JP7828782B2 - Sample holder - Google Patents

Description

The embodiments of the disclosure relate to a sample holder.

In the semiconductor component manufacturing process, electrostatic chucks are used as sample holders to hold the workpiece, such as semiconductor wafers, that are to be subjected to plasma treatment. These electrostatic chucks are constructed, for example, by bonding a ceramic substrate with embedded electrodes to a metal base plate.

This electrostatic chuck has a channel formed for supplying a heat transfer gas for temperature control to the workpiece placed on the electrostatic chuck. Furthermore, from the viewpoint of suppressing plasma intrusion into the channel, an electrostatic chuck with a porous body placed within the channel has been proposed (see, for example, Patent Document 1).

Japanese Patent Publication No. 2019-165223

However, the conventional technology described above still had room for further improvement in suppressing abnormal discharge in the flow path.

One embodiment, made in view of the above, aims to provide a sample holder that can suppress abnormal discharge in the flow path.

A sample holder according to one embodiment comprises a ceramic substrate, a base plate, and an embedded member. The ceramic substrate has a first surface on which the object to be processed is placed, a second surface located opposite the first surface, and a first channel penetrating between the first and second surfaces. The base plate is bonded to the second surface of the ceramic substrate and has a through hole at least at a position corresponding to the first channel. The embedded member has a porous body at its end on the first channel side within the through hole, and a second channel communicating with the first channel via the porous body. Furthermore, the second channel has a first portion perpendicular to the first surface and a second portion intersecting the first portion.

According to one embodiment, a sample holder capable of suppressing abnormal discharge in the flow path can be provided.

Figure 1 is a perspective view showing the configuration of a sample holder according to an embodiment. Figure 2 is a schematic diagram showing a cross-section of the sample holder according to the embodiment. Figure 3 is an enlarged cross-sectional view showing the configuration of the embedded member and its surrounding area according to the embodiment. Figure 4 is a plan view showing an example of the configuration of the embedded member according to the embodiment, viewed from above. Figure 5 is an enlarged cross-sectional view showing the configuration of the embedded member and its surrounding area according to a modified example 1 of the embodiment. Figure 6 is a plan view showing an example of the configuration of the embedded member according to the modified embodiment 1, as viewed from above. Figure 7 is an enlarged cross-sectional view showing the configuration of the embedded member and its surroundings according to a modified example 2 of the embodiment. Figure 8 is a plan view showing an example of the configuration of the embedded member according to the modified embodiment 2, as viewed from above. Figure 9 is an enlarged cross-sectional view showing the configuration of the embedded member and its surroundings according to a modified example 3 of the embodiment. Figure 10 is a plan view showing an example of the configuration of the embedded member according to the modified embodiment 3, viewed from above. Figure 11 is an enlarged cross-sectional view showing the configuration of the embedded member and its surroundings according to a modified example 4 of the embodiment. Figure 12 is a plan view showing an example of the configuration of the embedded member according to the modified embodiment 4, viewed from above. Figure 13 is an enlarged cross-sectional view showing the configuration of the embedded member and its surrounding area according to a modified example 5 of the embodiment. Figure 14 is a plan view showing an example of the configuration of the embedded member according to modified embodiment 5, viewed from above.

The embodiments of the sample holder disclosed in this application will be described below with reference to the attached drawings. However, this invention is not limited to the embodiments shown below. Furthermore, each embodiment can be combined as appropriate, provided that the content is not contradictory. Also, the same parts are denoted by the same reference numerals in each of the following embodiments, and redundant descriptions are omitted.

Furthermore, in the embodiments described below, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not require strict adherence to "constant," "orthogonal," "perpendicular," or "parallel" conditions. For example, "perpendicular" means that the central axis of the first part is 90° ± 2° relative to the first surface, while "parallel" means that the central axis of the second part is 0° ± 2° relative to the first surface. In other words, each of the above expressions allows for deviations such as manufacturing accuracy or installation accuracy.

<Implementation>
First, the configuration of the sample holder 100 according to the embodiment will be described with reference to Figures 1 to 4. Figure 1 is a perspective view showing the configuration of the sample holder 100 according to the embodiment. As shown in Figure 1, the sample holder 100 has a structure in which a ceramic substrate 110 and a base plate 120 are joined together.

The ceramic substrate 110 uses electrostatic force to attract a workpiece (not shown), such as a semiconductor wafer. The ceramic substrate 110 is a component formed from a ceramic-containing raw material into a roughly disc-shaped form.

The ceramic substrate 110 mainly contains aluminum oxide ( _Al₂O₃ ), aluminum _nitride (AlN), _yttria ( _Y₂O₃ ), cordierite, silicon carbide (SiC), and silicon _nitride ( _Si₃N₄ ).

The base plate 120 is a support member that supports the ceramic substrate 110. The base plate 120 is attached, for example, to semiconductor manufacturing equipment, and allows the sample holder 100 to function as a semiconductor holding device for holding a workpiece such as a semiconductor wafer.

The base plate 120 is a circular metal component. As the metal material forming the base plate 120, for example, aluminum, stainless steel, titanium, or aluminum matrix composite materials such as AlSiC can be used.

Figure 2 is a schematic diagram showing a cross-section of the sample holder 100 according to the embodiment. As described above, the sample holder 100 is constructed by joining a ceramic substrate 110 and a base plate 120.

The ceramic substrate 110 has a first surface 110a and a second surface 110b. A workpiece (not shown), such as a semiconductor wafer, is placed on the first surface 110a. The second surface 110b is located on the opposite side from the first surface 110a.

The object to be treated, placed on the first surface 110a of the ceramic substrate 110, is subjected to plasma treatment by generating plasma above the first surface 110a. This plasma can be generated by applying high-frequency power to an electrode (not shown) facing the first surface 110a to excite a gas.

An electrode 111 is positioned inside the ceramic substrate 110. This electrode 111 is, for example, an electrostatic adsorption electrode, and is a conductive material containing a metal such as platinum, tungsten, or molybdenum. In the sample holder 100, when a voltage is applied to the electrode 111, an electrostatic force is generated, and acting as an electrostatic chuck, this electrostatic force adsorbs the object to be processed onto the first surface 110a of the ceramic substrate 110.

The base plate 120 is bonded to the second surface 110b of the ceramic substrate 110. The base plate 120 may be bonded to the second surface 110b via, for example, a bonding material. Such a bonding material could be, for example, an adhesive such as silicone resin.

The base plate 120 may have an internal space 121. This space 121 may be used, for example, as a refrigerant passage for a cooling medium such as cooling water or cooling gas. Furthermore, the base plate 120 may also function as a high-frequency electrode to which high-frequency power for plasma generation is applied.

As shown in Figure 2, a first channel 112 is formed in the ceramic substrate 110, penetrating between the first surface 110a and the second surface 110b.

Furthermore, through-holes 122 are formed in the base plate 120 at positions corresponding to at least the first flow path 112. The embedded member 130 is then placed within these through-holes 122.

The embedded member 130 is a cylindrical member made of _an insulating material such as aluminum oxide ( _Al₂O₃ ). If a recess 113 is provided on the second surface 110b of the ceramic substrate 110, the embedded member 130 may protrude toward the ceramic substrate 110 side from the upper surface of the base plate 120 (i.e., the surface joined to the second surface 110b) and be fitted into the recess 113.

As a result, the length of the first channel 112 is shortened at the position corresponding to the recess 113 in the ceramic substrate 110, thereby suppressing the generation of plasma within the first channel 112.

The embedded member 130 has a porous body 131 at the end facing the first channel 112. By positioning the porous body 131 at the end facing the first channel 112, the problem of plasma passing through the first channel 112 and reaching the base plate 120 when plasma is generated above the first surface 110a of the ceramic substrate 110 can be reduced.

The porous body 131 is, for example, an alumina porous body or other ceramic porous body. The porous body 131 only needs to have enough voids to allow gas flow. The porosity of the porous body 131 is, for example, 40% to 60%.

Furthermore, the embedded member 130 has a second channel 132 that communicates with the first channel 112 via the porous body 131. The second channel 132 and the first channel 112 form a continuous gas channel from the lower surface of the base plate 120 through the porous body 131 to the upper surface (first surface 110a) of the ceramic substrate 110.

For example, a heat transfer gas such as helium may be flowed through the second channel 132 and the first channel 112. By flowing a heat transfer gas through the second channel 132 and the first channel 112, the heat transfer gas is supplied to the back surface of the workpiece placed on the first surface 110a of the ceramic substrate 110, thereby improving the heat transfer coefficient between the workpiece and the ceramic substrate 110.

Figure 3 is an enlarged cross-sectional view showing the configuration of the embedded member 130 and its surroundings according to the embodiment, and Figure 4 is a plan view showing an example of the configuration of the embedded member 130 according to the embodiment as seen from above. Note that Figure 4 and the subsequent drawings corresponding to Figure 4 also show the position of the first channel 112 formed in the ceramic substrate 110 (see Figure 3) for ease of understanding.

As shown in Figure 3 and other figures, in this embodiment, the second channel 132 formed in the embedded member 130 has a first portion 132a and a second portion 132b. The first portion 132a is a portion perpendicular to the first surface 110a of the ceramic substrate 110.

The second portion 132b is the portion that intersects with the first portion 132a. In other words, the second portion 132b is the portion that extends in a different direction from the first portion 132a. For example, in this embodiment, the second portion 132b is parallel to the first surface 110a and is linear.

Furthermore, in this embodiment, a second channel 132 is formed by connecting two first portions 132a with a single second portion 132b. As a result, the second channel 132 has a bent shape within the embedded member 130.

Of the two first portions 132a, the first portion 132a directly connected to the porous body 131 is positioned to overlap with the first channel 112 in a plan view, as shown in Figure 4. On the other hand, the first portion 132a not directly connected to the porous body 131 is positioned so as not to overlap with the first channel 112 in a plan view.

For example, let's assume that the first channel 112 and the second channel 132 are located in a straight line from the upper surface (first surface 110a) of the ceramic substrate 110 to the lower surface of the base plate 120.

In this case, when plasma is generated above the first surface 110a, charged particles in the plasma may enter the first channel 112 while maintaining high energy, reaching the porous body 131 and the second channel 132. This could lead to abnormal discharges occurring in the porous body 131 and the second channel 132.

In contrast, in this embodiment, as shown in Figure 3 and other figures, the second channel 132 has a bent structure, i.e., a labyrinth structure. This allows charged particles in the plasma to enter the first channel 112 when plasma is generated above the first surface 110a, and these charged particles can be deactivated by colliding them with the wall of the second channel 132.

Furthermore, in this embodiment, the overall length of the channels can be increased compared to the case where the first channel 112 and the second channel 132 are located in a straight line from the first surface 110a of the ceramic substrate 110 to the lower surface of the base plate 120.

This allows charged particles in plasma generated above the first surface 110a to be deactivated midway through the long channel 112, even if they enter the first channel 112.

As explained above, in this embodiment, the second channel 132 has a bent structure, which allows charged particles entering the second channel 132 to be easily deactivated, thereby suppressing the occurrence of abnormal discharges in the first channel 112 and the second channel 132.

The embedded member 130 according to this embodiment can be formed, for example, by laminating a cylindrical green sheet with a through hole corresponding to the first portion 132a and a cylindrical green sheet with a lateral hole corresponding to the second portion 132b to form a laminate, and then firing this laminate.

Furthermore, in this embodiment, by arranging the second portion 132b parallel to the first surface 110a, a green sheet with a corresponding lateral hole can be easily formed, thus allowing for the easy formation of the embedded member 130.

Furthermore, the embedded member 130 according to this embodiment may be formed by arranging two semi-cylindrical molded bodies, each having a first portion 132a and a second portion 132b formed in a semi-cylindrical shape, pressing them together to form a cylindrical shape, and then firing the pressed molded bodies.

Furthermore, the embedded member 130 according to this embodiment may be formed by creating a cylindrical molded body with the first portion 132a and the second portion 132b formed inside using a 3D printer, and then firing the molded body.

<Variation 1>
Next, various modifications of the embodiment will be described with reference to Figures 5 to 14. Figure 5 is an enlarged cross-sectional view showing the configuration of the embedded member 130 and its surroundings according to Modification 1 of the embodiment, and Figure 6 is a plan view showing an example of the configuration of the embedded member 130 according to Modification 1 of the embodiment as seen from above.

As shown in Figure 5 and other figures, the sample holder 100 according to Modification 1 has a different configuration of the second channel 132 compared to the embodiment described above. Specifically, in Modification 1, the second portion 132b of the second channel 132 is positioned at an angle to the first portion 132a and the first surface 110a.

This also allows charged particles in plasma generated above the first surface 110a to enter the first channel 112, causing them to collide with the wall of the second channel 132 and be deactivated.

Furthermore, in Modification 1, even if charged particles in the plasma enter the first channel 112, they can be deactivated along the long channel. Therefore, according to Modification 1, the occurrence of abnormal discharges in the first channel 112 and the second channel 132 can be suppressed.

<Modified Example 2>
Figure 7 is an enlarged cross-sectional view showing the configuration of the embedded member 130 and its surroundings according to Modification 2 of the Embodiment, and Figure 8 is a plan view showing an example of the configuration of the embedded member 130 according to Modification 2 of the Embodiment as viewed from above. As shown in Figure 7, in this Modification 2, the second flow path 132 has three first portions 132a and two second portions 132b.

Of the three first parts 132a, the first part 132a directly connected to the porous body 131 and the first part 132a furthest from the porous body 131 are positioned to overlap with the first channel 112 in a plan view, as shown in Figure 8. On the other hand, the first part 132a located in the middle of the three first parts 132a is positioned so as not to overlap with the first channel 112 in a plan view.

In the modified example 2, the three first portions 132a are connected by two second portions 132b to form a second flow channel 132. As a result, the second flow channel 132 in modified example 2 has a shape with multiple bends along its length.

This allows for the effective deactivation of charged particles in plasma that enter the first channel 112 when plasma is generated above the first surface 110a, by causing them to collide with the wall of the second channel 132.

Furthermore, in the modified example 2, the overall length of the channels can be made even longer compared to the case where the first channel 112 and the second channel 132 are located in a straight line from the first surface 110a of the ceramic substrate 110 to the lower surface of the base plate 120.

This allows charged particles in plasma generated above the first surface 110a to be effectively deactivated if they enter the first channel 112, even if they travel further along the longer channel.

Thus, in the modified example 2, the second flow path 132 has a structure in which it bends at multiple locations, thereby effectively suppressing the occurrence of abnormal discharges in the first flow path 112 and the second flow path 132.

In the example shown in Figure 7, the second channel 132 has three first portions 132a and two second portions 132b. However, this disclosure is not limited to this example, and the second channel 132 may have four or more first portions 132a and three or more second portions 132b.

<Example 3>
Figure 9 is an enlarged cross-sectional view showing the configuration of the embedded member 130 and its surroundings according to the third modified embodiment, and Figure 10 is a plan view showing an example of the configuration of the embedded member 130 according to the third modified embodiment as viewed from above.

As shown in Figure 9 and other figures, in this modified example 3, both of the two first portions 132a are positioned so as not to overlap with the first flow channel 112 in a plan view. For example, one first portion 132a is positioned close to the periphery of the porous body 131, and the other first portion 132a is positioned close to the periphery of the porous body 131 on the opposite side of the first first portion 132a.

As a result, in the modified example 3, when plasma is generated above the first surface 110a, if charged particles in the plasma enter the first channel 112, these charged particles can be effectively deactivated by colliding them with the walls of the voids in the porous body 131 and the walls of the second channel 132.

Furthermore, in the third modification, the overall length of the channels can be made even longer compared to the case where the first channel 112 and the second channel 132 are located in a straight line from the first surface 110a of the ceramic substrate 110 to the lower surface of the base plate 120.

This allows charged particles in plasma generated above the first surface 110a to be effectively deactivated if they enter the first channel 112, even if they travel further along the longer channel.

Thus, in the modified example 3, by arranging the first portion 132a of the second channel 132 so as not to overlap with the first channel 112 in a plan view, the occurrence of abnormal discharge in both the first channel 112 and the second channel 132 can be effectively suppressed.

<Modification 4>
Figure 11 is an enlarged cross-sectional view showing the configuration of the embedded member 130 and its surroundings according to the modified embodiment 4, and Figure 12 is a plan view showing an example of the configuration of the embedded member 130 according to the modified embodiment 4 as seen from above. As shown in Figure 12, in this modified embodiment 4, the second portion 132b is bent in plan view.

This allows for the effective deactivation of charged particles in plasma that enter the first channel 112 when plasma is generated above the first surface 110a, by causing them to collide with the wall of the second channel 132.

Furthermore, in Modification 4, the overall length of the channels can be made even longer compared to the case where the first channel 112 and the second channel 132 are located in a straight line from the first surface 110a of the ceramic substrate 110 to the lower surface of the base plate 120.

This allows charged particles in plasma generated above the first surface 110a to be effectively deactivated if they enter the first channel 112, even if they travel further along the longer channel.

Thus, in modified example 4, the second portion 132b has a structure that is further bent, which effectively suppresses the occurrence of abnormal discharge in the first flow path 112 and the second flow path 132.

<Example 5>
Figure 13 is an enlarged cross-sectional view showing the configuration of the embedded member 130 and its surroundings according to the modified embodiment 5, and Figure 14 is a plan view showing an example of the configuration of the embedded member 130 according to the modified embodiment 5 as seen from above.

As shown in Figure 13, in this modified example 5, the second portion 132b is bent in a side view. Furthermore, in modified example 5, the second portion 132b has a section through which the medium flows in a direction away from the first surface 110a (downward in Figure 13).

This allows for the effective deactivation of charged particles in plasma that enter the first channel 112 when plasma is generated above the first surface 110a, by causing them to collide with the wall of the second channel.

Furthermore, in Modification 5, the overall length of the channels can be made even longer compared to the case where the first channel 112 and the second channel 132 are located in a straight line from the first surface 110a of the ceramic substrate 110 to the lower surface of the base plate 120.

This allows charged particles in plasma generated above the first surface 110a to be effectively deactivated if they enter the first channel 112, even if they travel further along the longer channel.

Thus, in the modified example 5, by flowing the medium in a direction away from the first surface 110a, the occurrence of abnormal discharge in the first channel 112 and the second channel 132 can be effectively suppressed.

The sample holder 100 according to this embodiment comprises a ceramic substrate 110, a base plate 120, and an embedded member 130. The ceramic substrate 110 has a first surface 110a on which the object to be processed is placed, a second surface 110b located opposite the first surface 110a, and a first flow path 112 that penetrates between the first surface 110a and the second surface 110b. The base plate 120 is joined to the second surface 110b of the ceramic substrate 110 and has a through hole 122 at a position corresponding to at least the first flow path 112. The embedded member 130 has a porous body 131 at the end of the through hole 122 on the first flow path 112 side, and a second flow path 132 that communicates with the first flow path 112 via the porous body 131. Furthermore, the second flow path 132 has a first portion 132a perpendicular to the first surface 110a and a second portion 132b intersecting the first portion 132a. This suppresses the occurrence of abnormal discharges in both the first flow path 112 and the second flow path 132.

Furthermore, in the sample holder 100 according to this embodiment, the second portion 132b is parallel to the first surface 110a. This allows for the simple formation of the embedded member 130.

Furthermore, in the sample holder 100 according to this embodiment, the second channel 132 has a plurality of second portions 132b. This effectively suppresses the occurrence of abnormal discharge in the first channel 112 and the second channel 132.

Furthermore, in the sample holder 100 according to this embodiment, the first channel 112 and the first portion 132a of the second channel 132 are positioned so as not to overlap in a plan view. This effectively suppresses the occurrence of abnormal discharges in the first channel 112 and the second channel 132.

Furthermore, in the sample holder 100 according to this embodiment, the second portion 132b is bent in a plan view. This effectively suppresses the occurrence of abnormal discharge in the first channel 112 and the second channel 132.

Furthermore, in the sample holder 100 according to this embodiment, the second portion 132b has a portion through which the medium flows in a direction away from the first surface 110a. This effectively suppresses the occurrence of abnormal discharge in the first flow path 112 and the second flow path 132.

Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention. For example, in the above embodiments, an example was shown in which the porous body 131 is provided on the embedded member 130, but this disclosure is not limited to such an example, and the porous body 131 may be provided on the ceramic substrate 110.

Further effects and other embodiments can be readily derived by those skilled in the art. Therefore, broader embodiments of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

100 Sample holder 110 Ceramic substrate 110a First surface 110b Second surface 112 First channel 120 Base plate 122 Through hole 130 Embedded member 131 Porous body 132 Second channel 132a First part 132b Second part

Claims (6)

Ceramic substrate and
base plate and
It comprises an embedded member,
The ceramic substrate has a first surface on which the object to be processed is placed, a second surface located opposite the first surface, and a first channel that penetrates between the first surface and the second surface.
The base plate is bonded to the second surface of the ceramic substrate and has through holes at least at positions corresponding to the first flow path.
The embedded member has a porous body at the end on the first channel side within the through hole, and a second channel that communicates with the first channel through the porous body.
The second channel is,
A first portion extending in a first direction perpendicular to the first surface,
A sample holder having a second portion that communicates with the first portion and extends in a second direction that is bent with respect to the first direction . The sample holder according to claim 1, wherein the second portion is parallel to the first surface. The sample holder according to claim 1 or 2, wherein the second channel has a plurality of the second portions. The sample holder according to any one of claims 1 to 3, wherein the first channel and the first portion of the second channel are located in positions that do not overlap each other in a plan view. The sample holder according to any one of claims 1 to 4, wherein the second portion is bent in plan view. The sample holder according to any one of claims 1 to 5, wherein the second portion has a portion through which a medium flows in a direction away from the first surface.