CN103426710B - A kind of uniform plasma etching apparatus of air feed - Google Patents

Abstract

A plasma etching device with uniform gas supply, comprising a reaction chamber, in which a ground electrode and a radio frequency electrode are arranged oppositely and at intervals, and a gas supply device is also provided, and the gas supply device includes at least one uniform gas pipeline, the One end of the uniform gas pipeline is an air inlet, and the other end is closed, and a plurality of air outlet holes are arranged on the side wall of the uniform gas pipeline; the air inlet of the uniform gas pipeline is left outside the reaction chamber and inserted into the In the reaction chamber, the part of the uniform gas pipeline with air outlets, that is, the air outlet pipe part, is arranged between the ground electrode and the radio frequency electrode, and the air outlets all face the direction of the workpiece placed therebetween. The present invention also provides the gas supply device. The reaction chamber of the invention can well improve the uniformity of gas pressure distribution inside the reaction chamber, reduce the reject rate of workpieces, and increase the service life of the reaction chamber.

Description

A plasma etching device with uniform gas supply

technical field

The invention relates to a plasma etching device, in particular to a plasma etching device capable of uniform gas supply; the invention also provides a gas supply device for plasma etching.

Background technique

In the processing of VLSI, active particles (chloride ions, fluorine ions, etc.) in the plasma are usually used to etch, oxidize, PECVD (plasma-assisted chemical vapor deposition) and other treatments on semiconductors (single crystal silicon) craft.

Accompanying drawing 1 is the structural diagram of the reaction chamber of the plasma semiconductor etching device usually used in the prior art, and the reaction gas and the auxiliary gas enter the reaction chamber through the air inlet hole on the upper end cover 1 and the ground electrode 2 with the vent hole. In the chamber, a radio frequency bias is connected to the radio frequency electrode 3, and the gas is excited to form plasma in the space between the ground electrode 2 and the radio frequency electrode 3, and bombards the gas carried on the stage 4 under the action of the electric field force of the electrode. A semiconductor workpiece, such as a semiconductor wafer, initiates a series of physical and chemical actions that act as an etch. In this process, the more uniform the active particle concentration distribution on the surface of the workpiece, the better the processing result of the workpiece can be obtained. It has been shown that the uniformity of the gas distribution in the reaction chamber can have a significant effect on the uniformity of the reactive particle concentration on the surface of the workpiece.

However, the gas supply device in the prior art usually includes a gas distribution plate uniformly provided with a plurality of air outlet holes, and the gas distribution plate is fixed on the lower end of the ground electrode, so that the gas outlet holes and the air-permeable air on the ground electrode The holes are connected and a good seal is ensured at the junction of the two. In order to ensure the uniformity of gas distribution in the reaction chamber as much as possible, there are usually many gas outlet holes on the gas distribution plate and the distribution range is large, which makes the corresponding gas path structure in the ground electrode connected with it on the gas path It becomes complicated, which leads to an increase in processing difficulty and an increase in cost. In addition, the air outlet holes on the gas distribution plate are usually evenly distributed, while the air inlet holes are usually located at the center of the upper end cover, and the directions of the air inlet holes and the air outlet holes are the same (both along the vertical direction). When the air inlet is blown in, it tends to be quickly discharged from the nearest or facing air outlet, which inevitably results in more reaction gas flowing through the air outlet closer to the center, and the closer to the air outlet. The less reactive gas flows through the gas outlet at the edge, the pressure caused by the gas entering the reaction chamber through the gas distribution plate is significantly higher at the center of the ground electrode than at its edge, which leads to plasma The density of active particles is unevenly distributed along the radial direction of the workpiece, which affects the processing results of the workpiece.

Contents of the invention

The object of the present invention is to overcome the above-mentioned problems in the prior art, and provide a semiconductor etching device equipped with a gas supply device with a simple structure and capable of ensuring the uniformity of the reaction gas.

Another object of the present invention is to provide a gas supply device used in a semiconductor etching device.

In order to realize the primary purpose of the present invention, the present invention takes the following technical solutions:

A plasma etching device with uniform gas supply, including a reaction chamber for plasma etching, in which a ground electrode and a radio frequency electrode are arranged oppositely and at intervals, and a gas supply device is also provided, so The gas supply device includes at least one uniform gas pipeline, one end of the gas uniform pipeline is an air inlet, and the other end is closed, and a plurality of gas outlet holes are arranged on the side wall of the gas uniform pipeline; The mouth is left outside the reaction chamber and inserted into the reaction chamber in a sealed manner. The part of the uniform gas pipeline with the air outlet, that is, the air outlet pipe part, is arranged between the ground electrode and the radio frequency electrode, and the air outlets are all facing the place. The orientation of the workpiece in between.

When in use, the reaction gas is input from the air inlet of the uniform gas pipeline outside the reaction chamber, and the reaction gas is sprayed to the workpiece from the gas outlet hole on the gas outlet pipe in the space between the ground electrode and the radio frequency electrode. Due to the structure of the gas supply device provided by the present invention, all the air outlets are no longer facing the air inlet, and the gas will not short-circuit from the air inlet to part of the air outlets, but flow through each outlet on the air outlet pipe part. The pores are ejected, and its uniformity is greatly improved.

A gas supply device for a plasma etching device, comprising at least one uniform gas pipeline, one end of the gas uniform pipeline is an air inlet, and the other end is closed, and a plurality of gas outlet holes are arranged on the side wall of the gas uniform pipeline ; and the air outlets are: when the uniform gas pipeline is placed in the reaction chamber of the etching device, they all face the direction of the workpiece placed therebetween.

Due to the length of the uniform gas pipeline, the gas outlet near the air inlet will emit a large amount of gas, while the gas outlet away from the air inlet will emit a small amount of gas, so there may be a small amount of gas ejected. Inhomogeneity, in order to make the jet more uniform, the spacing and aperture of the air outlet can be further designed as the following structure:

The distances between the air outlets arranged on the uniform gas pipeline are different, the closer to the closed end, the smaller the distance between adjacent air outlets; and/or, the diameter of the air outlets arranged on the uniform gas pipeline is Differently, the closer to the closed end, the larger the diameter of the air outlet.

In order to avoid the influence of the length of the uniform gas pipeline on the uniformity of the gas injection of each gas outlet, two or more uniform gas pipelines can be provided, and the air inlets arranged outside the reaction chamber are connected separately or in parallel to communicate with the reaction gas source. connect.

The uniform gas pipeline is twisted and coiled, and the coiled area and shape of the coiled gas uniform pipeline can be flexibly adjusted according to the size and shape of the etched surface of the workpiece, thus, the effective utilization rate of the reaction gas can be provided without having to As with the technology, the air injection area is fixed and cannot be adjusted with the size of the workpiece. Therefore, the present invention can solve energy problems and reduce production costs.

In the etching device, the coiled uniform gas pipeline may be fixed on the surface of the electrode opposite to the workpiece.

The fixing structure of the uniform gas pipeline on the electrode is preferably: a fixed groove is provided on the corresponding side of the electrode, and the cross-sectional shape of the fixed groove matches the cross-sectional shape of the uniform gas pipeline, so that the uniform gas pipeline snapped into the fixing slot.

The air outlet pipe part is coiled into a helical shape, and its closed end is located in the middle of the helix, and the closed end can also be located outside the helix.

If there are two gas distribution pipes, they can be coiled into a spiral shape, the closed end of one of which is located in the middle of the spiral, and the closed end of the other is located outside the spiral, and the two gas distribution pipes are inserted alternately. connected together.

The cross-sectional shape of the air outlet is preferably circular, and its diameter is preferably 2-5mm.

The gas supply device may also include a scroll spring, and the gas equalization pipeline is fixed on the scroll spring along the direction of the spring wire of the scroll spring so as to abut against the spring wire.

The gas distribution pipeline is preferably bonded to the spring wire of the scroll spring.

The spiral spring is fixed in the space between the ground electrode and the radio frequency electrode of the reaction chamber, or on the surface of the ground electrode facing the radio frequency electrode.

A rotating shaft is fixedly arranged at one end of the scroll spring wire, a rotating device is arranged on the rotating shaft, and a ratchet mechanism is arranged between the rotating shaft and the fixing member fixing the scroll spring. By rotating the rotating shaft, the spacing of the scroll spring wires can be adjusted, and then the density of the air outlet holes can be adjusted.

Specifically, the scroll spring may be a planar scroll spring, which is fixed on the side of the ground electrode facing the radio-frequency electrode, and the rotating shaft is fixed at the end of the wire at the center of the planar scroll spring, which is fixed to At the center of the ground electrode, the other end of the spring wire is rigidly connected with the ground electrode.

A clamping piece may be provided on the ground electrode, and a ratchet is sheathed on the rotating shaft, which is axially movable and fixed on the rotating shaft, and matches with the clamping piece to limit the rotation of the rotating shaft. The above displacement stroke makes the ratchet engage or disengage from the engaging member. A positioning mechanism is also provided between the ratchet and the rotating shaft so that the ratchet is positioned axially on the rotating shaft.

By rotating the ratchet mechanism, the pitch of the volute spring can be adjusted, thereby changing the pitch of the uniform gas pipeline, and then changing the distribution density of the air outlet.

The ground electrode is installed on the upper end cover of the reaction chamber by screws.

The etching device provided by the present invention and the gas supply device therein can obtain a more uniform reaction gas between the ground electrode and the radio frequency electrode, compared with the gas supply device composed of the gas distribution plate and the ground electrode in the prior art , has the advantages of simple structure, easy manufacture, convenient installation, easy replacement, and low cost; while the gas enters the uniform gas pipeline from one end and is discharged from multiple air outlet holes on the pipe body, since all the air outlet holes will not Facing the air inlet, it effectively avoids the unfavorable situation in the prior art that the reaction gas is mainly discharged from the gas outlet near the center and less from the gas outlet near the edge, ensuring the uniform distribution of the gas in the reaction chamber sex. At the same time, the uniform distribution of the reaction gas in the reaction chamber can be better ensured through the uneven distribution of the air outlets or the different settings of the diameters of the air outlets.

Description of drawings

FIG. 1 is a schematic structural diagram of an etching device in the prior art.

FIG. 2 is a schematic structural diagram of an etching device provided by the present invention.

Fig. 3 is a structural schematic diagram of a structure of a uniform gas pipeline of the gas supply device provided by the present invention.

Fig. 4 is a structural schematic diagram of another structure of the uniform gas pipeline of the gas supply device provided by the present invention.

Fig. 5 is a schematic structural diagram of another gas supply device provided by the present invention.

FIG. 6 is a schematic structural diagram of a pitch of the gas supply device shown in FIG. 5 .

FIG. 7 is a schematic structural diagram of changing the pitch of the gas supply device shown in FIG. 5 .

detailed description

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in Figure 2, the semiconductor etching device of the present invention includes a reaction chamber for performing plasma etching, the reaction chamber includes an upper end cover 1, a lower end cover 5, and a side wall 6, and the reaction chamber A ground electrode 2 and a radio frequency electrode 3 are arranged inside, the ground electrode 2 is installed on the upper end cover 1 of the reaction chamber by screws, and the stage carrying semiconductor workpieces is arranged on the radio frequency electrode 3, and the inside of the reaction chamber is also A gas supply device for supplying reaction gas to the semiconductor workpiece, and a workpiece pick-and-place device for picking and placing the semiconductor workpiece are provided. The reaction gas and auxiliary gas enter the reaction chamber through the gas supply device, and the gas is excited to form plasma in the space between the ground electrode 2 and the radio frequency electrode 3, and bombards the semiconductor under the action of the electric field force of the electrode A workpiece, such as a semiconductor wafer, acts as an etch.

Regarding the gas distribution device of the present invention, as shown in Figure 3, the gas supply device includes a uniform gas pipeline 7, and the shape of the uniform gas pipeline 7 is in the shape of a vortex line, one end of which is an air inlet 8, and the other end is closed, The pipe body 9 of the uniform gas pipeline 7 is provided with a plurality of air outlet holes 10 facing downward, that is, toward the direction of the semiconductor workpiece. The air inlet end of the uniform gas pipeline 7 is directly bent upward, passes through the ground electrode 2 and the upper end cover 1, and is placed outside the reaction chamber, so as to be connected to an external gas source device. Since the flow direction of the reaction gas after entering the uniform gas pipeline 7 is approximately perpendicular to the direction of each air outlet 10, there is no air outlet facing the air inlet like the air outlet on the gas distribution plate in the prior art. The nearest air outlet of the air port will not be obviously prior to other air outlets like the gas distribution plate in the prior art. Therefore, the reaction gas entering the uniform gas pipeline 7 will not be quickly discharged from a small number of air outlets. In this way, the uniformity of the reaction gas in the reaction chamber can be improved.

In the situation shown in FIG. 3 , the air inlet 8 is located at the end of the vortex line away from the center, and the end near the center is a closed end. However, it is conceivable that the air inlet 8 can also be located at the end of the swirl line near the center, and the end far away from the center is a closed end.

The cross-sectional shape of the air outlet hole 10 is preferably circular, with a diameter of 2-5 mm, such as 5 mm. The cross-sectional shape of the air outlet can also be rectangular or elliptical.

Further, considering that when the reactant gas flows in the uniform gas pipeline 7, the gas pressure in the uniform gas pipeline 7 will gradually decrease due to the continuous shunting effect of the gas outlet 10. Therefore, in order to further improve the reactant gas in the reaction Uniformity in the chamber, the air outlet holes 10 may be unevenly distributed on the tube body 9 , and the longer the pipeline distance from the air inlet 8 , the denser the distribution of the air outlet holes 10 . For the same reason, optionally, the diameters of the air outlet holes 10 may be different, and the longer the pipeline distance from the air inlet 8 is, the larger the diameter of the air outlet holes 10 is.

The gas distribution pipeline 7 can be directly installed on the lower end of the ground electrode 2 . Preferably, the lower end of the ground electrode 2 can be provided with a groove, and the gas distribution pipeline can be installed in the groove. It is conceivable that no matter whether grooves are provided, the installation of the uniform gas pipeline 7 at the lower end of the ground electrode 2 is very convenient. Since the gas uniform pipeline itself forms a complete gas circuit structure, there is no sealed gap between the pipe body and the ground electrode. Demand, which also makes the replacement of the uniform gas pipeline can be carried out conveniently. Therefore, in actual work, according to the processing results of the workpiece, it is possible to easily replace the uniform gas pipeline with different parameters at any time to ensure that the processing results are satisfactory. The gas distribution plate in the prior art obviously cannot do this.

The uniform gas pipeline is twisted and coiled, and the coiled area and shape of the coiled uniform gas pipeline can be flexibly adjusted according to the size and shape of the etched surface of the workpiece. The gas line is coiled for a set length near the middle in the helical groove on the ground electrode. Thus, the effective utilization rate of the reaction gas can be improved, and it is not necessary to fix the gas injection area as in the prior art, and the same total amount of gas supply is required whether the workpiece to be processed is large or small. Therefore, the present invention can solve energy problems and reduce production costs.

Instead of being coiled in a helical form, for example, it can also be coiled in a serpentine form.

In order to avoid the influence of the length of the uniform gas pipeline on the uniformity of the gas injection of each gas outlet, two or more uniform gas pipelines can be provided, and the gas inlets arranged outside the reaction chamber are connected in parallel with the reaction gas source.

There can be two uniform gas pipelines, which can be coiled into a spiral shape, the closed end of one of which is located in the middle of the spiral, and the closed end of the other is located outside the spiral, and the two uniform gas pipelines are inserted alternately. connected together, as shown in Figure 4. In this way, the gas flow between the ground electrode and the RF electrode can be made more uniform.

As shown in Figures 5, 6 and 7, the gas supply device can also include a scroll spring 11, and the gas distribution pipeline 9 is fixed against the spring wire along the direction of the spring wire of the scroll spring 11. on the scroll spring. In this example, the even gas pipeline 9 is bonded to the spring wire of the scroll spring 11 .

The spiral spring 11 is fixed on the surface of the ground electrode facing the radio frequency electrode.

One end of the spring wire in the middle of the scroll spring is fixedly provided with a rotating shaft 110, and a rotating device (not shown in the figure) is arranged on the rotating shaft 110, and the rotating shaft 110 and the fixed member fixing the scroll spring are, for example, A ratchet mechanism is arranged between the radio frequency electrodes. By rotating the rotating shaft, the spacing of the scroll spring wires can be adjusted, and then the density of the air outlet holes can be adjusted.

Specifically, the scroll spring 11 may be a planar scroll spring, which is fixed on the side of the ground electrode 2 facing the radio frequency electrode, and the rotating shaft 11 is fixed at the end of the coil spring at the center of the planar scroll spring. , which is fixed at the center of the ground electrode 2, and the other end of the spring wire is rigidly connected with the ground electrode 2.

The ratchet mechanism includes a clip and a ratchet, the clip can be arranged on the ground electrode 2, and a ratchet is sleeved on the shaft, which is axially movable and fixed on the shaft. The locking member is matched to limit the rotation of the rotating shaft, and the displacement stroke of the ratchet on the rotating shaft makes the ratchet engage or disengage from the engaging member. A positioning mechanism, such as a set screw, is also provided between the ratchet and the rotating shaft, so that the ratchet is axially positioned on the rotating shaft.

By rotating the ratchet mechanism, the pitch of the volute spring can be adjusted, thereby changing the pitch of the uniform gas pipeline, and then changing the distribution density of the air outlet.

The uniformity and stability of the gas flow field between the RF electrode and the ground electrode in the etching device play a key role in the generation and maintenance of plasma, and are important factors affecting various particle parameters in the plasma. In order to analyze the effect of the distribution pattern of the vent holes on the electrode on the plasma, the design only needs to be manually adjusted to achieve different distribution patterns of the vent holes, which overcomes the current shortage of frequent replacement of the vent device, which can greatly improve the utilization of the experimental device rate and save energy.

Claims (8)

1. the uniform plasma etching apparatus of air feed, comprise the reaction chamber for carrying out plasma etching, in this reaction chamber relatively and interval ground-electrode and radio-frequency electrode are set, also it is provided with gas supply device, it is characterized in that: described gas supply device comprises at least one even air pipe, this even air pipe one end is inlet mouth, and the other end is closed, and arranges multiple production well on the sidewall of this even air pipe; Described even air pipe, its inlet mouth is stayed outside reaction chamber and is inserted described reaction chamber with sealing, there is described even air pipe part and the escape pipe part of production well, arrange between described ground-electrode and radio-frequency electrode, and production well is all towards the direction of the workpiece being placed between described ground-electrode and radio-frequency electrode; The described even air pipe of coiling is fixed on the surface of level of the electrode relative with described workpiece; Described escape pipe part is coiled into spirrillum; Described even air pipe pickup groove or plane scroll spring are fixed;

The fixing mode of described pickup groove is: offering pickup groove on the respective horizontal face of the electrode relative with described workpiece, the section form of this pickup groove is mated mutually with the section form of described even air pipe so that described even air pipe fixes in described pickup groove; The corresponding escape pipe part of described pickup groove is coiled into spirrillum;

The fixing mode of described plane scroll spring is: be provided with a plane scroll spring on the respective horizontal face of the electrode relative with described workpiece, and described even air pipe is fixed on described scroll spring along the subsides of moving towards of the spring silk of described scroll spring by spring silk.

2. the uniform plasma etching apparatus of air feed according to claim 1, it is characterised in that: the spacing of the described production well being located on described even air pipe is different, and the closer to described blind end, the spacing of adjacent production well is more little; And/or, the aperture of the described production well being located on described even air pipe is different, and the closer to described blind end, the diameter of production well is more big.

3. the uniform plasma etching apparatus of air feed according to claim 1, it is characterised in that: described even air pipe, its blind end is positioned at the centre of spiral, or, described blind end is positioned at the outside of spiral; Or, described even air pipe is two, and it is all coiled into spirrillum, and wherein the described blind end of is positioned at the centre of spiral, and the described blind end of another root is positioned at the outside of its spiral, and two even air pipes interlock and are plugged in together; Or, described production well cross-sectional shape is circular.

4. the uniform plasma etching apparatus of air feed according to claim 3, it is characterised in that: described production well diameter is 2-5mm.

5. the uniform plasma etching apparatus of air feed according to claim 1, it is characterised in that: described even air pipe is two or more than two, and it is arranged on the difference of the inlet mouth outside reaction chamber or connection in parallel, to be connected with reacting gas source.

6. the uniform plasma etching apparatus of air feed according to claim 1, it is characterized in that: described scroll spring is fixed in the space between the ground-electrode of described reaction chamber and radio-frequency electrode, or be fixed on ground-electrode towards on the surface of radio-frequency electrode; Or, it is fixedly installed a rotating shaft in one end of described scroll spring spring silk, this rotating shaft arranges a wheelwork, between the stationary member of this rotating shaft and fixing described scroll spring, be provided with a ratchet mechanism.

7. the uniform plasma etching apparatus of air feed according to claim 6, it is characterized in that: described scroll spring is plane scroll spring, its be fixed on ground-electrode towards on the side of radio-frequency electrode, described rotating shaft is fixed on the spring silk end being positioned at center of described plane scroll spring, it is fixed on described ground-electrode center, linking together with ground-electrode of the other end rigidity of spring silk; Or, arranging holding firmware on described ground-electrode, a sheathed ratchet in described rotating shaft, it can axially movably be installed in this rotating shaft, mating to limit axis of rotation with described holding firmware, the displacement stroke of described ratchet in rotating shaft makes described ratchet combine or depart from conjunction with described holding firmware.

8. the uniform plasma etching apparatus of air feed according to claim 7, it is characterised in that: also it is provided with locating mechanism between described ratchet and described rotating shaft and makes ratchet axial location in rotating shaft.