KR101397414B1 - Plasma process equipment for etching wafer backside - Google Patents

Abstract

The present invention relates to a plasma processing apparatus for wafer backside etch which enlarges or reduces a wafer backside etch region in accordance with alteration of an isolation ring

A plasma processing apparatus for wafer backside etch for variable control of a wafer backside etch area in accordance with a type of process for etching a wafer backside surface or preventing a wafer backside surface from etching, A wafer chuck to which a wafer to be etched by the plasma is fixed; and a plurality of wafers which are provided on the side of the wafer chuck, An isolation ring capable of changing a backside etch area; a reaction gas supply unit provided on a side surface of the isolation ring for supplying a reaction gas supplied through the gas distribution plate to etch an edge portion of the wafer and a backside surface of the wafer, The upper And a lower electrode that interacts with the electrodes to form a predetermined electric field.

The present invention modifies the shape of the isolation ring by changing the shape of the isolation ring in accordance with the type of the process of etching the wafer backside surface or preventing the wafer backside surface from being etched. Therefore, a separate plasma processing apparatus The manufacturing process can be performed by replacing only the isolation ring with the conventional plasma apparatus without manufacturing.

Gas distribution plate, upper electrode, lower electrode, wafer backside etch area variable,

Description

[0001] Plasma processing apparatus for wafer backside etching [0002]

Field of the Invention [0002] The present invention relates to a semiconductor manufacturing apparatus for bevel etching, and more particularly, to a plasma processing apparatus for wafer backside etching that enlarges or reduces a wafer backside etching region in accordance with a change of an isolation ring.

Generally, a wafer for manufacturing a semiconductor device is repeatedly subjected to processes such as cleaning, diffusion, photoresist coating, exposure, development, etching, and ion implantation. The semiconductor manufacturing process is a process in which oxidation, masking, Various processes such as photoresist coating, etching, diffusion and laminating processes and auxiliary, washing, drying and inspection must be performed before and after these processes. In particular, the etching process is one of the important processes for forming a pattern on a wafer. The etching process is a photolithography process together with a photoresist coating process. The photoresist having a photosensitive property is coated on a wafer, , And etching is performed in accordance with the pattern to give appropriate physical characteristics of the device according to the pattern.

In order to manufacture a semiconductor device, a thin film is formed on the entire surface of the substrate when depositing a thin film, and a thin film is used as an etching target in the center of the substrate during etching. Therefore, the thin film remains on the edge of the substrate, Particles are deposited on the edge of the substrate during the process. In addition, since the substrate is normally placed on the substrate support supporting the substrate by the electrostatic force or the vacuum force, the interface between the substrate and the substrate support is spaced by a predetermined distance to generate a gap, And a thin film are deposited.

Therefore, when a continuous process is performed without removing the particles and the deposited thin film existing on the substrate, many problems such as warping of the substrate and difficulty in alignment of the substrate occur.

Generally, wet etching for removing particles on the surface by dipping in a solvent or rinse, and dry etching for removing the surface by plasma are widely known as methods for removing the particles and the deposited thin film as described above.

Wet etching is effectively used to remove particles applied to the surface of a substrate, but it is difficult to remove the substrate only locally due to difficulty in process control. In addition, there are problems such as a problem of cost increase due to use of a large chemical agent, Which causes environmental problems, requires long processing time, and requires a large-sized equipment.

On the other hand, the dry etching has an advantage of solving the above-mentioned problems of wet etching by removing thin films or particles on the substrate and the back surface by using plasma.

Therefore, in recent years, development of a dry etching apparatus for etching a backside of such a substrate has been actively carried out. That is, a conventional plasma etching apparatus for etching the rear surface of a substrate using the above-described plasma is disclosed in U.S. Patent No. 5,213,650.

The above-mentioned U.S. Patent No. 5,213,650 discloses an apparatus including a vacuum chamber for forming a space between a plate and a front surface of a wafer to inject reaction gas into the space, and for generating plasma on the wafer rear surface to perform etching Lt; / RTI >

When a thin film is deposited on a wafer, a thin film is deposited unevenly on the edge of the wafer, and this portion acts as a particle source later. Therefore, in order to solve this problem, a bevel etching (BEVEL ETCH).

1 is a configuration diagram of a conventional plasma processing apparatus for wafer backside etching.

An upper electrode 10 to which a reactive gas supply hole is formed to supply a reactive gas and to which a high frequency power is supplied so that a plasma can be generated;

A gas distribution plate 12 for uniformly supplying a reaction gas supplied from the outside to the inside,

A wafer chuck 14 to which the wafer 20 to be etched by the plasma is fixed,

An isolation ring 16 provided on a side surface of the wafer chuck 14 for shielding a high frequency power source excited by the wafer chuck 14,

The reaction gas supplied through the gas distribution plate 12 for etching the edge portion of the wafer 20 and the backside surface of the wafer 20, which is provided on the side surface of the isolation ring 16, And a lower electrode 18 which interacts with the electrode 10 to form a predetermined electric field.

First, when the wafer 20 is placed on the wafer chuck 14, the process gas is introduced into the process chamber 100 through the gas distribution plate 12 and the vacuum pressure is adjusted.

When the first RF power source is applied to the lower electrode 18 and the second RF power source is applied to the upper electrode 10, the electrons of the process gas are excited to increase the density of the ions, 10 and the lower electrode 18, as shown in FIG.

When the plasma region is formed, the density of the plasma is measured using a plasma measuring apparatus to control the flow rate of the process gas and the pressure inside the process chamber 100 to form a constant plasma density.

The ions in the plasma region are then directed to the surface of the wafer 20 on the wafer chuck 14 by a first high frequency power source applied to the lower electrode 18 to etch the film.

And the backside surface of the bevel region of the wafer 20 placed on the wafer chuck 14 is etched by the plasma gas formed between the upper electrode 10 and the lower electrode 18. [

In the conventional plasma processing apparatus as described above, when the wafer backside face is to be etched more widely or when the wafer backside face is not to be etched, the wafer backside face is uniformly etched, so that it can not adapt to the type of the process, It is necessary to manufacture a separate plasma processing apparatus for the type of plasma processing apparatus, which requires a large manufacturing cost.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method and apparatus for wafer backside etch which can vary the wafer backside etch area in accordance with the type of process for etching the wafer backside surface or for not etching the wafer backside surface, And to provide a plasma processing apparatus.

Another object of the present invention is to reduce the manufacturing cost by modifying the shape of the isolation ring according to the type of process and adjusting the wafer backside etch region so that a conventional plasma etching apparatus can be used instead of a separate plasma etching apparatus for each type of process And to provide a plasma processing apparatus for wafer backside etching.

According to an aspect of the present invention, there is provided a plasma processing apparatus for wafer backside etching, including: an upper electrode to which a high frequency power is supplied so that plasma can be generated; A wafer chuck to which a wafer to be etched by the plasma is fixed; an isolation ring provided on a side of the wafer chuck and capable of changing a backside etch region of the wafer; And a lower electrode which interacts with the upper electrode to form a predetermined electric field so that a reaction gas supplied through the gas distribution plate is etched to etch an edge portion of the wafer and a backside surface of the wafer, .

According to another aspect of the present invention, there is provided a plasma processing apparatus for etching a wafer backside, including: an upper electrode to which a high-frequency power is supplied so that plasma can be generated; A wafer chuck to which a wafer to be etched by the plasma is fixed; an isolation ring provided on a side surface of the wafer chuck and having an upper surface formed with an outward stepped portion for expanding a backside etch region of the wafer; A plurality of upper electrodes disposed on a side surface of the isolation ring for interacting with the upper electrode so as to convert the reaction gas supplied through the gas distribution plate to etch the edge portions of the wafer and the backside surface of the wafer, The lower electrode forming the electric field Characterized by configured.

And the isolation ring opens to expose the edge backside surface of the wafer to the plasma.

According to another aspect of the present invention, there is provided a plasma processing apparatus for etching a wafer backside, comprising: an upper electrode to which a high frequency power source is supplied so that plasma can be generated; A wafer chuck on which a wafer to be etched by the plasma is fixed; a gas supply part provided on a side surface of the wafer chuck so that the upper surface protrudes outward to shield the backside surface of the wafer from being etched; And a reaction gas supplied through the gas distribution plate to etch an edge portion of the wafer and a backside surface of the wafer is provided on a side surface of the isolation ring so as to be converted into a plasma state, Interaction with the electrodes And it characterized in that it comprises a lower electrode to form a predetermined electric field.

The protrusion covers an upper portion of the lower electrode so that the edge side surface of the wafer is not exposed to the plasma.

As described above, according to the present invention, the shape of the isolation ring is modified in accordance with the type of the process of etching the wafer backside surface or not etching the wafer backside surface, thereby varying the wafer etching region. Therefore, There is an advantage that the manufacturing process can be reduced because the process can be performed with the conventional plasma apparatus by replacing only the isolation ring without manufacturing the plasma processing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a configuration diagram of a plasma processing apparatus for wafer backside etching according to an embodiment of the present invention.

An upper electrode 30 to which a reactive gas supply hole is formed to supply a reactive gas and to which a high frequency power is supplied so that a plasma can be generated;

A gas distribution plate 32 for uniformly supplying a reaction gas supplied from the outside to the inside,

A wafer chuck 34 to which the wafer 40 to be etched by the plasma is fixed,

An upper surface of the wafer chuck 34 is provided with a stepped portion on the side of the wafer chuck 34 so as to extend the backside etch region of the wafer 40 and an isolation for shielding a high frequency power source excited by the wafer chuck 34 Ring 36,

The gas distribution plate 32 is provided on the side surface of the isolation ring 36 so that the reaction gas supplied through the gas distribution plate 32 is etched to etch the edge portion of the wafer 40 and the backside surface of the wafer 40, And a lower electrode 38 that interacts with the electrode 30 to form a predetermined electric field.

3A is a photograph before the backside surface of the wafer is etched,

FIG. 3B is a photograph of a state in which a backside surface of a wafer is etched by the plasma processing apparatus of FIG. 1,

3C is a photograph of etching the backside surface of the wafer by expanding the etching region applied to the present invention.

4 is an SEM photograph of an etched state at two points (A, B) of the edge of the wafer etched by the expansion of the plasma etching region according to an embodiment of the present invention.

FIG. 5 is a graph of etching distances of the wafers etched using the conventional plasma processing apparatus of FIG. 1 and the plasma processing apparatus of FIG. 2 according to the present invention.

A preferred embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5. FIG.

First, when the wafer 40 is placed on the wafer chuck 34, the process gas is introduced into the process chamber 200 through the gas distribution plate 32 and the vacuum pressure is adjusted.

When the first RF power source is applied to the lower electrode 38 and the second RF power source is applied to the upper electrode 30, the electrons of the process gas are excited to increase the density of the ions, 30 and the lower electrode 38. As shown in FIG.

When the plasma region is formed, the density of the plasma is measured by a plasma measuring apparatus to control the flow rate of the process gas and the pressure inside the process chamber 100 to form a constant plasma density.

The ions in the plasma region are then directed to the surface of the wafer 40 on the wafer chuck 34 by a first high frequency power source applied to the lower electrode 38 to etch the film applied to the wafer 40.

And the backside surface of the bevel region of the wafer 40 placed on the wafer chuck 34 is etched by the plasma gas formed between the upper electrode 30 and the lower electrode 38. At this time, the upper portion of the isolation ring 36 is stepped outward by a predetermined depth, and the etched region of the backside surface of the wafer 40 is expanded and etched. At this time, the isolation ring 36 functions to open the side surface of the wafer 40 so that the side surface of the wafer 40 is exposed to the plasma formed between the upper electrode 30 and the lower electrode 38.

3A is a photograph before the backside surface of the wafer 40 is etched, and FIG. 3B is a photograph of the state in which the backside surface of the wafer 40 is etched by the plasma processing apparatus of FIG.

3C shows a photograph of etching the backside surface of the wafer 40 by expanding the etching region by forming the stepped portion on the outer side of the isolation ring 40 applied to the present invention. The etching area of the back surface of the wafer 40 is 3.5 mm and is etched by 3.42 to 3.43 mm as shown in the SEM photograph of the etched state with respect to the two points A and B of the edge of the wafer 40, Can be recognized.

FIG. 5 is a graph of etching distances of the wafers etched using the conventional plasma processing apparatus of FIG. 1 and the plasma processing apparatus of FIG. 2 according to the present invention.

In FIG. 5, when the wafer 40 is etched by exposing the backside surface etching region of the wafer 40 according to the present invention, the wafer 40 is etched at about 3.0 to 3.43 mm,

5, P2 is etched at about 1.3 to 1.5 mm when the wafer is etched by the conventional plasma etching apparatus as shown in FIG.

P3 in FIG. 5 represents the wafer 40 divided by 8 equal parts when the front surface of the wafer 40 is etched and is etched at about 0.6 to 0.8 mm.

6 is a configuration diagram of a plasma processing apparatus for wafer backside etching according to another embodiment of the present invention.

An upper electrode 50 to which a high-frequency power source is supplied so that a reaction gas supply hole is formed and a plasma can be generated so that a reaction gas can be supplied,

A gas distribution plate 52 for uniformly supplying a reaction gas supplied from the outside to the inside,

A wafer chuck 54 to which the wafer 60 to be etched by the plasma is fixed,

The upper surface of the wafer chuck 54 is protruded outwardly so as to shield the backside of the wafer 60 from being etched. The upper surface of the wafer chuck 54 shields the high frequency power excited by the wafer chuck 54 An isolation ring 56,

The reaction gas supplied through the gas distribution plate 52 for etching the edge portion of the wafer 60 and the backside surface of the wafer 60 is provided on the side surface of the isolation ring 56, And a lower electrode 58 which interacts with the electrode 50 to form a predetermined electric field.

FIG. 7 is a graph of etching distances of the wafers 60 etched using the plasma processing apparatus according to another embodiment of the present invention, according to positions of coordinate values of left and right center of the wafer.

A preferred embodiment of the present invention will be described in detail with reference to FIGS. 6 to 7. FIG.

First, when the wafer 60 is placed on the wafer chuck 54, the process gas is introduced into the process chamber 300 through the gas distribution plate 52 and the vacuum pressure is adjusted.

When the first RF power is applied to the lower electrode 58 and the second RF power is applied to the upper electrode 50, the electrons of the process gas are excited to increase the density of the ions, And the lower electrode 58. In this case,

When the plasma region is formed, the density of the plasma is measured by the plasma measuring apparatus to control the flow rate of the process gas and the pressure inside the process chamber 300 to form a constant plasma density.

The ions in the plasma region are then directed to the surface of the wafer 60 on the wafer chuck 54 by a first high frequency power source applied to the lower electrode 58 to etch the film applied to the wafer 60.

And the backside surface of the bevel region of the wafer 60 placed on the wafer chuck 54 is etched by the plasma gas formed between the upper electrode 50 and the lower electrode 58. At this time, the upper portion of the isolation ring 56 has a protruding portion 55 extending outwardly by a predetermined length. The length of the protrusion 55 is shorter than the outermost side end of the lower electrode 58. The projecting portion 55 of the isolation ring 56 covers the upper portion of the lower electrode 58 forming the plasma so that the backside face of the wafer 60 is not etched so that the ions of the plasma reach the backside of the wafer 60 It is shielded from being excited. The isolation ring 56 covers an upper portion of the lower electrode 58 so that the edge side surface of the wafer 60 is not exposed to the plasma.

When the etching is performed as described above, the backside surface of the wafer 60 is etched as shown in FIG. 7,

7 is a graph in which the front surface of the wafer 60 is etched,

7 is a graph in which the backside surface of the wafer 60 is etched.

7, etching is performed at the edge portion of the front surface of the wafer 60 in the center coordinates 148.005 to 149.205 from the center of the wafer 60 to the center of the right edge from the center of the wafer 60, The etching is done at coordinates 149.205 by 2754.165nm. Then, etching is performed at the edge portion of the backside of the wafer 60 in the range of -145.755 to -146.940 from the center of the left edge of the wafer 60. At the center of the wafer 60 at the center-146.940 Etching is performed at 3260.887 nm.

7, etching is performed at the edge portion of the backside of the wafer 60 in the center coordinates of 147.800 to 149.205 from the center of the wafer 60 to the right edge of the wafer 60, The etching is performed at coordinates 149.205 to 81.3678 nm. Then, etching is performed at the edge portion of the backside of the wafer 60 in the range of -145.755 to -146.940 from the center of the left edge of the wafer 60. At the center of the wafer 60 at the center-146.940 Etching is performed at 86.9752 nm.

6, when the plasma etching is performed after forming the projection 55 protruding outward from the isolation ring 56, as shown in the right graph of FIG. 7, the backside surface of the wafer 60 is hardly etched do.

As described above, according to the present invention, the backside surface of the wafer 40 is exposed to a large amount of plasma by using the isolation ring 36 as shown in FIG. 2, thereby increasing the etching range. By using the isolation ring 56, The backside surface of the wafer 60 is less exposed to the plasma so that the backside surface of the wafer 60 is not etched.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents. And such changes are, of course, within the scope of the claims.

1 is a schematic view of a conventional plasma processing apparatus for wafer backside etching

FIG. 2 is a configuration diagram of a plasma processing apparatus for wafer backside etching according to an embodiment of the present invention

3A is a photograph before the backside surface of the wafer is etched,

FIG. 3B is a photograph showing a state in which the backside surface of the wafer is etched by the plasma processing apparatus of FIG.

FIG. 3C is a photograph of the backside surface of the wafer being etched by expanding the etching region applied to the present invention. FIG.

4 is a SEM photograph of an etched state at two points (A, B) of the edge of the wafer etched by the expansion of the plasma etching region according to an embodiment of the present invention

FIG. 5 is a graph showing the etch distance of a wafer etched using the conventional plasma processing apparatus of FIG. 1 and the plasma processing apparatus of FIG. 2,

6 is a schematic view of a plasma processing apparatus for wafer backside etching according to another embodiment of the present invention

7 is a graph showing the etch distance of the wafer 60 etched using the plasma processing apparatus according to another embodiment of the present invention,

            Description of the Related Art [0002]

10: upper electrode 12: gas distribution plate

14: Wafer chuck 16: Isolation ring

18: lower electrode 20: wafer

Claims (5)

delete A plasma processing apparatus for wafer backside etching, An upper electrode to which a high frequency power is supplied so that a plasma can be generated, A gas distribution plate for uniformly supplying a reaction gas supplied from the outside to the inside, A wafer chuck to which a wafer to be etched by the plasma is fixed, An isolation ring provided on a side surface of the wafer chuck to form a stepped portion on an upper surface thereof so as to extend a backside etch region of the wafer, A plurality of upper electrodes disposed on a side surface of the isolation ring for interacting with the upper electrode so as to convert a reaction gas supplied through the gas distribution plate to etch the edge portion of the wafer and the backside surface of the wafer, And a lower electrode, Wherein the edge surface of the wafer is opened to expose the plasma so that the upper surface of the isolation ring does not contact the backside surface of the wafer. delete A plasma processing apparatus for wafer backside etching, An upper electrode to which a high frequency power is supplied so that a plasma can be generated, A gas distribution plate for uniformly supplying a reaction gas supplied from the outside to the inside, A wafer chuck to which a wafer to be etched by the plasma is fixed, An isolating ring provided on a side surface of the wafer chuck and integrally formed with a protrusion formed so that an upper surface protrudes outward to shield the backside surface of the wafer from being etched; And a reaction gas supplied through the gas distribution plate to etch an edge portion of the wafer and a backside surface of the wafer, which are provided on a side surface of the isolation ring, respectively interact with the upper electrode to convert a predetermined electric field And a lower electrode formed on the upper surface of the lower substrate. 5. The method of claim 4, Wherein the protrusion covers an upper portion of the lower electrode so that the edge backside surface of the wafer is not exposed to the plasma.

Images