or closed.

9. A semiconductor processor, the semiconductor processor including a reaction chamber and a base located at the bottom inside the reaction chamber. The base is used to support the substrate to be processed, and the top opposite to the base includes a gas shower head. The semiconductor processor further includes the gas supply system as claimed in claim 1. The output pipeline of the gas supply system is connected to the gas shower head, and further includes a controller for controlling the on / off states of the respective purified gas valves and three-way valves.

10. The semiconductor processor according to claim 9, wherein, In the process executed by the semiconductor processor, it includes a first step: the lowermost downstream three-way valve in the first main gas supply pipeline of the gas supply system closes the first air inlet, so that the second reaction gas and the purified gas from the second main gas supply pipeline pass through the second air inlet and the air outlet of the lowermost downstream three-way valve in sequence and are output to the processor.

11. The semiconductor processor according to claim 10, characterized in that, It further includes a second step: the three-way valve at the most downstream closes the second air inlet, so that the first reaction gas and the purification gas from the upstream of the first main gas supply pipeline pass through the first air inlet and the air outlet of the three-way valve at the most downstream and are output to the processor successively.

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