阅读说明：本技术 表面波等离子体装置 (Surface wave plasma device ) 是由 王桂滨 韦刚 于 2018-07-27 设计创作，主要内容包括：本发明提供一种表面波等离子体装置,包括谐振板,在谐振板的远离反应腔室的一个表面上形成有凹槽,该凹槽中可分离的填充有介质结构,用于调节反应腔室中的等离子体分布均匀性。本发明提供的表面波等离子体装置,其不仅可以提高调节等离子体分布均匀性的便捷性、灵活性,而且还可以避免腔室颗粒增加、谐振板下表面不平整的问题。(The invention provides a surface wave plasma device, which comprises a resonance plate, wherein a groove is formed on one surface of the resonance plate far away from a reaction chamber, and a medium structure is detachably filled in the groove and is used for adjusting the distribution uniformity of plasma in the reaction chamber. The surface wave plasma device provided by the invention can improve the convenience and flexibility of adjusting the distribution uniformity of the plasma, and can avoid the problems of increase of cavity particles and unevenness of the lower surface of the resonance plate.)

1. A surface wave plasma device is characterized by comprising a resonance plate, wherein a groove is formed on one surface of the resonance plate far away from a reaction chamber, and a dielectric structure is detachably filled in the groove and used for adjusting the distribution uniformity of plasma in the reaction chamber.

2. A surface wave plasma device as defined in claim 1 wherein said recess is at least one in number and is formed circumferentially around said resonator plate as an annular recess, said recess being rectangular in longitudinal cross section.

3. A surface wave plasma apparatus as defined in claim 1 wherein said dielectric structure includes at least one dielectric element, different ones of said dielectric elements being made of different dielectric materials.

4. A surface wave plasma apparatus as set forth in claim 3 wherein said dielectric structure comprises a plurality of dielectric elements each having a circular cross-sectional shape, said plurality of dielectric elements being stacked in series along a depth direction of said recess.

5. A surface wave plasma device as defined in claim 3 wherein said dielectric structure comprises a dielectric element, said dielectric element being a toroidally-shaped dielectric plate.

6. A surface wave plasma device as recited in claim 3, wherein said dielectric structure comprises two dielectric elements, said dielectric elements being arranged alternately to form a toroidally-shaped dielectric slab.

7. A surface wave plasma device as defined in claim 2 wherein said recess is plural in number, and a plurality of said recesses are provided at intervals in a radial direction of said resonator plate.

8. A surface wave plasma device as defined in claim 2 wherein one-half of the inner diameter of said recess is greater than one wavelength of microwaves in said resonator plate; the radial width of the groove is smaller than one wavelength of the microwave in the resonance plate; the depth of the grooves is an integral multiple of a half wavelength or a quarter wavelength of microwaves in the resonator plate.

9. A surface wave plasma device as defined in claim 8 wherein one-half of the inner diameter of said recess ranges from 30mm to 150 mm; the radial width of the groove ranges from 20mm to 100 mm.

10. A surface wave plasma device as defined in claim 9 wherein said recess has a depth in the range of 10mm to 40 mm.

Technical Field

The invention relates to the technical field of microelectronics, in particular to a surface wave plasma device.

Background

Plasma processing equipment is now widely used in the fabrication of integrated circuits or MEMS devices. The plasma processing apparatus includes a capacitively coupled plasma processing apparatus, an inductively coupled plasma processing apparatus, an electron cyclotron resonance plasma processing apparatus, a surface wave plasma device, and the like. Among them, the surface wave plasma device is one of the most advanced plasma processing apparatuses because it can obtain a higher plasma density and a lower electron temperature than other plasma processing apparatuses and does not require an external magnetic field to be increased.

The existing surface wave plasma device mainly comprises a microwave source mechanism, a reaction chamber and a resonant cavity arranged at the top of the reaction chamber, wherein the resonant cavity comprises a metal cavity with a top wall and a side wall, a slot plate arranged on the inner side of the side wall of the metal cavity, and a resonant plate arranged below the slot plate, and the lower surface of the resonant plate is exposed in the reaction chamber. When the process is carried out, the microwave source mechanism is used for providing microwave energy and feeding the microwave energy into the resonant cavity through the feeding coaxial probe; the slit plate is used for coupling microwaves into the reaction chamber; the resonant plate is used for enabling the microwaves coupled from the slot plate to generate total reflection on the lower surface of the resonant plate so as to form surface wave plasma.

In order to adjust the distribution uniformity of the plasma formed in the reaction chamber, the conventional surface wave plasma device is realized by setting different slit arrangements and slit numbers on the slit plates, but the types of the process gases applicable to the adjustment mode are limited, which means that more different types of slit plates are needed as spare parts to adapt to the frequent adjustment of the types of the process gases, thereby increasing the maintenance difficulty of the equipment and increasing the equipment and labor cost. Meanwhile, the process of replacing the gap plate is complex, and the adjustment convenience is poor.

Disclosure of Invention

The invention aims to at least solve one of the technical problems in the prior art, and provides a surface wave plasma device which not only can improve the convenience and flexibility of adjusting the distribution uniformity of plasma, but also can avoid the problems of increased cavity particles and uneven lower surface of a resonance plate.

The surface wave plasma device comprises a resonant plate, wherein a groove is formed on one surface of the resonant plate far away from a reaction chamber, and the groove is detachably filled with a medium structure for adjusting the distribution uniformity of plasma in the reaction chamber.

Optionally, the number of the grooves is at least one, and an annular groove is formed around the circumference of the resonance plate, and the longitudinal section of the groove is rectangular.

Optionally, the media structure comprises at least one media element, and different types of the media elements are made of different types of media materials.

Optionally, the medium structure includes a plurality of medium units, each of the medium units has a circular cross-sectional shape, and the plurality of medium units are sequentially stacked in the depth direction of the groove.

Optionally, the dielectric structure includes a dielectric element, and the dielectric element is a circular ring-shaped dielectric slab.

Optionally, the dielectric structure includes two kinds of dielectric units, and the two kinds of dielectric units are alternately arranged to form a circular ring-shaped dielectric slab.

Optionally, the number of the grooves is multiple, and the grooves are arranged at intervals along the radial direction of the resonator plate.

Optionally, one half of the inner diameter of the groove is larger than one wavelength of the microwave in the resonance plate; the radial width of the groove is smaller than one wavelength of the microwave in the resonance plate; the depth of the grooves is an integral multiple of a half wavelength or a quarter wavelength of microwaves in the resonator plate.

Optionally, a value of one half of the inner diameter of the groove ranges from 30mm to 150 mm; the radial width of the groove ranges from 20mm to 100 mm.

Optionally, the depth of the groove ranges from 10mm to 40 mm.

The invention has the following beneficial effects:

the surface wave plasma device provided by the invention has the advantages that the grooves are formed on one surface of the resonance plate, which is far away from the reaction chamber, and the grooves are filled with the medium structures in a separable mode, so that the plasma density in the region, corresponding to the grooves, in the reaction chamber can be adjusted, and the plasma distribution uniformity in the reaction chamber can be adjusted by setting parameters such as the shape, the size (such as radial width, depth, inner diameter and the like), the number, the position and the arrangement mode of the grooves and/or setting the material type, the number, the size and the arrangement mode of the medium structures, so that the application range of the process gas type can be expanded, and the flexibility of adjusting the plasma distribution uniformity can be improved.

Meanwhile, the groove is formed on one surface of the resonance plate far away from the reaction chamber, so that the problems of chamber particle increase and uneven lower surface of the resonance plate caused by the fact that the groove is exposed in the reaction chamber can be avoided, and the medium structure can be allowed to be detachably filled in the groove, so that the medium structure can be replaced more conveniently without unloading the resonance plate, and convenience in adjusting the distribution uniformity of the plasma can be improved.

Drawings

Fig. 1 is a sectional view of a surface wave plasma device according to a first embodiment of the present invention;

fig. 2 is a plan view of a resonator plate used in the first embodiment of the present invention;

fig. 3 is a top view of a resonator plate used in a second embodiment of the present invention;

fig. 4 is a top view of a resonator plate used in a third embodiment of the present invention;

fig. 5 is a plan view of a resonator plate used in a fourth embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the surface wave plasma device provided by the present invention will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1 and 2 together, a surface wave plasma device according to a first embodiment of the present invention includes a microwave source system 1 for providing microwaves, a waveguide 2 for transmitting the microwaves, a coaxial probe 3, a reaction chamber 6, and a resonant cavity 4 disposed at the top of the reaction chamber 6, wherein the coaxial probe 3 is used for feeding the microwaves into the resonant cavity 4.

The resonator 4 includes a metal cavity having a top wall 41 and a side wall 42, a slit plate 5 disposed inside the side wall 42 of the metal cavity, and a resonator plate 7 disposed below the slit plate 5, wherein the metal cavity is typically made of a metal such as stainless steel. The slit plate 5 is generally made of metal such as aluminum or copper. The thickness of the slit plate 5 is usually in the range of 0.5mm to 6 mm. And, a plurality of slits 51 for coupling the electromagnetic wave in the resonant cavity 4 into the reaction chamber 6 below are provided in the slit plate 5. The orthographic projection shape of each gap 51 on the plane of the gap plate 5 is similar to an L shape, namely, the gap is composed of two mutually perpendicular gaps, and the width of each gap 51 ranges from 1mm to 6 mm; the length of the slit 51 ranges from 10mm to 35 mm. The plurality of slits 51 surround the resonant cavity 4 for at least one circle in the circumferential direction, and the number of circles can be adjusted according to the diameter of the actual resonant cavity 4, and is usually between 1 and 6 circles. And, the number of slits 51 in the slit ring closer to the edge of the slit plate 5 is larger. For example, the plurality of slots 51 are wound two times in the circumferential direction of the resonant cavity 4, wherein the number of slots in the inner ring is 8 and the number of slots in the outer ring is 16. By changing the number of turns of the slits 51 and the number of slits in the same turn, the distribution of the electromagnetic wave coupled under the slit plate 5 can be adjusted, and thus the plasma distribution uniformity in the reaction chamber 6 can be adjusted.

The resonator plate 7 is made of a high dielectric constant material such as ceramic or quartz, and the main function of the resonator plate 7 is to cause the electromagnetic wave coupled from the upper slit plate 5 to be totally reflected on the lower surface of the resonator plate 7, thereby forming surface wave plasma. Also, one surface of the resonance plate 7 close to the reaction chamber 6 (i.e., the lower surface of the resonance plate 7 in fig. 1) is exposed in the reaction chamber 6, and a groove 71 is formed on one surface of the resonance plate 7 remote from the reaction chamber 6 (i.e., the upper surface of the resonance plate 7 in fig. 1). And, a dielectric structure 8 is detachably filled in the groove 71 for adjusting the plasma distribution uniformity in the reaction chamber 6.

The separable filling means that the dielectric structure 8 filled in the groove 71 can be taken out, so that the dielectric structure 8 can be flexibly and conveniently replaced without replacing the resonance plate 7, the adjustment convenience is improved, the frequent adjustment of the process gas type can be adapted, the maintenance difficulty of the equipment is reduced, and the equipment and labor cost are reduced.

In practical application, the shape, size, number, position and arrangement of the grooves 71 can be set differently; and/or, the material type, quantity, size and arrangement mode of the dielectric structure 8 are used for adjusting the plasma distribution uniformity in the reaction chamber, so that the application range of the process gas type can be expanded, and the flexibility of adjusting the plasma distribution uniformity is improved.

Meanwhile, by forming the groove 71 on the surface of the resonator plate 7 away from the reaction chamber 6, the problems of increased chamber particles and uneven lower surface of the resonator plate due to the exposure of the groove 71 in the reaction chamber 6 can be avoided, and the dielectric structure 8 can be allowed to be detachably filled in the groove 71, so that the dielectric structure 8 can be replaced more conveniently without unloading the resonator plate 7, and the convenience of adjusting the plasma distribution uniformity can be improved.

In the present embodiment, as shown in fig. 2, the groove 71 is an annular groove that surrounds in the circumferential direction of the reaction chamber 6, and the longitudinal section of the annular groove is rectangular. The uniformity of the plasma distribution in the reaction chamber can be adjusted by setting parameters such as the shape, size (e.g., radial width, depth, inner diameter, etc.), number, location, and arrangement of the grooves 71.

One half of the inner diameter of the groove 71 (i.e., the dimension R in fig. 2) is larger than one wavelength of the microwave in the resonator plate 7, and optionally, the value of the dimension R ranges from 30mm to 150 mm. The radial width B of the annular groove is smaller than one wavelength of microwaves in the resonant plate, and optionally, the value range of the radial width B is 20-100 mm. The depth of the groove 71 is an integral multiple of a half wavelength or a quarter wavelength of the microwave in the resonant plate 7, and optionally, the depth of the groove 71 ranges from 10mm to 40 mm.

The dielectric structure 8 comprises at least one dielectric element, the different dielectric elements being made of different dielectric materials. In the present embodiment, the dielectric structure 8 includes a dielectric element, which is a circular ring-shaped dielectric plate. Optionally, the dielectric material used for the dielectric unit includes quartz, ceramic, or teflon, etc.

Referring to fig. 3, a surface wave plasma device according to a second embodiment of the present invention is different from the first embodiment only in that: the structures and the number of the dielectric structures filled in the grooves 71 are different.

Specifically, in the present embodiment, the groove 71 is an annular groove that surrounds in the circumferential direction of the reaction chamber 6. And the medium structure comprises a plurality of medium units which are alternately arranged to form a circular ring-shaped medium plate. For example, as shown in fig. 3, the number of the dielectric units is two, namely, a first dielectric unit 8a and a second dielectric unit 8b, which are the same in number and are alternately arranged to form a circular ring-shaped dielectric slab. The dielectric material used for the first dielectric unit 8a and the second dielectric unit 8b may be quartz, ceramic, teflon, or the like. By setting the material types, the number and the arrangement of the first dielectric unit 8a and the second dielectric unit 8b, the electric field distribution generated in the circumferential region of the lower surface of the resonance plate 7 corresponding to the annular groove can be changed, so that the plasma distribution uniformity in the circumferential region corresponding to the annular groove can be adjusted.

Referring to fig. 4, a surface wave plasma device according to a third embodiment of the present invention is different from the first and second embodiments only in that: the structures and the number of the dielectric structures filled in the grooves 71 are different.

Specifically, in the present embodiment, the groove 71 is an annular groove that surrounds in the circumferential direction of the reaction chamber 6. Moreover, the medium structure comprises a plurality of medium units, the cross section of each medium unit is in a circular ring shape, and the plurality of medium units are sequentially overlapped along the depth direction of the groove 71. For example, as shown in fig. 4, the media units are three types, i.e., a first media unit 8a, a second media unit 8b, and a third media unit 8c, which are stacked in order in the vertical direction. The dielectric materials adopted by the first dielectric unit 8a, the second dielectric unit 8b and the third dielectric unit 8c can be quartz, ceramic, polytetrafluoroethylene or the like, and the respective thicknesses range from 5mm to 20 mm.

By changing the material types and thicknesses of the first dielectric unit 8a, the second dielectric unit 8b and the third dielectric unit 8c to form different forms of dielectric filling combinations, the electric field distribution below the resonant plate 7 can be adjusted in a wider range, and the plasma uniformity can be adjusted.

Referring to fig. 5, a fourth embodiment of the surface wave plasma device of the present invention is an improvement of the first embodiment.

Specifically, the grooves are multiple, and the multiple grooves are arranged at intervals along the radial direction of the resonance plate. In the present embodiment, each groove is an annular groove that surrounds along the circumferential direction of the reaction chamber 6, and different annular grooves have different inner diameters and are nested with each other. For example, as shown in fig. 5, there are three annular grooves, and the radial width and depth of the three annular grooves are uniform, and the intervals between two adjacent annular grooves are equal. Optionally, the radial width and depth of each annular groove are both 5mm to 20 mm. One half of the inner diameter of the annular groove with the smallest inner diameter is larger than one wavelength of microwaves in the resonance plate 7, and the value range of the size is 30-150 mm. By changing the radial radius, depth, number and interval of the annular grooves and the type of the filling material, the electric field distribution below the resonance plate 7 can be more effectively adjusted, and then the plasma uniformity can be adjusted.

It should be noted that in this embodiment, the dielectric structure is the same as that in the first embodiment described above for each annular groove, but the present invention is not limited to this, and in practical applications, the dielectric structure may also be the same as that in the second to third embodiments described above for each annular groove.

In summary, the surface wave plasma device provided by the present invention can adjust the plasma density in the region corresponding to the groove in the reaction chamber by forming the groove on the surface of the resonance plate away from the reaction chamber and detachably filling at least one dielectric structure in the groove, and can adjust the plasma distribution uniformity in the reaction chamber by setting the parameters of the shape, size (such as radial width, depth, inner diameter, etc.), number, position, arrangement, etc. of the groove and/or setting the material type, number, size, arrangement of the dielectric structure, thereby expanding the applicable range of the process gas type and improving the flexibility of adjusting the plasma distribution uniformity.

Meanwhile, the groove is formed on one surface of the resonance plate far away from the reaction chamber, so that the problems of chamber particle increase and uneven lower surface of the resonance plate caused by the fact that the groove is exposed in the reaction chamber can be avoided, and the medium structure can be allowed to be detachably filled in the groove, so that the medium structure can be replaced more conveniently without unloading the resonance plate, and convenience in adjusting the distribution uniformity of the plasma can be improved.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.