CN217405372U

CN217405372U - Chemical dry etching device

Info

Publication number: CN217405372U
Application number: CN202221130829.XU
Authority: CN
Inventors: 荀延雷
Original assignee: Haike Jiaxing Electric Power Technology Co ltd
Current assignee: Haike Jiaxing Electric Power Technology Co ltd
Priority date: 2022-05-12
Filing date: 2022-05-12
Publication date: 2022-09-09
Anticipated expiration: 2032-05-12

Abstract

The application discloses chemical dry etching device, it includes: the free radical generating unit comprises a gas source, a gas supply pipeline and a power supply mechanism, wherein the gas source is communicated with an inlet of the gas supply pipeline, the power supply mechanism comprises a first electrode and a second electrode which are oppositely arranged, an electric field is formed between the first electrode and the second electrode, and the electric field is used for ionizing gas generated by the gas source to generate free radicals; the etching cavity is communicated with an outlet of the air supply pipeline, an electrostatic chuck for placing a piece to be etched is arranged in the etching cavity, a rotating assembly is arranged below the electrostatic chuck and used for driving the electrostatic chuck to rotate so as to drive the piece to be etched to rotate, and the free radicals enter the etching cavity through the air supply pipeline so as to etch the piece to be etched; and the air exhaust mechanism is communicated with the etching cavity and is used for exhausting free radicals and/or gas in the etching cavity.

Description

Chemical dry etching device

Technical Field

The application relates to a chemical dry etching device, in particular to a chemical dry etching device for silicon carbide crystals, belonging to the technical field of semiconductors.

Background

The silicon carbide power device is suitable for extreme working environments such as high temperature, high pressure, high radiation and the like by virtue of excellent performance, but the silicon carbide device still can generate larger heat when working in the high-power and extreme environments, and the power loss of the device can be effectively reduced and the heat dissipation performance of the device can be improved by reducing the thermal resistance of the substrate part of the device. At present, the preparation of large-size ultrathin silicon carbide mainly adopts a wafer back thinning machine to grind and thin the back of a silicon carbide wafer so as to reduce the thermal resistance of a substrate and enhance the performance of a device.

However, since silicon carbide crystals have a high hardness, damage may occur to the crystal surface during the thinning process, resulting in roughness on the wafer surface. Because the hardness of the silicon carbide crystal is extremely high, the back damage cannot be reduced by adopting a chemical wet etching method. At present, a plasma etching process is widely used to improve the back damage of silicon carbide crystal, i.e. a certain radio frequency power (usually MHz in order of magnitude) is used to dissociate the reaction gas input into a plasma, and the plasma is used to etch the substrate placed inside the reaction device. However, since the plasma generally needs to be accelerated by an electric field to perform directional motion, and the plasma accelerated by the electric field has a high moving speed, it is highly likely to cause secondary damage to the crystal when reaching the crystal surface, and although etching is performed on a high portion of the crystal surface, damage is also caused on a low point, and it is difficult to obtain a smooth and highly uniform silicon carbide crystal surface.

SUMMERY OF THE UTILITY MODEL

In order to solve the above problems, the present application proposes a chemical dry etching apparatus. The device has no plasma with positive and negative electricity in the etching process, so the reaction process is mild, the problem of damage to the to-be-etched piece caused by the excessively fast free radical movement process is solved, the etching uniformity can be ensured, and the to-be-etched piece with small total thickness deviation and higher quality is processed; in addition, the surface of the piece to be etched can be ensured to be uniformly contacted with the free radicals, the uneven surface etching of the piece to be etched caused by the uneven concentration of the free radicals is prevented, and the uniformity of etching is further ensured.

According to an aspect of the present application, there is provided a chemical dry etching apparatus including:

the free radical generating unit comprises a gas source, a gas supply pipeline and a power supply mechanism, wherein the gas source is communicated with an inlet of the gas supply pipeline, the power supply mechanism comprises a first electrode and a second electrode which are oppositely arranged, an electric field is formed between the first electrode and the second electrode, and the electric field is used for ionizing gas generated by the gas source to generate free radicals;

the etching chamber is communicated with an outlet of the air supply pipeline, an electrostatic chuck for placing a piece to be etched is arranged in the etching chamber, a rotating assembly is arranged below the electrostatic chuck and used for driving the electrostatic chuck to rotate so as to drive the piece to be etched to rotate, and the free radicals enter the etching chamber through the air supply pipeline so as to etch the piece to be etched;

and the air exhaust mechanism is communicated with the etching cavity and is used for exhausting free radicals and/or gas in the etching cavity.

Optionally, the rotating assembly comprises a power mechanism and a connecting shaft, one end of the connecting shaft is connected with the power mechanism, the other end of the connecting shaft is connected with the electrostatic chuck,

the power mechanism drives the connecting shaft to rotate, and then drives the electrostatic chuck to rotate so as to drive the to-be-etched piece to rotate.

Optionally, the bottom wall of the etching chamber is provided with an installation opening, the rotating assembly further comprises a sealing plate and a supporting plate, the supporting plate is clamped at the installation opening, the supporting plate and the sealing plate are arranged in a matched manner to form a cavity structure, the power mechanism is arranged in the cavity structure,

the connecting shaft penetrates through the sealing plate to be connected with the electrostatic chuck, the connecting shaft is connected with the sealing plate through a bearing, and the connecting shaft is used for driving the electrostatic chuck to rotate.

Optionally, the side wall of the etching chamber is provided with an installation opening, the rotating assembly further comprises a sealing plate and a supporting plate, the supporting plate is clamped at the installation opening, the supporting plate and the sealing plate are arranged in a matched manner to form a cavity structure, the power mechanism is arranged in the cavity structure, the sealing plate is connected with the electrostatic chuck,

the connecting shaft is sleeved with a gear, the sealing plate is provided with a gear groove matched with the gear, and the connecting shaft drives the gear to rotate so as to drive the sealing plate to rotate so as to drive the electrostatic chuck to rotate.

Optionally, the upper surface of the sealing plate is a horizontal surface.

Optionally, the outlet of the air supply line is disposed above the electrostatic chuck and opposite the electrostatic chuck.

Optionally, a buffer plate is arranged in the etching cavity, a plurality of through holes are formed in the buffer plate, and the free radicals pass through the through holes and reach the surface of the to-be-etched piece.

Optionally, the gas supply pipeline and/or the buffer plate are made of quartz.

Optionally, the first electrode and the second electrode are respectively located outside the air supply pipeline and are oppositely arranged.

Optionally, the radical generation unit further comprises a flow control valve for controlling the gas flow of the gas source.

Benefits that can be produced by the present application include, but are not limited to:

1. according to the chemical dry etching device provided by the application, gas is ionized into free radicals by arranging the first electrode and the second electrode, the free radicals are diffused to the surface of a piece to be etched under the action of self energy and react with the piece to be etched to generate volatile substances so as to finish etching of the piece to be etched, and no plasma with positive and negative electricity is generated in the etching process, so that the reaction process is mild, the problem that the piece to be etched is damaged due to the fact that the free radicals move too fast is solved, the etching uniformity can be ensured, and the piece to be etched with small total thickness deviation and higher quality is processed; the electrostatic chuck is used for placing the piece to be etched, so that the piece to be etched is ensured to be uniform in adsorption force, and uneven etching caused by uneven local stress is avoided; in addition, through setting up the rotatory rotating assembly that can drive the electrostatic chuck, guarantee to treat that the surface of sculpture piece evenly contacts the free radical, prevent to treat that sculpture piece surface sculpture is uneven because of the inhomogeneous and lead to of free radical concentration, further guarantee the homogeneity of sculpture.

2. According to the chemical dry etching device provided by the application, the supporting disc is clamped at the mounting opening, so that the sealing structure of the etching cavity is ensured, and gas can be dissociated into free radicals; in addition, through setting up closing plate and backup pad vacuole formation structure, the connecting axle is direct to link to each other with electrostatic chuck to for power unit provides installation space, avoid the interference of free radical, extension power unit's life, and simple structure.

3. The application provides a chemical dry etching device mutually supports through setting up the tight gear of assembly and gear groove to make the connecting axle rotate through this gear structure drive closing plate, and then the drive electrostatic chuck rotates, can further guarantee the leakproofness of cavity structure, avoid the interference of free radical to power unit, extension power unit's life, and can avoid producing impurity.

4. The application provides a chemical dry etching device, the export setting through setting up the air supply line has shortened air supply line export and electrostatic chuck's distance in electrostatic chuck top to reduce the stroke of free radical, improved sculpture efficiency.

5. The chemical dry etching device provided by the application can control the gas flow by setting the flow control valve, so that the concentration of free radicals can be controlled, the etching speed of an etching piece to be etched is further controlled, and the etching process is more controllable.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic diagram of a chemical dry etching apparatus according to an embodiment of the present disclosure;

fig. 2 is a schematic view of a rotating assembly in the chemical dry etching apparatus according to the embodiment of the present application.

List of parts and reference numerals:

1. etching the cavity; 2. a gas supply line; 3. a first electrode; 4. a second electrode; 5. an electrostatic chuck; 6. a power mechanism 7 and a connecting shaft; 8. a sealing plate; 9. a support disc; 10. a gear; 11. a buffer plate.

Detailed Description

In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example in conjunction with the accompanying drawings.

In order that the above objects, features and advantages of the present application can be more clearly understood, the present application will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

In addition, in the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like indicate orientations or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, a first feature is "on" or "under" a second feature such that the first and second features are in direct contact, or the first and second features are in indirect contact via an intermediary. In the description of the present specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The cleaning device can be used for etching any semiconductor, and can be used for etching any semiconductor as long as the cleaning device can react with free radicals of etching gas to realize etching. In this embodiment, the etching of the sic wafer is taken as an example, but not limited to the etching of the sic wafer.

As shown in fig. 1-2, an embodiment of the present application discloses a chemical dry etching apparatus, which includes: a free radical generating unit, an etching cavity 1 and an air exhaust mechanism. The free radical generating unit comprises a gas source, a gas supply pipeline 2 and a power supply mechanism, wherein the gas source is communicated with an inlet of the gas supply pipeline 2, the power supply mechanism comprises a first electrode 3 and a second electrode 4 which are oppositely arranged, an electric field is formed between the first electrode 3 and the second electrode 4, and the electric field is used for dissociating gas generated by the gas source to generate electrically neutral free radicals; the etching cavity 1 is communicated with an outlet of the air supply pipeline 2, an electrostatic chuck 5 for placing a piece to be etched is arranged in the etching cavity 1, a rotating assembly is arranged below the electrostatic chuck 5 and used for driving the electrostatic chuck 5 to rotate so as to drive the piece to be etched to rotate, and free radicals enter the etching cavity 1 through the air supply pipeline 2 so as to etch the piece to be etched; the air exhaust mechanism is communicated with the etching chamber 1 and is used for exhausting free radicals and/or gas in the etching chamber 1. The gas is ionized into free radicals by arranging the first electrode 3 and the second electrode 4, the free radicals are diffused to the surface of the silicon carbide wafer under the action of self energy and react with the silicon carbide wafer to generate volatile substances so as to finish the etching of the silicon carbide wafer, and no plasma with positive and negative electricity appears in the etching process, so that the reaction process is mild, an electric field does not need to be accelerated to drive charged ions, the damage to the surface of the silicon carbide wafer caused by charged ion bombardment is reduced, the etching uniformity can be ensured, and the silicon carbide wafer with small total thickness deviation and higher quality is processed; the electrostatic chuck 5 is used for placing a piece to be etched, so that the uniform adsorption force on the silicon carbide wafer is ensured, and the nonuniform etching caused by the nonuniform local stress is avoided; in addition, through setting up the rotating assembly that can drive electrostatic chuck 5 is rotatory, guarantee that the surface of carborundum wafer evenly contacts the free radical, prevent to lead to the uneven of wafer surface sculpture because of the free radical concentration is inhomogeneous, further guarantee the homogeneity of sculpture.

Specifically, the frequency of the electric field generated by the first electrode 3 and the second electrode 4 in this embodiment is 2GHz to 3GHz, so as to ensure that the gas is dissociated into uncharged radicals.

Specifically, the present embodiment is not limited to the type of gas, as long as the silicon carbide crystal can be etched, and may be, for example, O ₂ And CF ₄ The mixed gas of (2) and the like, but not limited to the above.

Specifically, the material of the gas supply pipeline 2 and the inner wall of the etching chamber 1 is not limited in this embodiment. Preferably, the gas supply pipeline 2 and the inner wall of the etching chamber 1 are made of quartz to prevent impurities generated by the reaction between the gas supply pipeline 2 and/or the inner wall of the etching chamber 1 and the radicals.

As an implementation mode, the rotating assembly comprises a power mechanism 6 and a connecting shaft 7, one end of the connecting shaft 7 is connected with the power mechanism 6, the other end of the connecting shaft 7 is connected with the electrostatic chuck 5, and the power mechanism 6 drives the connecting shaft 7 to rotate, so as to drive the electrostatic chuck 5 to rotate, so as to drive the to-be-etched piece to rotate. The arrangement mode can ensure that the surface of the silicon carbide wafer is uniformly contacted with free radicals, and the etching uniformity is ensured.

Specifically, the type of the power mechanism 6 is not limited in this embodiment, as long as the electrostatic chuck 5 can be driven to rotate, and the power mechanism may be, for example, a rotating motor.

As an embodiment not shown, the mounting opening has been seted up to the diapire in sculpture chamber 1, and rotating assembly still includes closing plate 8 and supporting disk 9, and supporting disk 9 block is in mounting opening department, and supporting disk 9 sets up with closing plate 8 cooperation to form the cavity structure, power unit 6 sets up in the cavity structure, and connecting axle 7 passes closing plate 8 and links to each other with electrostatic chuck 5, and connecting axle 7 passes through the bearing with closing plate 8 and is connected, and connecting axle 7 is used for driving electrostatic chuck 5 and rotates. The supporting disc 9 is clamped at the mounting opening, so that the sealing structure of the etching cavity 1 is ensured, and gas can be dissociated into free radicals; in addition, through setting up closing plate 8 and backup pad formation cavity structure, connecting axle 7 directly links to each other with electrostatic chuck 5 to for power unit 6 provides installation space, avoid the interference of free radical, prolong power unit 6's life, and simple structure.

Specifically, the material of the sealing plate 8 and the supporting plate 9 is not limited in this embodiment. Preferably, the sealing plate 8 and the support plate 9 are made of quartz material in order to prevent impurities from being generated by the reaction between the sealing plate 8 and the support plate 9 and the radicals.

As another kind of embodiment, the installing port has been seted up to the lateral wall in sculpture chamber 1, rotating assembly still includes closing plate 8 and supporting disk 9, supporting disk 9 block is in installing port department, supporting disk 9 sets up with the cooperation of closing plate 8, in order to form the cavity structure, power unit 6 sets up in the cavity structure, closing plate 8 links to each other with electrostatic chuck 5, connecting axle 7 outside cover is equipped with gear 10, closing plate 8 has been seted up with gear 10 complex gear groove, connecting axle 7 drives gear 10 and rotates, and then drive closing plate 8 and rotate, in order to drive electrostatic chuck 5 and rotate. Through setting up gear 10 that the assembly is tight and gear groove mutually supports to make connecting axle 7 rotate through this gear 10 structure drive closing plate 8, and then drive electrostatic chuck 5 rotates, can further guarantee the leakproofness of cavity structure, avoid the interference of free radical to power unit 6, prolong power unit 6's life, and can avoid producing impurity.

Preferably, the upper surface of the sealing plate 8 is a horizontal surface. The upper surface of the sealing plate 8 is a horizontal plane, so that the same stroke of free radicals from the gas supply pipeline to the surface of the silicon carbide wafer is ensured, and the uniformity of etching the surface of the wafer is further ensured.

In one embodiment, the outlet of the gas supply line 2 is disposed above the electrostatic chuck 5 and opposite the electrostatic chuck 5. The outlet of the gas supply pipeline 2 is arranged above the electrostatic chuck 5, so that the distance between the outlet of the gas supply pipeline 2 and the electrostatic chuck 5 is shortened, the stroke of free radicals is reduced, and the etching efficiency is improved.

As an implementation mode, a buffer plate 11 is arranged in the etching chamber 1, a plurality of through holes are formed in the buffer plate 11, and the free radicals pass through the through holes and reach the surface of the piece to be etched. Through setting up buffer board 11, can provide the cushioning effect for the diffusion in-process of free radical, make the concentration of free radical more even, prevent to lead to the sculpture inequality because of local concentration is too big.

Specifically, the buffer plate 11 is made of quartz to prevent a reaction between the buffer plate 11 and radicals.

In one embodiment, in order to protect the circuits of the first electrode 3 and the second electrode 4, avoid impurities from being generated in the etching chamber 1, and prolong the service life of the circuits, the first electrode 3 and the second electrode 4 are respectively located outside the gas supply pipeline and are oppositely arranged.

In one embodiment, the radical generating unit further comprises a flow control valve for controlling the gas flow of the gas source. The gas flow is controlled by arranging the flow control valve, so that the concentration of the free radicals can be controlled, the etching speed of the silicon carbide wafer is further controlled, and the etching process is more controllable.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A chemical dry etching apparatus, comprising:

the etching cavity is communicated with an outlet of the air supply pipeline, an electrostatic chuck for placing a piece to be etched is arranged in the etching cavity, a rotating assembly is arranged below the electrostatic chuck and used for driving the electrostatic chuck to rotate so as to drive the piece to be etched to rotate, and the free radicals enter the etching cavity through the air supply pipeline so as to etch the piece to be etched;

2. The chemical dry etching device according to claim 1, wherein the rotating assembly comprises a power mechanism and a connecting shaft, one end of the connecting shaft is connected with the power mechanism, the other end of the connecting shaft is connected with the electrostatic chuck,

3. The chemical dry etching apparatus according to claim 2, wherein the bottom wall of the etching chamber is provided with an installation opening, the rotating assembly further comprises a sealing plate and a supporting plate, the supporting plate is clamped at the installation opening, the supporting plate and the sealing plate are arranged in a matching manner to form a cavity structure, the power mechanism is arranged in the cavity structure,

4. The chemical dry etching device according to claim 3, wherein the etching chamber has a mounting opening formed in a side wall thereof, the rotating assembly further comprises a sealing plate and a supporting plate, the supporting plate is engaged with the mounting opening, the supporting plate and the sealing plate are cooperatively disposed to form a cavity structure, the power mechanism is disposed in the cavity structure, the sealing plate is connected to the electrostatic chuck,

5. The chemical dry etching apparatus according to claim 4, wherein the upper surface of the sealing plate is a horizontal surface.

6. The chemical dry etching apparatus according to any one of claims 1 to 5, wherein the outlet of the gas supply line is disposed above and opposite to the electrostatic chuck.

7. The chemical dry etching device according to any one of claims 1 to 5, wherein a buffer plate is disposed in the etching chamber, the buffer plate is provided with a plurality of through holes, and the radicals pass through the through holes and reach the surface of the to-be-etched member.

8. The chemical dry etching apparatus according to claim 7, wherein the gas supply line and/or the buffer plate is made of quartz.

9. The chemical dry etching apparatus according to any one of claims 1 to 4, wherein the first electrode and the second electrode are respectively located outside the gas supply line and are oppositely disposed.

10. The chemical dry etching apparatus according to any one of claims 1 to 4, wherein the radical generation unit further comprises a flow control valve for controlling a gas flow of the gas source.