Plasma processing device capable of realizing rapid gas switching

Abstract

The utility model provides a plasma processing device capable of realizing rapid switching of gas, which comprises a processing chamber provided with an edge gas inlet structure; the dielectric window is arranged at the top of the processing chamber, and the dielectric window is provided with a spraying plate; the gas conveying system comprises a first process gas conveying pipeline and a second process gas conveying pipeline which are independently arranged; wherein the first process gas conveying pipeline is divided into a first gas channel and a second gas channel through a first gas distribution device, the first gas channel is communicated with a gas inlet of the spraying plate, and the second gas channel is communicated with a gas inlet of the edge gas inlet structure; the second process gas conveying pipeline is divided into a third gas channel and a fourth gas channel through a second gas distribution device, the third gas channel is communicated with the gas inlet of the spraying plate, and the fourth gas channel is communicated with the gas inlet of the edge gas inlet structure. The plasma gas switching device is used for shortening the switching period between different plasma gases.

Description

TECHNICAL FIELD

[0001] The utility model relates to a semiconductor equipment technical field, especially a kind of plasma processing device for realizing gas quick switching. BACKGROUND

[0002] Plasma etching process has become an important technology in the field of semiconductor processing, and with the increasing demand for etching process, cyclic etching becomes a trend, such as Bosch process. During deposition, fluorocarbon-containing plasma gas is introduced into the reaction chamber, which can form fluorocarbon-based polymer, deposited on the sidewall and bottom of the wafer, playing a role in sidewall passivation. In the etching process, fluorine-containing gas enters the reaction chamber to form plasma, and due to anisotropic etching, the protective film on the bottom is removed, and further etching the bottom, while the polymer protective film on the sidewall accumulates a new layer of protective film before it disappears, and this process is repeated alternately, forming a high aspect ratio trench. Therefore, in the deep silicon etching process, it is necessary to realize the continuous switching of deposition gas plasma and etching gas plasma. The switching period between the deposition gas plasma stage and the etching gas plasma stage determines the quality of the final etching process. Generally speaking, the faster the switching period, the better the process adjustability, and the better the high aspect ratio and depth uniformity.

[0003] The gas path design in the prior art is relatively complex, involving the use of multiple valves, which not only increases the cost, but also affects the switching period of the gas quick switching. And there is a long shared pipeline between the two kinds of gas, which leads to the mixing of one kind of process gas with the other kind of process gas remaining in the pipeline before entering the processing chamber, which is not expected to happen in the process. UTILITY MODEL CONTENT

[0004] The utility model aims to provide a kind of plasma processing device for realizing gas quick switching, for shortening the switching period between different plasma gas.

[0005] To achieve the above purpose, the utility model realizes the following technical scheme: a kind of plasma processing device for realizing gas quick switching, comprising:

[0006] processing chamber, the processing chamber is equipped with edge gas inlet structure;

[0007] dielectric window, the dielectric window is arranged at the top of processing chamber, and the dielectric window is equipped with spray plate;

[0008] gas delivery system, including independently arranged first process gas delivery pipeline and second process gas delivery pipeline;

[0009] pump, the pump is connected with the bottom of processing chamber;

[0010] The first process gas delivery pipeline is divided into a first gas passage and a second gas passage through a first gas distribution device, the first gas passage is communicated with the gas inlet of the shower plate, and the second gas passage is communicated with the gas inlet of the edge gas inlet structure.

[0011] The second process gas delivery pipeline is divided into a third gas passage and a fourth gas passage through a second gas distribution device, the third gas passage is communicated with the gas inlet of the shower plate, and the fourth gas passage is communicated with the gas inlet of the edge gas inlet structure.

[0012] Optionally, the first gas passage and the second gas passage are respectively provided with a first valve and a second valve; the first gas distribution device is respectively provided with a first gas suction pipeline between the first valve and the second valve, the gas suction pipeline is provided with a first gas suction valve, and the first gas suction pipeline is connected with a pump.

[0013] Optionally, the third gas passage and the fourth gas passage are respectively provided with a third valve and a fourth valve; the second gas distribution device is respectively provided with a second gas suction pipeline between the third valve and the fourth valve, the gas suction pipeline is provided with a second gas suction valve, and the second gas suction pipeline is connected with a pump.

[0014] Optionally, the distance between the first valve and the third valve and the gas passage of the gas inlet of the shower plate is 3-20 cm.

[0015] Optionally, the distance between the second valve and the fourth valve and the gas passage of the gas inlet of the edge gas inlet structure is 1-10 cm.

[0016] Optionally, the first valve, the second valve, the third valve, the fourth valve, the first gas suction valve and the second gas suction valve are all quick switching valves.

[0017] Optionally, the shower plate is circular, and the shower plate comprises an annular gas inlet area located in the center of the circle.

[0018] Optionally, the annular gas inlet area comprises at least two groups of annularly distributed gas hole groups, each group of the gas hole groups has 20-50 axially extending gas holes.

[0019] Optionally, the edge gas inlet structure is an annular gas inlet disc, and the annular gas inlet disc is provided with circumferentially uniformly distributed gas inlet passages.

[0020] Optionally, the annular gas inlet disc is located between the processing chamber and the dielectric window, the annular gas inlet disc comprises opposite top surface and bottom surface, and inner side surface and outer side surface connecting the top surface and the bottom surface; the top surface of the annular gas inlet disc is opposite to the dielectric window, and the bottom surface of the annular gas inlet disc is opposite to the processing chamber; the gas inlet channel of the annular gas inlet disc has one end as a gas inlet and the other end as a gas outlet; the gas inlet is located on the outer side surface, and the gas outlet is located on the inner side surface.

[0021] Compared with the prior art, the utility model has the advantages of:

[0022] (1) the first process gas conveying pipeline and the second process gas conveying pipeline are independently arranged, and are communicated with the gas inlet of the spraying plate and the gas inlet of the edge gas inlet structure respectively, so that the mixing of different process gases before entering the processing chamber is avoided.

[0023] (2) the utility model optimizes the pipeline structure of the process gas entering the processing chamber, shortens the distance between the gas inlet valve and the gas inlet, shortens the residence time of the process gas in the pipeline, and accelerates the rapid switching of the gas.

[0024] (3) the utility model changes the original two independent gas suction pipelines into one gas suction pipeline, and the number of the rapid switching valves is reduced through the control of one rapid switching valve, so that the cost is reduced.

[0025] (4) the utility model improves the structure of the original gas inlet nozzle, increases the edge gas inlet structure, optimizes the uniformity of the gas flow field, and further improves the uniformity of the etching of the wafer surface. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme of the utility model, the following will briefly introduce the drawings needed to be used in the description, and obviously, the drawings in the following description are one embodiment of the utility model, and for the ordinary skilled in the art, other drawings can be obtained without creative labor:

[0027] Figure 1 It is an embodiment of the utility model about the plasma processing device for realizing the rapid switching of the gas.

[0028] Figure 2 It is a bottom view of the dielectric window of the utility model.

[0029] Figure 3 It is a schematic view of the edge gas inlet structure of the utility model. DETAILED DESCRIPTION

[0030] The utility model discloses the scheme makes further detailed explanation below combining the drawing and specific embodiment. According to the following description, the advantages and characteristics of the utility model will be more clear. It needs to be explained that the drawing adopts very simplified form and all uses non-precise proportion, just to facilitate, clear and brightly assist the purpose of the explanation of the embodiment of the utility model. In order to make the purpose, characteristics and advantages of the utility model more obvious and easy to understand, please refer to the drawing. It is known that the structure, proportion, size etc. shown in the drawing of this specification are just to cooperate the content disclosed in the specification, to be understood and read by the person skilled in the art, and not to limit the limiting conditions of the implementation of the utility model, so it does not have the substantial meaning of technology, any modification of structure, change of proportion relationship or adjustment of size, under the condition of not influencing the effect and the purpose that the utility model can produce, should still fall in the range that the technical content disclosed in the utility model can cover.

[0031] The utility model discloses a kind of plasma processing device for realizing gas rapid switching, which can realize the rapid switching of deposition gas plasma and etching gas plasma in wafer etching process.

[0032] Figure 1 It is shown that according to the plasma processing device for realizing gas rapid switching of an embodiment of the utility model, including processing chamber 21, the processing chamber is equipped with edge gas inlet structure 22;Dielectric window 23, the dielectric window is arranged at the top of processing chamber, and the dielectric window is equipped with spray plate 24, for uniformly introducing reaction gas into processing chamber;Gas delivery system, including independently arranged first process gas delivery pipeline 25 and second process gas delivery pipeline 26;Pump, the pump is connected with the bottom of processing chamber, for discharging gas after reaction from processing chamber;Wherein, the first process gas delivery pipeline 25 is divided into first gas passage 251 and second gas passage 252 by first gas distribution device 250, the first gas passage 251 is communicated with the gas inlet of spray plate 24, and the second gas passage 252 is communicated with the gas inlet of edge gas inlet structure 22;The second process gas delivery pipeline 26 is divided into third gas passage 261 and fourth gas passage 262 by second gas distribution device 260, the third gas passage 261 is communicated with the gas inlet of spray plate 24, and the fourth gas passage 262 is communicated with the gas inlet of edge gas inlet structure 22.

[0033] Specifically, the top of the dielectric window is provided with a coil structure 27, which is connected to a high-frequency radio frequency source 28 through a wire. The high-frequency radio frequency source is used to output radio frequency power of a certain frequency, such as 13 MHz radio frequency power. The coil is divided into an inner coil and an outer coil, and the coil is used to generate an electromagnetic field to couple and generate plasma in the processing chamber.

[0034] An electrostatic chuck 29 is located within the processing chamber. It is used to position the wafer and secure it to the chuck's surface through high-voltage adsorption. The chuck houses a built-in RF electrode, which is connected to a bias source 30. This bias source 30 outputs a RF bias voltage at a specific frequency, such as 400 kHz. This bias voltage is applied to the RF electrode of the electrostatic chuck and generates a self-bias on the wafer, accelerating ion bombardment of the wafer surface.

[0035] The gas delivery system enters the processing chamber through a shower plate 24 located on the dielectric window 23 and an inlet structure 22 at the edge of the processing chamber. Ionization occurs under the influence of the electromagnetic field to generate plasma. An exhaust port is also located below the processing chamber 21, connected to a pump 31 for extracting the reactant gases from the reaction chamber.

[0036] The first process gas may be an etching gas, which is distributed to different areas of the processing chamber 21 according to the flow ratio through the first gas distribution device 250, such as the middle area and the edge area of ​​the processing chamber. The etching gas includes Ar, O2, CO, CO2, H2, C x F y or C x F y H z (wherein x, y and z are any integers), and the type of etching gas is not limited.

[0037] The second process gas can be a deposition gas, which is distributed to different areas of the processing chamber according to the flow ratio through the second gas distribution device 260, for example, to the middle area of ​​the processing chamber and the edge area of ​​the processing chamber. The deposition gas can be a small hydrocarbon molecule gas of C1 to C5, or a polymer-generating gas such as carbonyl sulfide gas, and the type of deposition gas is not limited.

[0038] like Figure 1 As shown, the first process gas is divided into two paths through the first gas distribution device 250. The first gas distribution device is a gas splitter. The two gases enter the first gas channel 251 and the second gas channel 252 respectively. The first gas channel 251 is provided with a first valve 253. When the first valve is opened, the first process gas enters the processing chamber 21 through the spray plate 24 located on the medium window; the second gas channel 252 is provided with a second valve 254. When the second valve is opened, the first process gas enters the processing chamber 21 through the air intake structure 22 located at the edge of the processing chamber.

[0039] The first process gas is communicated with a first exhaust pipeline 255 at the front end of the first valve and the second valve, the first exhaust pipeline 255 is provided with a first exhaust valve 256, the first exhaust pipeline 255 is communicated with the pump 31, and the first process gas can be exhausted.

[0040] The second process gas is divided into two paths through a second gas distribution device 260, the second gas distribution device is a gas flow divider, the two paths of gas enter a third gas channel 261 and a fourth gas channel 262 respectively, the third gas channel 261 is provided with a third valve 263, the second process gas enters the processing chamber through the spray plate 24 located at the medium window by opening the third valve, and the fourth gas channel is provided with a fourth valve 264, the second process gas enters the processing chamber 21 through the edge gas inlet structure 22 located at the processing chamber by opening the fourth valve.

[0041] The second process gas is communicated with a second exhaust pipeline 265 at the front end of the third valve and the fourth valve, the second exhaust pipeline is provided with a second exhaust valve 266, the second exhaust pipeline is communicated with the vacuum pump 31, and the second process gas can be exhausted.

[0042] The first process gas and the second process gas are divided into independent gas inlet channels to enter the processing chamber, and there is no shared gas pipeline before entering the processing chamber, so that the mixing of the two different gases before entering the processing chamber can be avoided to the greatest extent.

[0043] The first exhaust valve controls the exhaust of the two paths of the first process gas, the second exhaust valve controls the exhaust of the two paths of the second process gas, the number of valves is effectively reduced under the condition that the function is unchanged, and the cost is reduced.

[0044] The gas channel distance between the first valve and the third valve and the gas inlet port of the spray plate is 3-20 cm, and the gas channel distance between the second valve and the fourth valve and the gas inlet port of the edge gas inlet structure is 1-10 cm. By shortening the distance between the gas inlet valve and the gas inlet port, the residence time of the process gas in the pipeline can be effectively reduced, and the switching period of different process gases can be shortened.

[0045] The first valve, the second valve, the third valve, the fourth valve, the first exhaust valve and the second exhaust valve are all fast switching valves, such as ALD valves, and the gas switching time is less than 10 ms. By adopting the fast switching valve, the switching period of different process gases can also be shortened.

[0046] As shown in Figure 2 The medium window center region is provided with a spray plate, the spray plate is circular, the spray plate includes an annular gas inlet area 31 located in the center of the circle, the dielectric window center is provided with a mounting through hole 32, and the mounting through hole can be mounted with a probe for end point detection.

[0047] The annular gas inlet area 31 comprises at least two groups of annularly distributed gas hole groups, each of the gas hole groups having 20 to 50 axially extending gas holes 33. The first process gas and the second process gas enter the processing chamber through the gas holes, which can be circular, elliptical or other shapes, without limitation. The process gas can be made to quickly pass through the shower plate into the processing chamber by designing the gas hole diameter, shortening the residence time of the process gas in the shower plate and shortening the gas switching time.

[0048] As shown in Figure 3 The edge gas inlet structure is an annular gas inlet disc, which is provided with circumferentially uniformly distributed gas inlet channels 41.

[0049] The annular gas inlet disc is located between the processing chamber and the dielectric window, and comprises opposite top and bottom surfaces, and inner and outer side surfaces connecting the top and bottom surfaces; the top surface of the annular gas inlet disc is opposite to the dielectric window, and the bottom surface of the annular gas inlet disc is opposite to the processing chamber; one end of the gas inlet channel of the annular gas inlet disc is a gas inlet, and the other end is a gas outlet; the gas inlet is located on the outer side surface, and the gas outlet is located on the inner side surface. Further, a sealing ring is arranged between the annular gas inlet disc and the dielectric window, and a sealing ring is also arranged between the annular gas inlet disc and the sidewall of the processing chamber.

[0050] Through the design of the shower plate located at the center of the dielectric window and the edge gas inlet structure, the process gas can enter through the center and the edge of the processing chamber at the same time, and through the gas distribution device, the process gas entering the shower plate and the edge gas inlet structure can be set to have different proportions, effectively adjusting the flow field uniformity of the plasma region of the processing chamber, and realizing multi-zone adjustment of gas distribution. The shower plate and the edge gas inlet structure can be designed by reasonably designing the hole and distribution to reduce the gas flow resistance, so that the first process gas can quickly replace the second process gas in the plasma region of the processing chamber, shortening the switching period between different plasmas.

[0051] It is to be noted that, in the present document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element. Additionally, the term "coupled" is defined as connected, whether directly or indirectly, while the term "connected" is defined as directly or indirectly connected. In the document, the term "optional" means that the feature can or can not be present, and that the process, method, article, or apparatus can or can not include the feature.

[0052] Although the present application has been described in detail through the preferred embodiments, it should be understood that the above description is not to be considered as limiting the present application. Various modifications and alterations of the present application will become apparent to those skilled in the art from the above description without departing from the scope of the present application. Accordingly, the scope of the present application should be determined by the appended claims and their equivalents.

Claims

1. A plasma processing device for realizing rapid gas switching, characterized in that: include: a processing chamber, wherein the processing chamber is provided with an edge air intake structure; a dielectric window, the dielectric window being arranged at the top of the processing chamber and provided with a shower plate; The gas delivery system includes a first process gas delivery pipeline and a second process gas delivery pipeline that are independently arranged; a pump connected to the bottom of the processing chamber; The first process gas delivery pipeline is divided into a first gas channel and a second gas channel through a first gas distribution device, the first gas channel is connected to the air inlet of the shower plate, and the second gas channel is connected to the air inlet of the edge air inlet structure; The second process gas delivery pipeline is divided into a third gas channel and a fourth gas channel through a second gas distribution device. The third gas channel is connected to the air inlet of the shower plate, and the fourth gas channel is connected to the air inlet of the edge air inlet structure.

2. A plasma processing device for realizing rapid gas switching according to claim 1, characterized in that: The first gas channel and the second gas channel are respectively provided with a first valve and a second valve; a first exhaust pipeline is respectively provided between the first gas distribution device and the first valve and the second valve, the exhaust pipeline is provided with a first exhaust valve, and the exhaust pipeline is connected to a pump.

3. The plasma processing device for realizing rapid gas switching according to claim 2, characterized in that: The third gas channel and the fourth gas channel are respectively provided with a third valve and a fourth valve; a second exhaust pipeline is respectively provided between the second gas distribution device and the third valve and the fourth valve, the exhaust pipeline is provided with a second exhaust valve, and the exhaust pipeline is connected to a pump.

4. The plasma processing device for realizing rapid gas switching according to claim 3, characterized in that: The first valve and the third valve are 3 to 20 cm away from the gas channel of the air inlet of the shower plate.

5. The plasma processing device for realizing rapid gas switching according to claim 4, characterized in that: The distance between the second valve and the fourth valve and the gas channel of the air inlet of the edge air inlet structure is 1 to 10 cm.

6. The plasma processing device for realizing rapid gas switching according to claim 5, characterized in that: The first valve, the second valve, the third valve, the fourth valve, the first air extraction valve and the second air extraction valve are all fast switching valves.

7. The plasma processing device for realizing rapid gas switching according to claim 1, characterized in that: The spray plate is circular and includes an annular air inlet area located in the center of the circle.

8. The plasma processing device for realizing rapid gas switching according to claim 7, characterized in that: The annular air inlet area includes at least two annularly distributed air hole groups, and each of the air hole groups has 20 to 50 axially extending air holes.

9. The plasma processing device for realizing rapid gas switching according to claim 1, characterized in that: The edge air intake structure is an annular air intake disk, and the annular air intake disk is provided with air intake channels evenly distributed in the circumferential direction.

10. The plasma processing device for realizing rapid gas switching according to claim 9, characterized in that: The annular air inlet disk is located between the processing chamber and the dielectric window. The annular air inlet disk includes opposing top and bottom surfaces, and inner and outer side surfaces connecting the top and bottom surfaces. The top surface of the annular air inlet disk is opposite to the dielectric window, and the bottom surface of the annular air inlet disk is opposite to the processing chamber. One end of the air inlet channel of the annular air inlet disk is an air inlet, and the other end is an air outlet. The air inlet is located on the outer side, and the air outlet is located on the inner side.

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