CN218868424U

CN218868424U - Microwave resonant cavity

Info

Publication number: CN218868424U
Application number: CN202223101373.7U
Authority: CN
Inventors: 乐卫平; 黄永镇; 郭蕾
Original assignee: Shenzhen CSL Vacuum Science and Technology Co Ltd
Current assignee: Shenzhen CSL Vacuum Science and Technology Co Ltd
Priority date: 2022-11-22
Filing date: 2022-11-22
Publication date: 2023-04-14
Anticipated expiration: 2032-11-22

Abstract

The utility model belongs to the microwave field relates to a microwave resonant cavity, include: the microwave cavity comprises a resonant cavity, a dielectric window and a vacuum cavity, wherein the resonant cavity is of a centrosymmetric structure formed by splicing multiple sections of waveguides, a plurality of slits are formed in the bottom wall of the resonant cavity, and microwave energy is uniformly fed into the vacuum cavity through the dielectric window. (1) The resonant cavity is provided with a centrosymmetric structure, and a plurality of slits are arranged on the bottom wall of the resonant cavity, so that microwave energy can be uniformly fed into the vacuum cavity through the dielectric window by the resonant cavity, and large-area uniform surface wave plasma is generated in the vacuum cavity; at the same time, the slits ensure stability in feeding microwave energy into the vacuum chamber to excite the formation of a plasma. (2) The adjustable central deposition table which can move in the vertical direction is arranged, so that the state of the plasma can be optimally adjusted, and the uniformity of the deposited film is improved.

Description

Microwave resonant cavity

Technical Field

The utility model relates to a microwave technical field, in particular to microwave resonant cavity.

Background

In recent years, with the rapid development of electronic technology, the general trend of the demand for integrated circuits tends to be highly integrated and larger in area, which requires that enterprises producing integrated circuits continuously increase the processing capability of semiconductor wafers. Plasma devices are not substitutable in the manufacturing process of Integrated Circuits (ICs). Therefore, the development of high-performance plasma generation equipment is crucial to the development of semiconductor manufacturing processes. When the plasma equipment is used in a semiconductor manufacturing process, the most important factors to be investigated are: can generate plasma with large area and uniformity efficiently in a certain pressure range. With specific regard to process details, concerns often arise with process gases and gas pressures, the degree of plasma uniformity, and the controllability of the particle composition within the plasma, i.e., the plasma. In response to the development of the electronic industry, a plasma source capable of exciting a large-area, high-density, uniform plasma at a low pressure is currently the main research direction.

In the conventional semiconductor manufacturing industry, various types of plasma apparatuses are widely used for various processes. Surface Wave Plasma (SWP) is a new type of plasma generation technology developed in recent years, and compared with Capacitive Coupling Plasma (CCP), inductive Coupling Plasma (ICP), electron cyclotron resonance plasma (ECR) and other types, it is simpler in structure, lower in cost, capable of generating plasma of higher density, and has a considerable advantage in large area homogenization of plasma.

At present, there are many excitation methods for large area surface wave plasma, including circular tube inner wall surface wave, slot antenna surface wave, radial slot antenna surface wave (RSLA), etc. Among them, the commercial ones are mainly the surface waves of the inner wall of the circular tube and the surface waves of the radial slot antenna. The size of the antenna structure of the slot antenna surface wave is usually limited to the size of the waveguide, and meanwhile, when the surface wave is transmitted from the lower part of the slot to the periphery, attenuation inevitably occurs, so that the generated plasma is unevenly distributed. Therefore, the slot antenna surface wave type plasma source is mainly applied to plasma laboratories for qualitative research and is not applied to large-area plasma application.

SUMMERY OF THE UTILITY MODEL

Therefore, the utility model provides a microwave resonant cavity, compare in prior art and set up the surface wave plasma resonant cavity on single waveguide with the slit antenna, feed microwave energy into the vacuum cavity evenly from the whole medium window place face through opening a plurality of slits on the resonant cavity bottom wall of central symmetry structure to make the vacuum cavity produce the even surface wave plasma of large tracts of land; meanwhile, compared with the existing circular tube inner wall surface wave excitation mode and the radial slotted antenna surface wave excitation mode, the slit can ensure the stability of feeding microwave energy into the vacuum cavity so as to excite and form plasma.

The utility model discloses a microwave plasma resonant cavity is realized through following technical scheme:

a microwave resonant cavity, comprising: the device comprises a resonant cavity, a waveguide input port, a medium window, a vacuum cavity, a deposition table, an adjustable center adjusting table, a gas inlet and a gas outlet, wherein the waveguide input port is arranged in the middle of the top of the resonant cavity and communicated with the resonant cavity, the medium window and the vacuum cavity are arranged below the bottom wall of the resonant cavity, the deposition table is arranged on the bottom wall of the vacuum cavity, the adjustable center adjusting table is arranged below the deposition table, and the gas inlet and the gas outlet are arranged on two side walls of the vacuum cavity;

the resonant cavity is a centrosymmetric structure formed by splicing multiple sections of waveguides, the symmetric center of the resonant cavity is superposed with the projection of the center of the dielectric window in the vertical direction, the bottom wall of the resonant cavity is provided with a plurality of slits, and the slits can uniformly feed microwave energy into the vacuum cavity through the dielectric window.

Preferably, the waveguide input port is cylindrical and is fixedly and hermetically connected with the resonant cavity.

Preferably, the adjustable centering table is movable in a vertical direction for optimal adjustment of the state of the plasma formed by excitation.

Preferably, the resonant cavity is a cross-shaped structure formed by two rectangular waveguides in an orthogonal manner, the four branches of the cross-shaped structure are identical in shape and size, and the joints of the four branches adopt circular arc transition.

Preferably, the bottom wall of each branch of the resonant cavity is provided with more than two slits, the slits on each branch are parallel to each other and arranged to form an array, and the length direction of the slit is perpendicular to the length direction of the waveguide where the slit is located.

Preferably, said arrays on opposite said branches are symmetrical with respect to the centre of said resonant cavity.

Preferably, the length of each segment of the waveguide is greater than or equal to the diameter of the dielectric window.

Preferably, the bottom wall of each branch of the resonant cavity is provided with four slits, and the four slits on each branch are arranged to form a rectangular frame.

Preferably, the rectangular frames on the two opposite branches are symmetrical with respect to the center of the resonant cavity.

Preferably, the long side and the short side of the rectangular frame on each branch are respectively parallel to the long side and the short side of the waveguide of the rectangle in which the branch is located;

the long side and the short side of the rectangular frame on each branch form included angles with the long side and the short side of the waveguide of the rectangle in which the long side and the short side are located.

The utility model discloses following beneficial effect has:

(1) By arranging the resonant cavity with a centrosymmetric structure and arranging a plurality of slits on the bottom wall of the resonant cavity, microwave energy can be uniformly fed into the vacuum cavity through the surface of the dielectric window, so that large-area uniform surface wave plasma is generated in the vacuum cavity; at the same time, the slits ensure stability in feeding microwave energy into the vacuum chamber to initiate plasma formation.

(2) The adjustable central deposition table which can move in the vertical direction is arranged, and the state of the plasma can be optimally adjusted, so that the uniformity of the deposited film is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following descriptions are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a plan view of a microwave resonant cavity according to a first embodiment of the present invention;

fig. 2 is a top view structural diagram of a microwave resonant cavity according to a first embodiment of the present invention;

fig. 3 is a top view structural diagram of a microwave resonant cavity according to a second embodiment of the present invention;

1-a microwave input port; 2-a resonant cavity; 3-vacuum chamber; 4-a dielectric window; 5-a slit; 6-gas inlet; 7-a gas outlet; 8-a deposition station; 9-adjustable center adjusting table.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood as a specific case by those skilled in the art.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

Referring to fig. 1, the present embodiment discloses a microwave resonant cavity, which includes a resonant cavity 2, a microwave input port 1 is disposed at a middle position of a top end of the resonant cavity 2, and is used for inputting microwave energy; the microwave oven comprises a resonant cavity 2, a dielectric window 4 and a vacuum cavity 5, wherein the resonant cavity 2 is of a central symmetrical structure formed by splicing multiple sections of waveguides, the symmetrical center of the resonant cavity is superposed with the projection of the center of the dielectric window in the vertical direction, a plurality of slits 5 are formed in the bottom wall of the resonant cavity 2, and the slits 5 can uniformly feed microwave energy into the vacuum cavity 3 through the dielectric window 5.

The plasma resonant cavity is arranged by arranging a central symmetrical structure, and a plurality of slits 5 are arranged on the bottom wall of the resonant cavity 2, compared with the surface wave plasma resonant cavity in which a slit antenna is arranged on a single waveguide in the prior art, the utility model discloses a surface of a dielectric window 4 can be used for uniformly feeding microwave energy into a vacuum cavity 3 through the plurality of slits 5 arranged on the bottom wall of the resonant cavity 2, so that large-area uniform surface wave plasma is generated in the vacuum cavity 3, and further the treatment of large-area wafers is satisfied; meanwhile, compared with the existing circular tube inner wall surface wave excitation mode and the radial slotted antenna surface wave excitation mode, the slit 5 can ensure the stability of feeding microwave energy into the vacuum cavity 3 so as to excite and form plasma.

Preferably, referring to fig. 2, the resonator 2 is a cross-shaped structure formed by two orthogonal sections of rectangular waveguides 21, and the four branches 22 of the cross-shaped structure are identical in shape and size. By the arrangement, the resonant cavity 2 can be uniformly distributed over the dielectric window 4 in a large area, so that a foundation is laid for the uniform and large-area distribution of the slit 5 on the dielectric window 4, the microwave energy fed into the vacuum cavity 3 through the slit 5 and the dielectric window 4 is more uniform, the large-area microwave energy can be fed in, and finally large-area uniform surface wave plasma is generated in the vacuum cavity 3, so that the large-area wafer treatment is met. Further, in order to further improve the uniformity and stability of the microwave mode transition, circular arc transition is adopted at the right-angle connection positions of the four waveguide branches.

Wherein the length of each waveguide section 21 is larger than or equal to the diameter of the dielectric window 4. The length of each waveguide section 21 can be adjusted according to the size of the required plasma, wherein the size of the plasma is approximately equal to the diameter of the dielectric window 4 below the waveguide 21, and in order to ensure the uniformity of the plasma in the vacuum chamber 3, a plurality of slits 5 need to be uniformly arranged on the waveguide 21 so as to ensure that the microwave energy feeding area in the radial direction of the dielectric window 4 is as large as possible.

In this embodiment, four slits 5 are disposed on the bottom wall of each branch 22 of the resonant cavity 2, and the four slits 5 on each branch 22 are arranged to form a rectangular frame. When the microwave is fed through the input port, a corresponding wall current distribution is formed on the inner wall of the rectangular waveguide 21. The working principle of the slit 5 is to cut off the wall current of the waveguide 21 and make it pass through in the form of displacement current, so as to form an electric field pointing to the outside of the waveguide 21 through the slit 5, and feed microwave energy into the vacuum chamber 3 to form plasma. A dielectric window 4 made of quartz is generally used below the slit 5, and the dielectric window 4 provides a dielectric boundary condition required for the surface wave plasma while maintaining the vacuum chamber 3 in a vacuum state. When the microwave energy is enough and the gas condition in the vacuum cavity 3 is satisfied, plasma glow can occur, and when the plasma density is higher than the surface wave plasma critical density, surface waves can be formed on the interface between the dielectric window 4 and the plasma, thereby maintaining high-density plasma discharge.

Because each branch 22 of the resonant cavity 2 is provided with a plurality of slits 5 arranged in a rectangular frame, each slit 5 arranged in a rectangular frame on each branch 22 can be equivalent to one surface wave source, so that four surface wave sources are uniformly distributed on the dielectric window 4, the surface wave sources can uniformly feed microwave energy into the vacuum cavity 3 from the surface of the whole dielectric window 4, and surface wave plasma with large area and uniform distribution is generated in the vacuum cavity 3.

In addition, the shape and size of the slit 5 and the position of the slit on the waveguide 21 are determined by the frequency of the microwave generated by the microwave source of the generating device and the type of the waveguide 21. For example: the microwave source generates microwave with frequency of 2.45GHz, and rectangular waveguide 31 of BJ-22 type can be used, accordingly, the size of single slit 5 needs to be adjusted according to the size of waveguide 21, as mentioned above, the purpose of slit 5 is to cut off the surface current of the inner wall of waveguide 21 as much as possible, and rectangular slit 5 with size of 61 × 10mm can be selected corresponding to BJ-22 waveguide 31. The setting position of the slit 5 on the waveguide 21 can be adjusted using a tuner with the aim of cutting off the current on the inner wall surface of the waveguide 21 as much as possible.

In this embodiment, the adjustable center adjusting stage 9 can move up and down along the vertical direction, so that the plasma state can be optimally adjusted, and the uniformity of the deposited film can be improved.

Example 2

The present embodiment provides a microwave resonant cavity, which is different from embodiment 1 in that more than two slits 5, specifically four slits 5, are disposed on the bottom wall of each branch 22 of the resonant cavity 2, and the slits 5 on each branch 22 are parallel to each other and arranged to form an array, and the length direction of the slit 5 is perpendicular to the length direction of the waveguide 21 where the slit is located.

By the arrangement, more microwave energy can be fed into the vacuum cavity through the slit 5 arranged on the bottom wall of the resonant cavity 2, so that the feeding efficiency of the microwave energy is improved, and simultaneously, large-area uniform feeding of the microwave energy is realized.

In this embodiment, the arrays on the two opposite branches 22 are symmetrical with respect to the center of the cavity 3. The arrangement is favorable for uniform distribution of plasmas formed by excitation in the vacuum cavity.

The other structural arrangements of the microwave resonant cavity in this embodiment are the same as those in embodiment 1, and are not described herein again.

All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, and these are all within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A microwave resonant cavity, comprising: the device comprises a resonant cavity, a waveguide input port, a medium window, a vacuum cavity, a deposition table, an adjustable center adjusting table, a gas inlet and a gas outlet, wherein the waveguide input port is arranged in the middle of the top of the resonant cavity and communicated with the resonant cavity, the medium window and the vacuum cavity are arranged below the bottom wall of the resonant cavity, the deposition table is arranged on the bottom wall of the vacuum cavity, the adjustable center adjusting table is arranged below the deposition table, and the gas inlet and the gas outlet are respectively arranged on two side walls of the vacuum cavity;

2. A microwave resonant cavity as recited in claim 1, wherein the waveguide input port is cylindrical and is sealingly connected to the cavity.

3. A microwave resonant cavity according to claim 1, wherein the adjustable centering stage is vertically movable for optimal adjustment of the state of the excited plasma.

4. A microwave resonant cavity according to claim 1, wherein the resonant cavity is a cross-shaped structure formed by two rectangular waveguides orthogonal to each other, four branches of the cross-shaped structure have the same shape and size, and the joints of the four branches are in circular arc transition.

5. A microwave resonant cavity according to claim 4, wherein four of the slots are provided in the bottom wall of each of the branches of the resonant cavity, the four slots in each of the branches being arranged to form a rectangular frame.

6. A microwave resonant cavity according to claim 5, wherein the rectangular frames on opposing branches are symmetrical about the center of the cavity.

7. A microwave resonant cavity according to claim 6, wherein the long and short sides of the rectangular frame on each of the branches are parallel to the long and short sides, respectively, of the waveguide of the rectangle in which it is located;

8. A microwave resonant cavity according to claim 4, wherein the bottom wall of each of the branches of the resonant cavity is provided with more than two slits, the slits of each of the branches are parallel to each other and arranged to form an array, and the length direction of the slits is perpendicular to the length direction of the waveguide in which the slits are located.

9. A microwave resonant cavity according to claim 5, wherein the arrays on opposite ones of the branches are symmetrical about a centre of the cavity.

10. A microwave resonant cavity according to claim 6, wherein each segment of the waveguide has a length greater than or equal to the diameter of the dielectric window.