TW201528883A - Plasma processing apparatus - Google Patents

Abstract

A plasma processing apparatus comprises a reaction chamber; the reaction chamber comprises a base; the base is provided with an electrostatic chuck; the substrate is mounted on the electrostatic chuck; an adjusting ring surrounds the electrostatic chuck, the adjusting ring comprising a stationary ring and a mobile ring fixed above the stationary ring; the stationary ring surrounds the electrostatic chuck or the base; the stationary ring comprises a support surface; the support surface includes a recess; the mobile ring comprises a first portion closely attached to the electrostatic chuck and is located below the substrate; the first portion has an upper surface having a first height; a second portion having an upper surface with a second height is disposed at the peripheral portion of the first portion; the second portion has a lower surface that includes a protrusion matching with the recess position; a drive device drives the second portion to move vertically between a first position and a second position, and when it is moved to the second position, the lower end of the protrusion is still in the recess.

Description

Plasma processing device

The present invention relates to the field of semiconductor manufacturing technology, and in particular, to an adjustment ring applied to a plasma processing apparatus.

Semiconductor processing processes for the fabrication of integrated circuits include chemical vapor deposition processes, plasma etching processes, etc. Typical etching of tantalum or insulating material tantalum oxide requires the use of plasma etching equipment. As shown in the plasma etching apparatus of FIG. 1, the plasma etching apparatus includes a reaction chamber 100, and the bottom of the reaction chamber includes a base 22 to which an RF power source is connected. An electrostatic chuck 21 is disposed on the susceptor for fixing the substrate 20 to be processed placed above the electrostatic chuck. The periphery of the electrostatic chuck also includes a uniformity adjustment ring that improves the uniformity of processing relative to the neutral region of the edge region of the substrate 20 by designing the material, shape, and even thickness of the adjustment ring. The top of the reaction chamber opposite the substrate includes a gas distribution device such as a gas showerhead 11 that is coupled to an external source 110. The design of the adjustment ring in plasma etching plays a very important role in the processing effect of the substrate. For example, the selection of the adjustment ring material is different, especially the difference in the conductivity characteristics causes the RF power fed into the susceptor 22 to be distributed to the central area of the substrate. The ratio of the edge region is different, and the distribution of the plasma is different. The size of the gap between the lower surface of the edge of the substrate 20 and the innermost side of the adjustment ring 10 can affect the amount of polymer deposition in the back region of the edge of the substrate, and also affect the basis. The temperature distribution in the edge region of the sheet 20 also indirectly affects the plasma treatment effect; the thickness of the adjustment ring, especially the height of the upper surface, greatly affects the flow direction of the reaction gas, such as the reaction gas when the upper surface of the adjustment ring 10 is higher than the height of the substrate to be processed. Dispersing along the surface of the substrate to the periphery, when the advection gas encounters the adjustment ring, the air flow will be lifted by the raised adjustment ring, and if the adjustment ring is lower, the air flow will also decrease. These different conditions will cause different gas distribution on the surface of the substrate. . Therefore, the design of the adjusting ring 10 comprehensively affects various factors such as plasma concentration distribution, temperature distribution, and airflow distribution in the plasma processing.

In the existing plasma processing chamber, the adjusting ring 10 is corroded by the reaction gas flowing into the reaction chamber, so that the upper surface of the adjusting ring 20 exposed to the upper plasma gradually becomes lower as time passes, which causes the above. The plasma concentration distribution, temperature distribution, airflow distribution and other factors will also change slowly with time. The changes of these factors will cause the plasma treatment effect to shift with time. After a long time debugging, the processing parameters will be processed at intervals. The effect will gradually deteriorate. To completely restore the original state, it is necessary to replace the original shape of the adjustment ring, but this is not only costly, but also requires complicated verification and debugging steps each time the parts are replaced to ensure that the indicators in the reaction chamber are replaced after replacing the new parts. The same before the replacement, the time cost is also very large. In order to solve this problem, a conventionally adjustable lifting ring is used in the prior art KR20080023569. When the upper surface of the adjusting ring needs to be raised, the driving mechanism raises the position of the adjusting ring to match different processing parameters. However, this method inevitably brings many problems: when it is raised to a higher position, a wide gap is formed between the bottom surface of the adjusting ring and the upper surface of the lower part, and the gap height is often greater than 1 mm due to the adjustment of the amplitude. Therefore, the plasma at the edge of the substrate can enter the gap along the gap, or the reactive gas flows into the gap and is ignited by the RF electric field to form a plasma. The plasma formed at the bottom not only corrodes surrounding components but also forms pollutants. Particles affect the treatment effect. At the same time, during the gradual lifting of the adjusting ring, when the bottom surface of the adjusting ring is separated from the lower contact surface, an arcing occurs due to a sharp change of the electric field distribution, which not only loses parts but also seriously affects the processing effect of the substrate and needs to be avoided.

Therefore, the industry needs a new design that can flexibly set the parameters of the adjustment ring and prevent the plasma from flowing into the gap of the adjustment ring, and also prevent the new adjustment ring from being generated by the discharge phenomenon.

The problem to be solved by the present invention is to provide a plasma processing apparatus capable of compensating for the offset of the plasma treatment effect caused by the loss of the adjustment ring, while preventing the occurrence of gaps and discharge phenomena between the plasma entering components. In order to solve the above problems, the inventors provide a plasma processing apparatus, comprising: a reaction chamber, the reaction chamber includes a base, and the base is provided with an electrostatic chuck, and the substrate to be processed is disposed on the electrostatic chuck An adjustment ring surrounds the periphery of the electrostatic chuck, wherein the adjustment ring includes a fixing ring and a moving ring above the fixing ring, wherein: the fixing ring surrounds the electrostatic chuck or the base, and the fixing ring The surface includes a support surface, the support surface includes a groove, and a bottom surface of the moving ring matches a support surface of the fixing ring, the moving ring includes a surface that is close to the electrostatic chuck and located below the edge of the substrate to be processed a portion, the first portion has an upper surface of a first height, a second portion having a second upper surface is located at a periphery of the first portion, and a lower portion of the second portion of the moving ring includes a protrusion and a lower fixing ring The upper groove positions are matched, and a driving device drives the second portion of the moving ring to move up and down between the lower first position and the higher second position, wherein When the lower end of the movable projecting portion to the second position is still located in the groove. There is a gap between the lower surface of the moving ring and the support surface of the fixed ring when the moving ring moves to the second position.

Wherein the protruding portion and the groove of the moving ring have vertical side walls, and the distance between the side wall of the protruding portion and the inner side wall of the groove when moving to the second position is less than 1 mm, which can ensure that the plasma does not leak during the lifting process. It is also possible to prevent the sudden change in the potential of the moving ring from generating a discharge.

The first portion and the second portion of the moving ring can be raised and lowered simultaneously, wherein the first portion can also be fixed to the lower fixing ring such that the first portion has a stable spacing from the lower surface of the substrate.

A transition portion is further included between the first portion and the second portion, the upper surface of the transition portion gradually varying between the first height and the second height.

The adjustment ring is made of quartz or tantalum carbide or alumina to effect adjustment of the electric field distribution.

The drive means includes a drive rod connected to the moving ring through the retaining ring, the lower end of the drive rod being coupled to a motor or cylinder for controllable movement of the drive rod up and down.

The present invention also provides a method of operating the plasma processing apparatus, wherein after the plasma treatment of the substrate to be processed is completed a plurality of times, the driving device drives the second portion of the moving ring to rise, so that The upper surface of the second portion of the moving ring has a fixed height difference relative to the surface of the substrate. This will ensure long-term stability of the plasma treatment effect.

Please refer to FIG. 2a, 2b for understanding the solution of the present invention. FIG. 2a is an enlarged structural view of A in FIG. 1. The adjusting ring 10 of the present invention comprises a first fixing ring 102 at the bottom and a surrounding of the first fixing ring 102. The second fixing ring 103. Also included is a top movable ring 101 exposed to the plasma within the reaction chamber, the movable ring surrounding a side wall surrounding the electrostatic chuck or base, the movable ring including the first portion adjacent the electrostatic chuck having a smaller first The thickness ensures that there is sufficient clearance between the lower surface of the substrate 20 and the upper surface of the moving ring. The movable ring 101 has a second portion having a larger second thickness away from the electrostatic chuck, the upper surface of which is directly exposed to the upper plasma. The movable ring further includes a transition portion between the ends adjacent to and away from the electrostatic chuck, the thickness of which gradually increases outwardly between the first thickness and the second thickness. The first fixing ring 102 further includes a card slot, and a protruding portion 104 extends from the lower surface of the upper movable ring to protrude into the card slot. The movable ring is fixed to a driving device 105 which can drive the movable ring to move up and down, and Fig. 2a is a sectional view of the movable ring at the lowest position. As shown in Fig. 2b, the driving device 105 lifts the bottom surface of the movable ring 101 from the upper surface of the lower fixing ring 102, 103, but the protruding portion 104 still has a portion in the groove, the side wall of the protruding portion and the inner wall of the groove Contact or snug to ensure that no plasma leaks into the space created by the lifting of the moving ring. The inner side of the first part is closely attached to the side wall of the electrostatic chuck (the spacing is less than 1mm) to ensure that the plasma does not leak. The fact that the projection 104 does not completely disengage from the recess ensures that the 101 and the lower 102 are always in contact so that the potential between the two does not abruptly and does not cause an arcing. The groove in FIG. 2 is a side cross section, and the actual groove is distributed in a circular shape around the entire electrostatic chuck in a plane, or may be a plurality of small grooves which are separated from each other, and these small grooves together constitute the moving ring 11 and The occlusal structure of the present invention between the retaining rings 102.

In some applications, the height of the adjustment ring below the substrate projection is fixed to ensure a stable temperature distribution, so the adjustment ring closest to the electrostatic chuck cannot move synchronously with the drive mechanism. The present invention proposes a second embodiment. As shown in Fig. 2b, the moving ring 101 in the adjusting ring 10 of the present invention is divided into an inner fixed adjusting ring 101a and an outer movable adjusting ring 101b. In the second embodiment, 101b is the same as the structure shown in FIG. 2a when it is at the lowest position, and when the 101b is raised upward, the protruding portion 104 is close to the inner side wall of the electrostatic chuck to abut the outer side wall of the fixing adjustment ring 101a, and these close verticals The width of the side wall causes the plasma entering the gap to collide with the side wall and then extinguish and cannot leak further downward.

The driving device 105 of the present invention can be fixed to the bottom of the moving adjustment ring in addition to the side shown in Figs. 2-3, and the support portion can pass through the hole formed in the lower fixing ring 102 or 103. The drive unit 105 is coupled to a drive motor or a cylinder external to the reaction chamber to correct the position of the movement adjustment ring 101. The plasma processing device of the invention can automatically adjust the height of the movable adjusting ring 101 according to the needs of different processing technologies during operation to achieve an optimal processing effect, and can also be slightly increased according to the degree of deviation of the processing effect after running for a period of time. Move the adjustment ring to compensate for problems caused by corrosion of the top of the adjustment ring.

The adjusting ring 10 of the present invention may be made of a ceramic material such as quartz, tantalum carbide, or aluminum oxide, or other elements or compounds may be mixed in the above materials to adjust the conductive and heat conducting properties thereof, or to improve the firmness of the adjusting ring. The retaining rings 102, 103 and the moving adjustment ring 101 can be selected from the same or similar materials, and different materials do not affect the implementation of the present invention. The retaining rings 102, 103 may be directly fixed to the extension of the base in the circumferential direction (not shown), or may be indirectly located through the other fixed annular members on the outward extension of the base. In the present invention, the fixing rings 102, 103 may also be integrated into one component, or may be separated into more different fixing rings for other purposes, as long as there is a matching vertical groove at the corresponding position of the protruding portion 104 of the moving ring. Purpose of the invention. Other edge rings may be further disposed around the outer periphery of the adjusting ring 10 of the present invention to further adjust the electric field distribution. The inner side walls of the edge rings and the outer side walls of the moving ring 101 are closely adhered to each other to prevent the plasma moving ring from entering the moving ring and below when rising. The gap between the retaining rings. The lower surface of the moving ring may also be provided with a protrusion which is close to the edge ring, and a corresponding groove is also provided on the upper surface of the lower fixing ring 103. Such a double occlusion structure can more effectively prevent the discharge phenomenon from occurring. It can prevent plasma leakage such as the gap between the moving ring and the fixed ring.

In the plasma processing apparatus to which the adjusting ring of the present invention is applied, a plurality of plasma treatments may be performed, and then the height of the moving ring 101 is raised correspondingly according to the speed of the surface loss of the adjusting ring, so that the upper surface of the moving ring is opposed to the electrostatic chuck The substrate has a fixed positional relationship so that the airflow distribution is stable for a long period of time. The adjustment ring of the present invention can maintain the stability of the plasma treatment effect for a long period of time because of the upper surface structure that can be lifted and lowered, without requiring frequent replacement of a new fixed adjustment ring.

Although the present invention has been disclosed above, the present invention is not limited thereto. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be determined by the scope of the claims.

Conventional knowledge
100‧‧‧reaction chamber
10‧‧‧Adjustment ring
110‧‧‧External air source
11‧‧‧ gas sprinkler
20‧‧‧Substrate to be processed
21‧‧‧Electrical chuck
22‧‧‧Bases the invention
10‧‧‧Adjustment ring
101‧‧‧ movable ring
101a‧‧‧Fixed adjustment ring
101b‧‧‧ movable adjustment ring
102‧‧‧First fixed ring
103‧‧‧second fixed ring
104‧‧‧Protruding
105‧‧‧ drive
20‧‧‧ substrates

1 is a schematic structural view of a conventional semiconductor processing apparatus; FIG. 2a is a cross-sectional view of the adjusting ring of the present invention in a first position; FIG. 2b is a cross-sectional view of the adjusting ring of the present invention in a second position; A cross-sectional view of a second embodiment of the adjustment ring.

101‧‧‧ movable ring

102‧‧‧First fixed ring

103‧‧‧second fixed ring

104‧‧‧Protruding

105‧‧‧ drive

20‧‧‧ substrates

Claims (9)

A plasma processing apparatus comprising: a reaction chamber, the reaction chamber includes a base, the base is provided with an electrostatic chuck, and the substrate to be processed is disposed on the electrostatic chuck; an adjusting ring surrounds the static electricity a periphery of the chuck, wherein the adjustment ring includes a fixing ring and a moving ring above the fixing ring, wherein: the fixing ring surrounds the electrostatic chuck or the base, and the upper surface of the fixing ring includes a supporting surface, and the supporting surface includes a groove having a bottom surface shape matching a support surface of the fixing ring, the moving ring including a first portion that is in contact with the electrostatic chuck and located below the edge of the substrate to be processed, the first portion having the first a height upper surface, a second portion having a second upper surface at a periphery of the first portion, a lower portion of the second portion of the moving ring including a projection matching a groove position on the lower fixing ring, a drive The device drives the second portion of the moving ring to move up and down between a lower first position and a higher second position, wherein the protrusion is moved when moved to the second position The lower end is still in the groove. The plasmonic processing apparatus of claim 1, wherein the protrusion and the groove of the moving ring have vertical side walls, and the distance between the side wall of the protrusion and the inner side wall of the groove is less than 1 mm when moving to the second position. . The plasma processing apparatus of claim 1, wherein the first portion and the second portion of the moving ring are simultaneously raised and lowered. The plasmonic processing apparatus of claim 1, wherein the first portion of the moving ring is fixed above the stationary ring. A plasma processing apparatus according to claim 1, wherein a transition portion is further included between the first portion and the second portion, and an upper surface of the transition portion gradually changes between the first height and the second height. The plasmonic processing apparatus of claim 2, wherein a gap exists between the lower surface of the moving ring and the support surface of the fixed ring when the moving ring is moved to the second position. The plasmonic processing apparatus of claim 1, wherein the adjustment ring is made of quartz or tantalum carbide or aluminum oxide. The plasma processing apparatus of claim 1, wherein the driving device comprises a driving rod connected to the moving ring through the fixing ring, and the lower end of the driving rod is connected to a controllable movement for driving the driving rod up and down Motor or cylinder. A method of operating a plasma processing apparatus according to claim 1, wherein after the plasma treatment of the substrate to be processed is completed a plurality of times, the driving device drives the second portion of the moving ring to rise to move The upper surface of the second portion of the ring has a fixed height difference relative to the surface of the substrate.