SUSCEPTOR AND MANUFACTURING METHOD THEREFOR

Disclosed are a susceptor for enabling uniform plasma treatment over the entire surface of a wafer, and a manufacturing method therefor. Provided is the susceptor comprising: a dielectric plate having an upper surface on which a wafer is loaded, and a lower surface facing same; and an inner RF electrode and an outer RF electrode that are buried in the dielectric plate, wherein, with respect to the lower surface, the height of a first plane in which the inner RF electrode is buried is less than the height of a second plane in which the outer RF electrode is buried.

TECHNICAL FIELD

The present disclosure relates to a susceptor and a manufacturing method therefor, and relates to a susceptor capable of uniform plasma treatment over an entire surface of a wafer, and a manufacturing method therefor.

BACKGROUND ART

In a semiconductor device manufacturing process, various processes such as a film formation process, an etching process, or the like are performed on a semiconductor wafer, a process target. In a semiconductor manufacturing apparatus processing the semiconductor wafer, a susceptor for supporting the semiconductor wafer is used. In the susceptor, a conductor such as a radio frequency (RF) electrode, a clamping electrode, and/or a resistance heating element is formed within a body formed of a ceramic material such as aluminum nitride or on a surface of the substrate to function as a heater and/or an electrostatic chuck.

FIG.1is a schematic diagram illustrating an example of a susceptor according to the related art.

Referring toFIG.1, the susceptor1includes a plate10supporting a wafer. The plate10may be formed of a dielectric material such as aluminum nitride. RF electrodes12A and12B and a heating element14may be provided within the dielectric plate10.

FIG.1has an inner circular RF electrode12A positioned closer to a dielectric plate surface, and an outer annular RF electrode12B positioned farther from the plate surface. The circular RF electrode12A and the annular RF electrode12B are provided with terminals for power supply and lead wires16A,16B and16C. According to the structure ofFIG.1, the annular RF electrode12B is disposed below the circular RF electrode12A, thereby removing interference between terminals and rendering potential uniform in an RF electrode so as to suppress variations in plasma density.

However, in a multilayer susceptor according to the related art illustrated inFIG.1, the outer RF electrode is positioned below the inner RF electrode to apply power to the outer RF. Due to such a structural issue, configurations for designs and layers of the inner and outer RF electrodes are limited.

In particular, when a pocket-type susceptor is manufactured, plasma control is difficult because an upper dielectric thickness (UDT) of the inner RF electrode is different from an upper dielectric layer thickness (UDT) of the outer RF electrode. For example, in order to implement the same plasma density, it is necessary to take measures such as applying a frequency to each RF electrode.

In order to resolve such an issue, a susceptor having a design in which a loading surface of a wafer of the susceptor is designed to be high has been developed. However, the susceptor is limited to have a special design providing a step on the loading surface of the wafer. In addition, it is necessary to fasten an additional part to the outside of a ceramic heater in order to prevent wafer sliding.

SUMMARY OF INVENTION

Technical Problem

An aspect of the present disclosure is to provide a susceptor capable of uniform plasma control.

Another aspect of the present disclosure is to provide a susceptor improving deposition uniformity of a wafer by preventing edge lifting of the wafer caused by gas flow during a process.

Another aspect of the present disclosure is to provide a pocket-type susceptor having a multilayer RF electrode.

Another aspect of the present disclosure is to provide an electrode structure suitable for a structure of a pocket-type susceptor.

Another aspect of the present disclosure is to provide a method for manufacturing the above-described susceptor.

Solution to Problem

In order to achieve the above technical problem, the present disclosure provides a susceptor including a dielectric plate having an upper surface on which a wafer is loaded, and a lower surface opposite the upper surface, and an inner RF electrode and an outer RF electrode that are buried in the dielectric plate, wherein, with respect to the lower surface, a height of a first plane in which the inner RF electrode is buried is less than a height of a second plane in which the outer RF electrode is buried.

In the present disclosure, the upper surface includes a first surface on which a wafer is loaded and a second surface surrounding the first surface, and a height of the first surface may be lower than a height of the second surface with respect to the lower surface.

At this time, a first upper dielectric layer thickness (udt1) from the first plane to the first surface may be substantially the same as a second upper dielectric layer thickness (udt2) from the second plane to the second surface.

Conversely, a first upper dielectric layer thickness (udt1) from the first plane to the first surface and a second upper dielectric layer thickness (udt2) from the second plane to the second surface may satisfy a relationship of −0.5<(udt1-udt2)/udt1<0.5.

In the present disclosure, a ratio of an electrode gap (δ) defined as a difference between an inner circumference radius (r3) of the outer RF electrode and a radius (r1) of the inner RF electrode with respect to a radius (r1) of an inner electrode may satisfy a relationship of −0.9≤r3/r1≤1.0.

In the present disclosure, the inner RF electrode and the outer RF electrode are one of a sheet-type or a mesh-type.

In addition, the present disclosure may include a connection member for power supply to the outer RF electrode. At this time, the connection member is one of a sheet-type or a rod-type.

In addition, the susceptor according to the present disclosure may further include a heating element disposed within the plate. In addition thereto or aside therefrom, the susceptor according to the present disclosure may further include a clamping electrode disposed within the plate.

In the present disclosure, a height difference between the first plane and the second plane may be 0.1 to 2.0 mm.

Advantageous Effects of Invention

According to the present disclosure, there may be provided a susceptor capable of uniform plasma control.

In addition, according to the present disclosure, there may be provided a susceptor improving deposition uniformity of a wafer by preventing edge lifting of the wafer caused by gas flow during a process.

In addition, the present disclosure may provide a multilayer RF electrode structure suitable for a pocket-type susceptor.

BEST MODE FOR INVENTION

The Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings. In this case, it should be noted that the same components are denoted by the same reference numerals in the accompanying drawings. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted. For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings, and the size of each component does not fully reflect the actual size. Therefore, the contents described herein are not limited by the relative size or spacing of the components drawn in each drawing.

In addition, in the present disclosure, “stack” is used to define a relative positional relationship between respective layers. The description “layer B on layer A” indicates a relative positional relationship between layer A and layer B, and it is not required that layer A and layer B come into contact with each other, and a third layer may be interposed therebetween. Similarly, the description “layer C is interposed between layer A and layer B” does not exclude the case in which a third layer is interposed between layer A and layer C or between layer B and layer C.

FIGS.2A and2Bare a schematic cross-sectional view and a schematic plan view illustrating an electrode structure of a susceptor according to an example embodiment of the present disclosure.

Referring toFIGS.2A and2B, the susceptor100includes a plate110on which a pocket-type wafer loading surface116is formed. The plate110may be formed of a dielectric material such as AlN. The dielectric plate110has an upper surface, which is a side supporting a wafer, and a lower surface, which is an opposite side, facing the upper surface.

The upper surface has at least two surfaces including a loading surface116, which is a first surface on which a wafer is loaded, and an outer circumferential surface118, which is a second surface adjacent to the wafer loading surface and surrounding the wafer loading surface.

An inner RF electrode120A and an outer RF electrode120B are provided within the susceptor. In the present disclosure, the RF electrodes120A and120B are preferably buried in a dielectric plate, but is not necessarily limited thereto. In the present disclosure, the inner RF electrode and the outer RF electrode may be a mesh-type or sheet-type.

A connection member142and/or a lead140may be provided to supply power to the inner RF electrode120A. A connection member130and/or a lead132may be provided to supply power to the outer RF electrode120B. The connection member and the leads130and132may pass through the inside of the support member150to be connected to a power supply means.FIG.2Aillustrates one connection member130being formed on the outer RF electrode120B. However, a plurality of connection members may also be formed on the outer RF electrode120B.

In the present disclosure, the inner RF electrode120A may have a shape corresponding to a shape of a wafer or a wafer mounting surface. Preferably, the outer circumferential shape of the internal RF electrode120A is planarly circular. In addition, the inner RF electrode120A may have a cylindrical shape in general, but may be divided into a plurality of regions, and each divided segment may have an arc shape having a predetermined angle.

In the present disclosure, the outer RF electrode120B may planarly have an annular shape having a width of w. In the present disclosure, a width of the outer RF electrode120B is preferably a constant value along a circumference thereof, but is not limited thereto.

As illustrated inFIG.2B, the inner RF electrode and the outer RF electrode may be disposed to have a concentric structure. In addition, the drawing illustrates that the inner RF electrode and the outer RF electrode do not overlap on a plane, but the present disclosure is not limited thereto. Depending on required plasma distribution, the inner RF electrode and the outer RF electrode may be present on different planes in a plate, and thus may planarly overlap. Therefore, in the present disclosure, the descriptions “inner” and “outer” may be defined as sizes of outer radii (r1and r2) on concentric circles of respective electrodes.

In the present disclosure, a difference value between an inner circumferential radius (r3) of an outer electrode and a radius (r1) of an inner electrode may be defined as an electrode gap (δ). When the outer electrode and the inner electrode are not concentric circles, the electrode gap may be defined as an average value. In the present disclosure, the electrode gap may have a positive value or a negative value.

In the present disclosure, a ratio of the electrode gap (δ) to the radius (r1) of the inner electrode may be appropriately designed. When overlapping electrodes are allowed, the ratio may preferably have a value of 0.8≤r3/r1≤1.0, more preferably 0.9≤r3/r1≤1.0. When the electrodes do not overlap, the ratio may preferably have a value of 1<r3/r1<1.2, more preferably 1≤r3/r1<1.1. r1preferably does not exceed r2.

In the present disclosure, the inner RF electrode120A and the outer RF electrode120B are disposed on different planes. Specifically, a plane on which the outer RF electrode is disposed is higher than a plane on which the inner RF electrode is disposed by δh (δh>0). In the present disclosure, δh is preferably 0.1 to 2.0 mm.

A vertical arrangement relationship between the inner and outer RF electrodes may be defined as an upper dielectric layer thickness (udt), which refers to a distance from a plane on which the electrodes are positioned to a surface of the dielectric plate110thereon. A plane distance between a plane on which the inner RF electrode is disposed and the loading surface116may be represented by udt1, and a plane distance between a plane on which the outer RF electrode is disposed and the outer circumferential surface118is represented by udt2. In the present disclosure, a difference between udt1and udt2is limited to have a value within a predetermined range, and the difference between udt1and udt2is preferably close to zero. Preferably, udt1and udt2may satisfy a relationship of −1<(udt1-udt2)/udt1<1, −0.9<(udt1-udt2)/udt1<0.9, −0.8<(udt1-udt2)/udt1<0.8, −0.7<(udt1-udt2)/udt1<0.7, −0.6<(udt1-udt2)/udt1<0.6, −0.5<(udt1-udt2)/udt1<0.5, −0.4<(udt1-udt2)/udt1<0.4, −0.3<(udt1-udt2)/udt1<0.3, −0.2<(udt1-udt2)/udt1<0.2, or −0.1<(udt1-udt2)/udt1<0.1.

As such, the upper dielectric layer thickness may have substantially the same value, thereby allowing plasma to be uniformly distributed on the outer circumferential surface. Such uniform plasma distribution provides various advantages. For example, it is possible to provide an advantage of uniform film formation in the vicinity of a wafer edge on a susceptor.

Although not additionally described, the susceptor according to the present disclosure may further include a heating element and/or a clamping electrode disposed within a plate. The heating element and the clamping electrode may be disposed in an appropriate position above or below the RF electrode.

Mode for Invention

Hereinafter, a method for implementing a susceptor according to an example embodiment of the present disclosure will be described with reference to the drawings.

Various methods may be applied to form two RF electrodes present on different planes. As an example,FIGS.3and4are diagrams illustrating a process of manufacturing a susceptor using pre-sintering.

FIG.3is a schematic diagram illustrating a cross section of a pre-sintered susceptor precursor200, andFIG.4is a schematic diagram illustrating a cross section of the susceptor precursor200in a state in which a molded body is stacked on a pre-sintered body.

Referring toFIG.3, the susceptor precursor200has a structure in which a lower pre-sintered body212A and an upper pre-sintered body212B are stacked. An inner RF electrode220A is formed on the lower pre-sintered body212A, and an outer RF electrode220B is formed on the upper pre-sintered body220B. Electrode connection members230A and240A for power supply are provided on the inner RF electrode and the outer RF electrode. There is an advantage in that the susceptor precursor200may adjust a height of an RF electrode by a thickness of the pre-sintered body.

FIG.4illustrates a state in which molded bodies213and214are stacked on an upper portion and a lower portion of the stacked pre-sintered bodies212A and212B ofFIG.3. A portion or all of the molded bodies213and214may also be replaced with molded powder. As illustrated inFIG.4, raw material powder in a stacked state may be manufactured into a sintered body through a sintering process such as a hot press process, and finally the susceptor illustrated inFIGS.2A and2Bmay be manufactured through a subsequent processing process.

Although securing a distance between electrodes using a multilayer or multistage pre-sintered body is described above with reference toFIGS.3and4, the present disclosure may be implemented in other manners.

Referring toFIGS.5and6, a manufacturing process according to another example embodiment of the present disclosure will be described.FIG.5is a schematic diagram illustrating a cross section of the pre-sintered susceptor precursor200, andFIG.6is a schematic diagram illustrating a cross section of the susceptor precursor200in a state in which a molded body is stacked on a pre-sintered body. UnlikeFIG.3, the susceptor precursor200ofFIG.5includes a single pre-sintered body212C. An inner RF electrode is buried in the single pre-sintered body212C, and an outer RF electrode is installed on an upper portion of the single pre-sintered body212C. In addition, connection members230B and240B for applying power to the RF electrodes may be provided. The terminals may be manufactured by various manners, such as a process of inserting a terminal formed of a metal material after processing the pre-sintered body, or by a process of burying a connection member formed of a metal material before manufacturing the pre-sintered body, and then performing a pre-sintering.

Subsequently, as illustrated inFIG.6, the susceptor may be manufactured by stacking molded bodies (or molded body powders)213and214on the upper portion and lower portion of the pre-sintered body212C, and then performing a hot press process.

FIGS.7A to7Eare diagrams specifically illustrating an example of a process of manufacturing a stacked pre-sintered body ofFIG.3according to an example embodiment of the present disclosure.

First, referring toFIG.7A, the lower pre-sintered body212A is provided. The lower pre-sintered body212A has a plurality of stepped surface structures213,215, and217. A central groove217corresponds to a position in which an inner RF electrode is formed, and an outermost groove213and an intermediate groove215act as a fixing frame for stacking an upper pre-sintered body.

The above-described stepped surface structures213,215, and217may be obtained by performing surface-processing on a pre-sintered body in an appropriate manner. A hole232for a connection member for an RF electrode is provided in the lower pre-sintered body212A. Although not illustrated, a hole for a connection member for an inner RF electrode may be provided.

Subsequently, as illustrated inFIG.7B, an inner RF electrode is formed in the central groove217. Various methods such as a method of disposing a metal electrode processed along a shape of the central groove217, a printing method such as screen printing using a slurry of conductive metal particles, and the like may be applied for the formation of the inner RF electrode.

Subsequently, as illustrated inFIG.7C, the upper pre-sintered body212B is stacked on the lower pre-sintered body212A. The upper pre-sintered body212B has a groove218corresponding to a position in which an outer RF electrode is formed. In addition, in the pre-sintered body212B, a hole232is formed to extend for a connection member for an outer RF electrode. The above-described method of forming the hole232for the connection member for an outer RF electrode is exemplary. The hole232for the connection member may be formed after the upper and lower pre-sintered bodies are stacked.

Subsequently, as illustrated inFIG.7D, a connection member230is formed by inserting, into the hole232for an outer RF electrode, a metal member processed to have a “C” shape. At this time, the connection member230may be in the form of a thin and long plate processed to have a “C” shape or a rod having a circular or polygonal cross section. The connection member230is inserted into the hole232for the electrode, and then is bent in the groove218for forming an outer RF electrode.

Subsequently, as illustrated inFIG.7E, the outer RF electrode may be formed by disposing a processed metal electrode in the hole232for the electrode or by a printing method such as screen printing using a slurry of conductive metal particles, thereby preparing a susceptor precursor, as illustrated inFIG.3.

Examples

Table 1 is a table showing specifications of and film formation results of RF electrodes when udts of the RF electrodes are the same, and Table 2 is a table showing specifications and film formation results of the RF electrodes when the udts of the RF electrodes are different from each other.

While the present disclosure has been described in conjunction with specific details, such as specific components, and limited example embodiments and drawings above, the example embodiments and drawings are provided merely to help an overall understanding of the present disclosure. The present disclosure is not limited to the above-described example embodiments, and various modifications and alterations can be made based on the foregoing description by those skilled in the art to which the present disclosure pertains. Therefore, the technical spirit of the present disclosure should not be determined based only on the described example embodiments, and the following claims, all equivalents to the claims and equivalent modifications should be construed as falling within the scope of the spirit of the present disclosure.

Industrial Applicability

The present disclosure is usable for a ceramic heater and/or a susceptor such as an electrostatic chuck used for manufacturing a semiconductor or the like.