TWI812899B - Dual-station processor for realizing uniform exhaust, exhaust method thereof, and plasma processing equipment - Google Patents

Abstract

The invention discloses a dual-station processor that realizes uniform exhaust and an exhaust method thereof. The dual-station processor includes: two adjacently arranged plasma processing chambers, and a common exhaust pump. Each plasma chamber is provided with a base. Each plasma processing chamber is provided with a restriction ring around the periphery of the base. An exhaust area is provided below the restriction ring. A plurality of gas channels are provided on the restriction ring for discharging gas to In the exhaust area, the exhaust pump is in fluid communication with the exhaust area of each plasma processing chamber. The dual-station processor also includes a rotating ring arranged below the restriction ring, and the rotating ring is provided with a plurality of blocking areas. The plurality of blocking areas correspond to part of the gas channels of the restriction ring, and as the rotating ring rotates, the corresponding positions of the blocking areas and the gas channels are adjusted. The invention changes the airflow distribution in the exhaust area through partial blocking of the rotating ring, and at the same time uses asymmetrical rotational speed to achieve symmetry of the gas flow field.

Description

Dual-station processor that realizes uniform exhaust, its exhaust method, and plasma processing equipment

The present invention relates to the technical field of semiconductor equipment, and in particular to a dual-station processor that achieves uniform exhaust, an exhaust method thereof, and plasma processing equipment.

In equipment that uses reactive gases to process semiconductor substrates, such as plasma etching equipment, the reactive gases dissociate into plasma in the reaction chamber to process the semiconductor substrate. As the size of the semiconductor substrate gradually becomes larger, the processing process With the continuous improvement of precision requirements, the uniformity of semiconductor substrate processing has become a key parameter to measure the qualification of a semiconductor equipment.

Semiconductor equipment has a complex internal environment. In order to improve the efficiency of substrate processing, at least two reaction chambers can be installed on one processing equipment. Each reaction chamber includes at least one reaction chamber 70 surrounded by the outer wall 71 of the reaction chamber. A base 30 is provided in the reaction chamber to support the substrate, and the base has a temperature adjustment function; the air inlet element 72 controls the reaction gas to enter the reaction chamber, and the external radio frequency source 50 provides energy to dissociate the reaction gas into plasma; The exhaust device 40 discharges the reaction by-products from the reaction chamber while maintaining the pressure in the reaction chamber. The above components will affect the uniformity of the semiconductor substrate processing results. Among them, the temperature adjustment function of the control base, the uniform air intake of the air intake component and the uniform electric field distribution of the external radio frequency source in the reaction chamber can effectively adjust the etching uniformity of the semiconductor substrate. However, the uniform exhaust of the exhaust device Properties can also have a significant impact on the etching uniformity results of semiconductor substrates but are often ignored.

As shown in Figure 1, in conventional semiconductor equipment, in order to maintain a balanced gas pressure in the reaction chamber, a plasma confinement device 10 is usually provided downstream of the reaction chamber. This gas confinement device can allow reaction by-products of gases to be discharged from the reaction chamber. cavity, while confining the plasma in the reaction chamber to the plasma working area. The gas restriction device is usually arranged around the base and includes a main body and a plurality of holes or slot channels passing through the main body to realize the discharge of gas by-products. An exhaust device 40 is located under the adjacent areas of the plasma confinement devices 10 in the two reaction chambers. The area between the plasma confinement device 10 and the exhaust device 40 is the exhaust area, and the exhaust area surrounds the reaction chamber. Centrally located base perimeter. In order to ensure the synchronous operation of the processing processes in different reaction chambers, plasma processing equipment usually has two reaction chambers. The exhaust areas of multiple reaction chambers are often set in fluid communication and are in fluid communication with the common exhaust device 40 . Therefore, the exhaust device can only be arranged under the adjacent side walls of the two reaction chambers, and the reaction chamber and the exhaust device 40 are connected through an opening 45 , which will inevitably lead to different paths from the plasma confinement device 10 to the exhaust device 40 . Different lengths lead to different pressures under different plasma confinement devices 10, which in turn affects the uniformity of gas distribution on the surface of the semiconductor substrate and reduces the pass rate of the semiconductor substrate.

The purpose of the present invention is to provide a dual-station processor and its exhaust method and plasma processing equipment that achieve uniform exhaust. By arranging a rotating ring below the restriction ring, the exhaust area can be changed through partial blocking of the rotating ring. Air flow distribution, while using asymmetric speed to achieve symmetry of the gas flow field.

In order to achieve the above objects, the present invention is achieved through the following technical solutions: A dual-station processor that achieves uniform exhaust. The dual-station processor includes: two adjacently arranged plasma processing chambers, and a common exhaust pump. Each of the plasma chambers has A base is provided for supporting the substrate. Each plasma processing chamber is provided with a restriction ring around the periphery of the base. An exhaust area is provided below the restriction ring. The restriction ring has a plurality of a gas channel for discharging gas to an exhaust area; the exhaust areas of the two plasma processing chambers are at least partially adjacent to each other and in fluid communication with each other to form an adjacent ventilation area; the shared exhaust area A pump is disposed below the adjacent ventilation area and is in fluid communication with the exhaust area of each plasma processing chamber. Each restriction ring includes a first area and a second area, and the third One area corresponds to an area located above the adjacent ventilation area, and the second area is an area other than the first area. The characteristic is that the dual-station processor also includes a rotating ring, and the second area is an area other than the first area. The rotating ring is arranged below the restricting ring, and the rotating ring is provided with a plurality of blocking areas, and the plurality of blocking areas correspond to some gas channels of the restricting ring.

Preferably, the rotating ring is also provided with a plurality of breathable areas, and a blocking area is formed between two adjacent breathable areas.

Preferably, the surface area of the blocking area of the rotating ring located below the first area of the limiting ring is greater than the surface area of the blocking area of the rotating ring located below the second area of the limiting ring.

Preferably, the blocking area is located below the first area of the restriction ring.

Preferably, during one rotation of the rotating ring, the residence time of the blocking area of the rotating ring below the gas channel in the first area of the restricting ring is longer than the residence time of the gas channel located in the second area of the restricting ring. Dwell time below.

Preferably, the rotating ring includes an inner edge and an outer edge, and the blocking area is disposed between the inner edge and the outer edge.

A method to achieve uniform exhaust, which utilizes the above-mentioned dual-station processor, is characterized in that the method includes: According to the current process and the gas flow distribution in the plasma processing chamber, adjust the corresponding positions of the blocking area of the rotating ring and the gas channel of the restricting ring when the rotating ring rotates; By adjusting the corresponding positional relationship between the blocking area and the gas channel in the restricting ring part, the gas flow distribution in the exhaust area below the entire restricting ring is adjusted.

Preferably, during one rotation of the rotating ring, the residence time of the blocking area of the rotating ring below the gas channel in the first area of the restricting ring is longer than the residence time of the gas channel located in the second area of the restricting ring. Dwell time below.

Preferably, adjusting the gas flow distribution in the exhaust area below the entire restriction ring includes making the gas flow distribution in the exhaust area uniform.

A plasma processing equipment that achieves uniform exhaust, characterized by including the above-mentioned dual-station processor, and the gas injection device in each plasma processing chamber of each dual-station processor is connected to the reaction gas source.

Compared with the conventional technology, the present invention has the following advantages: The present invention sets a rotating ring below the restriction ring, and changes the airflow distribution in the exhaust area through partial blocking of the rotating ring, and at the same time uses asymmetrical rotational speed to achieve symmetry of the gas flow field; The rotation speed of the rotating ring is controllable, and the opening rate of the gas channels in each part of the limiting ring can be dynamically adjusted to meet the uniform exhaust requirements of all processes; The uniformity of reactive gas distribution on the surface of the substrate in the reaction chamber of the plasma processing equipment is improved, the uniformity of etching of the substrate is improved, and the qualification rate of the substrate is improved.

The present invention will be further elaborated below by describing a preferred specific embodiment in detail with reference to the accompanying drawings.

Figure 2 shows a cross-sectional view of a plasma processing device with dual reaction chambers provided according to an embodiment of the present invention. In other embodiments, the number of reaction chambers of the plasma processing device can be more than two. Its working principle and arrangement The gas structure is similar to the double reaction chamber structure.

The plasma reactor 100 shown in Figure 2 includes two adjacently arranged reaction chambers. The two reaction chambers are respectively surrounded by reaction chamber walls 101 and 101', and are provided with an adjacent side wall 105. During the plasma process, the plasma reactor 100 is usually set to a vacuum environment. At the beginning of the process, a gas injection device injects the reaction gas from the reaction gas source 160 into the plasma reactor 100 . The gas injection device can have various types. Form, according to different processes and the specific structure of the reaction chamber, it can be set as a flat-type gas shower head or other structures. In this embodiment, the gas injection device is set as a flat-type gas shower head 120 and 120'. The gas shower head 120 and 120' can inject the reaction gas evenly into the reactor. The material of the gas shower head is selected to be a material suitable for electrodes. The gas shower head can also be connected to the radio frequency power supply or ground as part of the parallel plate capacitor to generate Plasma. A base 130 and 130' is respectively provided below the gas shower head 120 and 120' to support the semiconductor substrate 135. Usually, an electrostatic chuck 133 and 133' is provided above the base 130 and 130', respectively. Through the electrostatic chuck 133 and 133 The generated electrostatic attraction fixes the semiconductor substrate 135 during the manufacturing process. The bases 130 and 130' are usually cylindrical and are located at the center of the bottom of the reaction chamber to provide a more symmetrical process environment, which is conducive to the smooth progress of the reaction process. The radio frequency power source systems 150 and 150' act on the bases 130 and 130', and between the gas shower head 120 and the base 130, the gas shower head 120' and the base 130' generate an electric field, which will spray the gas from the base. The reactive gas injected by the head 120 and the gas shower head 120' is dissociated into plasma, and the plasma is maintained to act on the semiconductor substrate. A limiting ring 110 is provided around the base 130, and a limiting ring 110' is provided around the base 130'. The area above the horizontal plane of the restriction rings 110 and 110' is the plasma processing area 102 and 102', and the area below the restriction ring 110 and 110' is the exhaust area 103 and 103'. The exhaust areas of a plurality of plasma processing chambers are at least partially adjacent to each other and in fluid communication with each other to form an adjacent ventilation area. An opening 145 is provided below the adjacent side walls 105 of the two reaction chambers to realize two reactions. The connection between the chamber exhaust areas 103 and 103'; the opening 145 simultaneously penetrates the bottom of the adjacent areas of the two reaction chambers, and an exhaust pump 140 is provided below the adjacent ventilation areas to realize that the two reaction chambers share one exhaust The pump is designed to discharge the gaseous by-products produced by the reaction process out of the reaction chamber.

Since the two reaction chambers have roughly the same structure, for the convenience of description, the structure of one reaction chamber is now selected for detailed introduction. Among them, the restriction ring 110 arranged around the base 130 includes a generally annular flow guide body 111 and a plurality of gas channels 112 arranged in the flow guide body 111 to facilitate the use of gas in the plasma processing area 102. The reaction gas and by-product gas enter the exhaust area 103 through this gas channel. The spent reaction gas and by-product gas include charged particles and neutral particles. The size of the gas channel 112 is set to be the same as that in the plasma. When charged particles pass through the gas channel 112, the charged particles can be neutralized while allowing neutral particles to pass. The exhaust areas 103 and 103' are annular areas surrounding the base 130 and the base 130'. Since the two reaction chambers share an exhaust pump 140, in order to ensure the symmetry of the exhaust rates of the two reaction chambers, the exhaust The pump 140 is disposed below the adjacent side walls 105 of the two reaction chambers. This will inevitably lead to different paths for the gases in the exhaust areas 103 and 103' of the two reaction chambers to reach the opening 145. Therefore, the gas in the exhaust area close to the opening 145 The reaction chamber is discharged through the exhaust pump along route A. The discharge rate is faster. The air pressure in this area is smaller. The used reaction gas and by-product gas above the corresponding restriction ring 110 and restriction ring 110' in this area will pass through faster. The gas channel enters the exhaust areas 103 and 103', and the gas in the exhaust area away from the opening 145 is discharged from the reaction chamber through the exhaust pump 140 along route B. The exhaust rate is slow, and the air pressure in this area is relatively large. There are corresponding restrictions in this area. The used reaction gas and by-product gas above the ring 110 and the restriction ring 110' will enter the exhaust area slowly through the gas channel, resulting in uneven gas distribution in the plasma processing area 102 and the plasma processing area 102' above the restriction ring. , which in turn leads to uneven processing of the semiconductor substrate in different areas.

Figure 3 shows a top view of a plasma processing device with dual reaction chambers according to the present invention. In the top view shown in Figure 3, two adjacent reaction chambers are arranged in parallel, and the exhaust areas of the two reaction chambers are shown in the circular dotted lines. Adjacent ventilation areas are adjacent to each other, and the exhaust pump is arranged below the adjacent ventilation areas, wherein each of the restriction rings 110 includes first areas 1101 and 1101' located above the adjacent ventilation areas and a first area 1101' located above the adjacent ventilation areas. Second areas 1102 and 1102' above the area outside the area.

Figure 4 is a bottom view of the rotating ring according to an embodiment of the present invention; Figures 5 and 6 are schematic views of the rotating ring of Figure 4 when it is located below the limiting ring of the plasma processing device. Referring to Figures 5 and 6 in conjunction with Figure 2, a rotating ring 20 and a rotating ring 20' are respectively provided below the limiting ring 110 and the limiting ring 110'. Figures 5 and 6 take as an example a rotating ring provided below the restriction ring 110 in the left reaction chamber of the dual-chamber plasma processing device of Figure 2. The rotating ring is provided with a plurality of blocking areas, the plurality of blocking areas correspond to part of the gas channels of the restricting ring, and as the rotating ring rotates, the corresponding positions of the blocking areas and the gas channels are adjusted.

As shown in Figure 4, in a specific embodiment, the rotating ring 20 includes an inner edge 201, an outer edge 202, and a blocking area 203 and a breathable area 204 disposed between the inner edge 201 and the outer edge 202. The inner edge 201 and the outer edge 202 form a hollow annular structure. The inner edge 201 corresponds to the inner ring below the restriction ring 110, and the outer edge 202 corresponds to the outer ring below the restriction ring 110. There is a gap between the inner edge 201 and the outer edge 202. The blocking block is the above-mentioned blocking area 203. It should be noted that the ratio of the blocking area 203 to the entire rotating ring 20 can be 1/8, 1/6, 1/4, etc., and the specific ratio can be based on actual work needs. In this embodiment, the blocking area 203 accounts for 3/4 of the entire rotating ring 20 . In addition, in this embodiment, the gas channel of the restricting ring can be a plurality of exhaust holes. When the rotating ring 20 is in a stationary state, the blocking area 203 of the rotating ring 20 is located below the first area of the restricting ring, and the rotating ring 20 is in a stationary state. The breathable area is located below the second area of the restricting ring; when the rotating ring is in rotational motion, during one rotation of the rotating ring 20, as shown in Figure 5, when the blocking area 203 is located in the first area of the restricting ring 110, the gas Below the channel, that is, when located above the exhaust pump 140, the blocking area 203 reduces the gas flow rate in the first area, while the gas flow rate in the second area does not change, which makes the gas flow distribution above the base 130 uniform or even distributed. Reverse; as shown in Figure 6, when the blocking area 203 is located below the second area of the restriction ring 110, because the blocking area 203 is located below the second area with a slower air flow velocity, further slowing down the gas flow velocity, then the top of the base 130 The gas flow distribution is more uneven. Therefore, the uniformity of gas exhaust can be adjusted by adjusting the residence time of the blocking area 203 in each different exhaust area. Further, the blocking area 203 of the rotating ring 20 is located below the gas channel in the first area of the limiting ring 110 The residence time is longer than the residence time under the gas channel located in the second area of the restriction ring 110 .

It should be noted that the rotating ring 20 can rotate non-uniformly at different angular velocities below the limiting ring 110, where the rotational speed of the rotating ring 20 in the adjacent ventilation area is smaller than the rotational speed in the non-adjacent ventilation area, so that corresponding to the phase The opening ratio of the restriction ring gas channel above the adjacent ventilation area is smaller than the opening ratio of the restriction ring gas channel above the non-adjacent ventilation area.

Referring to Figure 7, in other embodiments, the rotating ring is also provided with a plurality of breathable areas 204 and blocking areas 203, and a blocking area 203 is formed between two adjacent breathable areas 204. Specifically, the rotating ring includes The inner edge 201 and the outer edge 202 are provided with a plurality of blocking blocks at intervals between the inner edge 201 and the outer edge 202. The blocking blocks are blocking areas 203, and the area between the blocking blocks is a breathable area 204. Each blocking area 203 The areas of the blocking area 203 can be the same or different. The larger the area of the blocking area 203, the larger the covering surface area of the gas channel covering the restricting ring, and the more obvious the exhaust effect of the gas channel blocking the restricting ring. Preferably, it is located on the third side of the restricting ring. The surface area of the barrier region 203 beneath one region is greater than the surface area of the barrier region 203 beneath a second region of the confinement ring.

Furthermore, the blocking areas 203 of the above-mentioned rotating ring can be arranged at intervals and have different area areas. On the one hand, when the rotating ring is in a stationary state below the restricting ring, the area of the blocking area below the first area of the restricting ring is larger than that located under the first area of the restricting ring. The area of the blocking area below the second area of the restriction ring; on the other hand, when the rotating ring of this structure can rotate at a non-uniform speed below the restriction ring, its specific rotation speed and residence time can be referred to the above embodiments, and will not be described again. . By setting the area of the blocking area to vary in size, and cooperating with the rotation angular velocity, the opening rate of the restriction ring gas channel can be more accurately controlled to meet the requirements for exhaust uniformity.

It should be noted that in the actual process, there are many steps, and different gas parameters need to be set in each step. The gas flow field in the reaction chamber is often affected by gas pressure, gas flow rate and gas viscosity coefficient, and is different. The formulated gas will also change the gas flow field. Therefore, it is necessary to select an appropriate rotating ring angular speed based on the current gas flow field distribution to obtain the opening ratio of the restriction ring in different states, thereby meeting the uniform exhaust requirements of all processes.

To sum up, the present invention is a dual-station processor that achieves uniform exhaust, its exhaust method, and plasma processing equipment. By arranging a rotating ring below the restriction ring, the exhaust area is changed by partially blocking the rotating ring. airflow distribution, while using asymmetric speed to achieve symmetry in the gas flow field.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as limiting the present invention. Various modifications and alternatives to the present invention will be apparent to those of ordinary skill in the art upon reading the foregoing description. Therefore, the protection scope of the present invention should be limited by the appended patent application scope.

10:Plasma confinement device 100:Plasma reactor 101, 101’: reaction chamber wall 102,102’: Plasma treatment area 103,103’: exhaust area 105:Side wall 110, 110’: restriction ring 1101, 1101’: first area 1102, 1102’: Second area 111: Diversion body 112:Gas channel 120, 120’: Gas sprinkler head 135:Semiconductor substrate 130, 130’: base 133, 133’:Electrostatic chuck 140:Exhaust pump 150,150’: RF power source system 160: Reactive gas source 20, 20’: rotating ring 201:Inner edge 202:Outer edge 203: Breathable area 204: Blocking area 30: base 40:Exhaust device 45,145: Opening 50:External RF source 70:Reaction chamber 71: Outer wall of reaction chamber 72:Air intake components

Figure 1 is a cross-sectional view of a conventional plasma reactor; Figure 2 is a cross-sectional view of a plasma processing device with dual reaction chambers according to the present invention; Figure 3 is a top view of a plasma processing device with dual reaction chambers according to the present invention; Figure 4 is a bottom view of a rotating ring according to an embodiment of the present invention; Figures 5 and 6 are schematic diagrams of the rotating ring of Figure 4 when used in a plasma processing device; Figure 7 is a bottom view of a rotating ring according to another embodiment of the present invention.

100:Plasma reactor

101,101’: reaction chamber wall

102,102’: Plasma treatment area

103,103’: exhaust area

105:Side wall

110,110’: restriction ring

111: Diversion body

112:Gas channel

120,120’: Gas sprinkler head

130,130’: base

133,133’:Electrostatic chuck

135:Semiconductor substrate

140:Exhaust pump

150,150’: RF power source system

160: Reactive gas source

Claims (7)

A dual-station processor that achieves uniform exhaust. The dual-station processor includes: two adjacently arranged plasma processing chambers, and a common exhaust pump. Each plasma chamber is equipped with a A base that supports the substrate. Each plasma processing chamber is provided with a restriction ring around the periphery of the base. An exhaust area is provided below the restriction ring. The restriction ring has a plurality of gas channels for discharging the gas. Discharged to the exhaust area, the exhaust areas of the two plasma processing chambers are at least partially adjacent to each other and in fluid communication with each other to form an adjacent ventilation area, and the common exhaust pump is disposed in the adjacent ventilation area below, and simultaneously in fluid communication with the exhaust area of each plasma processing chamber, each restriction ring includes a first area and a second area, the first area is located corresponding to the adjacent ventilation area area above the area, the second area is an area other than the first area, wherein the duplex processor further includes a rotating ring, the rotating ring is arranged below the limiting ring, the rotating ring is arranged There are a plurality of blocking areas corresponding to part of the gas channels of the limiting ring. During the rotation of the rotating ring, the blocking area of the rotating ring is located in the first area of the limiting ring. The residence time below the gas channel is longer than the residence time below the gas channel in the second region of the restriction ring. The duplex bit processor that achieves uniform exhaust as described in claim 1, wherein the rotating ring is further provided with a plurality of breathable areas, and a blocking area is formed between two adjacent breathable areas. The duplex bit processor achieving uniform exhaust as described in claim 1, wherein the surface area of the blocking area of the rotating ring located below the first area of the limiting ring is larger than the surface area of the third area of the limiting ring. The surface area of the blocking area of the rotating ring beneath the second area. The duplex bit processor that achieves uniform exhaust according to any one of claims 1-3, wherein the rotating ring includes: an inner edge and an outer edge, and the blocking area is disposed on the inner edge and the outer edge. between outer edges. A method for achieving uniform exhaust using a dual-stage exhaust system as described in any one of claims 1-4 The station processor, wherein the method for achieving uniform exhaust includes: adjusting the blocking area of the rotating ring and the restriction ring when the rotating ring rotates according to the current process and the air flow distribution in the plasma processing chamber. The corresponding position of the gas channel; by adjusting the corresponding positional relationship between the blocking area and the gas channel of the restricting ring part, the gas flow distribution of the entire exhaust area below the restricting ring is adjusted; the rotating ring rotates once In the process, the residence time of the blocking area of the rotating ring below the gas channel in the first area of the restriction ring is longer than the residence time below the gas channel in the second area of the restriction ring. The method for achieving uniform exhaust according to claim 5, wherein the adjusting the gas flow distribution of the exhaust area below the entire restriction ring includes making the gas flow distribution of the exhaust area uniform. A plasma processing equipment that achieves uniform exhaust, which includes a dual-station processor as described in any one of claims 1-4, and each of the plasma processing chambers in each of the dual-station processors A gas injection device in the chamber is connected to a source of reactive gas.