JP7055729B2 - Sample holder - Google Patents

Description

The present disclosure relates to a sample holder for holding a sample such as a semiconductor wafer, which is used in a manufacturing process of a semiconductor integrated circuit, a manufacturing process of a liquid crystal display device, or the like.

As a sample holder, for example, a semiconductor manufacturing / inspection apparatus disclosed in Patent Document 1 is known. In the apparatus disclosed in Patent Document 1, a ceramic substrate provided with a heat generation resistor is fitted in the upper part of a cylindrical casing, and a bottom plate and a middle bottom plate are further provided. The bottom plate and the middle bottom plate are provided with a plurality of openings in order to improve the cooling rate. Further, in order to improve the flatness, a large number of dents are formed on the surfaces of the bottom plate and the in-bottom plate.

Japanese Unexamined Patent Publication No. 2002-141399

For example, in the inspection process, in order to accelerate the cycle of the temperature cycle, it is necessary to increase the rate of temperature increase and the rate of temperature decrease of the surface of the ceramic substrate. In the manufacturing process, it is necessary to increase the temperature lowering rate of the ceramic substrate surface in order to shorten the time required for the temperature to drop to the temperature at which the next work is set. In the semiconductor manufacturing / inspection apparatus disclosed in Patent Document 1, the bottom plate spaced from the ceramic substrate is heated by heat radiation from the ceramic substrate. Especially in the central part of the bottom plate, heat radiation is concentrated and becomes high temperature. In addition, it is difficult to increase the rate of temperature decrease because heat does not easily escape.

The sample holder according to one aspect of the present disclosure includes a plate-shaped ceramic body having a sample holding surface on the upper surface thereof.
With the heat generation resistor provided inside or on the lower surface of the ceramic body,
It is provided below the ceramic body so as to be separated from the ceramic body and the main surface faces the ceramic body, and has a central portion and an outer peripheral portion surrounding the central portion, and the central portion and the outer peripheral portion. A metal plate with holes in each
It is provided with the ceramic body and a fixing member for fixing the outer peripheral portion.
The central portion has a higher aperture ratio than the outer peripheral portion.
The metal plate is characterized in that the entire inside of the central portion of the main surface is recessed, and the central portion is thinner than the outer peripheral portion .

According to the sample holder of one aspect of the present disclosure, in the metal plate having a hole, the opening ratio of the central portion is higher than that of the outer peripheral portion, so that the area for absorbing thermal radiation is small and the temperature rise in the central portion is reduced. Will be done. Further, the high aperture ratio promotes the exhaust heat from the hole portion, and the temperature lowering rate can be increased.

It is sectional drawing which shows one Embodiment of the sample holder of this disclosure. It is a top view of a metal plate. It is sectional drawing which shows the other embodiment of the sample holder of this disclosure.

Hereinafter, the sample holder 100 according to the embodiment of the present disclosure will be described. FIG. 1 is a cross-sectional view showing an embodiment of the sample holder of the present disclosure. The sample holder 100 includes a sample holding plate 1, a heat generating resistor 2 provided on the sample holding plate 1, a metal plate 3 located below the sample holding plate 1 and supporting the sample holding plate 1, and a sample. A plurality of fixing members 4 for fixing the holding plate 1 and the metal plate 3 are provided.

The sample holding plate 1 is a plate-shaped ceramic body whose upper surface is the sample holding surface 1a. The outer shape of the sample holding plate 1 is not particularly limited, but is, for example, a disk shape. The sample holding plate 1 is made of a ceramic material, and as the ceramic material, a ceramic material containing silicon carbide, boron carbide, boron nitride, silicon nitride or aluminum nitride as a main component can be used. The dimensions of the sample holding plate 1 are, for example, in the case of a disk shape, the diameter of the sample holding surface is 200 to 500 mm, and the thickness is 1 to 7 mm.

The heat generation resistor 2 is a heat generation member for heating a sample (held object) such as a silicon wafer held on the sample holding surface 1a. The heat generation resistor 2 is provided inside the sample holding plate 1 or on the lower surface 1b on the opposite side of the sample holding surface 1a. In the sample holder 100 of the present embodiment, the heat generation resistor 2 is provided on the lower surface 1b of the sample holding plate 1. The heat generation resistor 2 is formed in a band shape, for example. The band-shaped heat-generating resistor 2 is arranged in a spiral shape, a zigzag shape, a meander shape, or the like over the entire lower surface 1b of the sample holding plate 1. The heat generation resistor 2 is made of a metal material such as gold, silver, palladium or platinum, and generates Joule heat when energized.

The metal plate 3 is a member for supporting the sample holding plate 1. The metal plate 3 is located below the sample holding plate 1 and supports the sample holding plate 1 via the fixing member 4. The outer shape of the metal plate 3 is not particularly limited, but is, for example, the same shape as the outer shape of the sample holding plate 1. The metal plate 3 of the present embodiment has a disk shape, and is provided so that the main surface 3a on the upper side of the sample holding plate 1 faces the sample holding plate 1 away from the sample holding plate 1. .. The lower surface 1b of the sample holding plate 1 and the main surface 3a of the metal plate 3 face each other with a certain interval.

The metal plate 3 is made of a metal material, and as the metal material, for example, iron, stainless steel, or the like can be used. The dimensions of the metal plate 3 are, for example, in the case of a disk shape, the diameter of the main surface is 200 to 500 mm, which is the same as that of the sample holding plate 1, and the thickness is 1 to 10 mm.

A plurality of fixing members 4 are provided between the metal plate 3 and the sample holding plate 1, whereby the metal plate 3 and the sample holding plate 1 are fixed. The fixing member 4 fixes the sample holding plate 1 by sandwiching and tightening the outer edge portion of the sample holding plate 1, for example. The fixing member 4 is attached to, for example, a metal plate 3 by an elastic force of a spring. A plurality of fixing members 4 are provided along the outer edge of the sample holding plate 1. The fixing members 4 are arranged at the outer edge of the sample holding plate 1 at equal intervals in the circumferential direction. This reduces the occurrence of biased deformation of the sample holding plate 1. The fixing member 4 is made of a metal material such as stainless steel.

Hereinafter, the configuration of the metal plate 3 which is a feature of the present disclosure will be described in detail. FIG. 2 is a plan view of the metal plate 3. The metal plate 3 has a plurality of holes 3H penetrating from the main surface 3a on the upper side to the main surface 3b on the lower side opposite to the main surface 3a. Further, the metal plate 3 has a central portion 30 and an outer peripheral portion 31 in a plan view. In the central portion 30, when the radius of the upper main surface 3a is r, half of the radius is r / 2, and the central portion is the entire inner portion of the circle whose center is the same as the center of the main surface 3a. It's called 30. The outer peripheral portion 31 is a portion connected to the central portion 30 and surrounds the central portion 30. That is, the metal plate 3 is the outer peripheral portion 31 except for the central portion 30.

The hole portion 3H penetrating the metal plate 3 in the thickness direction is provided in both the central portion 30 and the outer peripheral portion 31. In the following, the hole located in the central portion 30 will be referred to as the hole portion 30H, and the hole portion located in the outer peripheral portion 31 will be referred to as the hole portion 31H. When the whole hole portion is generically referred to, the hole portion 3H is used. In the metal plate 3 of the present disclosure, the central portion 30 has a higher aperture ratio than the outer peripheral portion 31. A plurality of openings are located in the metal plate 3 by the hole portion 30H of the central portion 30 and the hole portion 31H of the outer peripheral portion 31. The outer shape of the opening of the hole 3H is not limited to a circle, but may be an ellipse, a rectangle, a polygon, an irregular shape, or the like. When the outer shape of the opening is irregular, the diameter equivalent to a circle may be calculated by a known method and converted into the area equivalent to a circle.

The aperture ratio of the central portion 30 is the ratio of the total opening area to the area of the central portion 30. The area Sc of the central portion 30 is an area including an opening, and when the radius of the main surface 3a is r, the radius of the central portion 30 is r / 2, so the area Sc = πr ^2/4 . The total opening area sc of the central portion 30 is the sum of the opening areas of each hole portion 30H, and if the opening area of each hole portion 30H is sc1, sc2, sc3, ..., The total opening area sc = sc1 + sc2 + sc3 + ... .. Therefore, the aperture ratio Ac of the central portion 30 is calculated by Ac = sc / Sc.

The aperture ratio of the outer peripheral portion 31 is the ratio of the total opening area to the area of the outer peripheral portion 31. The area Sp of the outer peripheral portion 31 is an area including an opening, and when the radius of the main surface 3a is r, the area S of the main surface 3a is S = πr ² , and the area Sc of the central portion 30 is Sc = πr ^2/4 . Therefore, the area of the outer peripheral portion 31 is Sp = S-Sc = πr ² -πr ^2/4 = 3πr ^2/4 . The total opening area sp of the outer peripheral portion 31 is the total opening area of each hole portion 31H, and if the opening area of each hole portion 31H is sp1, sp2, sp3, ..., The total opening area sp = sp1 + sp2 + sp3 + ... .. Therefore, the aperture ratio Ap of the outer peripheral portion 31 is calculated by Ap = sp / Sp.

In the metal plate 3 of the present disclosure, the relationship between the aperture ratio of the central portion 30 and the outer peripheral portion 31 is Ac> Ap, and the central portion 30 has a higher aperture ratio than the outer peripheral portion 31. The aperture ratio Ac and the aperture ratio Ap may be calculated by directly measuring the metal plate 3, or the main surface 3a of the metal plate 3 is photographed and known image analysis software (A image-kun (registered trademark)). It may be calculated using Asahi Kasei Engineering Co., Ltd.).

When the opening ratio of the central portion 30 is high, the portion that absorbs the thermal radiation from the heat generation resistor 2 becomes relatively small, and the temperature rise of the central portion 30 of the metal plate 3 due to the thermal radiation is reduced. Further, when the temperature is lowered (cooled), the high aperture ratio promotes the exhaust heat from the hole 3H, and the temperature lowering rate can be increased. Further, since the opening ratio of the outer peripheral portion fixed to the sample holding plate by the fixing member is low, the durability of the metal plate in the fixing portion can be enhanced.

If the relationship of the aperture ratio is Ac> Ap, the above effect is obtained. Therefore, the distribution of the opening diameter of each hole 3H in the entire metal plate 3 is not particularly limited, but more preferably, of the plurality of holes 3H. The hole portion 3H having the largest diameter is located in the central portion 30. The opening diameters of the holes 3H provided in the metal plate 3 may be the same or different as long as Ac> Ap. When the opening diameters are different, the hole portion 3H having the maximum opening diameter is included in the hole portion 30H located in the central portion 30. When there are a plurality of hole portions 3H having the maximum opening diameter, it is preferable that all of them are located in the central portion 30, but some of them are located in the central portion 30 and the other portion is located in the outer peripheral portion 31. May be good. When the hole portion 3H having the maximum diameter is dispersed in the central portion 30 and the outer peripheral portion 31, the maximum diameter hole portion 30H located in the central portion 30 and the maximum diameter hole portion 31H located in the outer peripheral portion 31 are The number of holes 30H having the same number or the maximum diameter located in the central portion 30 is larger.

By making the distribution of the opening diameter of the hole portion 3H as described above, the exhaust heat from the hole portion 30H in the central portion 30 is further promoted, and the temperature lowering rate can be further increased.

If the relationship of the aperture ratio is Ac> Ap, the above effect is obtained. Therefore, the position where each hole portion 3H is provided in the entire metal plate 3 is not particularly limited, but more preferably, the hole portion 3H is the metal plate 3 and the hole portion 3H. They are provided at equal intervals on the circumference of the same center. If the arrangement position of the hole portion 3H provided in the metal plate 3 is Ac> Ap, it may be arranged unevenly without regularity, but it may be arranged according to a certain rule. When the hole portions 3H are arranged according to the rules, for example, the hole portions 3H may be arranged at grid points, may be arranged radially along the radial direction, and may be arranged at equal intervals on concentric circles. May be. The hole portion 30H located in the central portion 30 and the hole portion 31H located in the outer peripheral portion 31 are arranged on the circumference concentric with the center of the metal plate 3 at equal intervals in the circumferential direction. The holes 3H arranged on the same circumference preferably have the same opening diameter, but the opening diameters may be different from each other.

By arranging the holes 3H at equal intervals on the circumference as described above, the heat equalization in the circumferential direction can be improved.

FIG. 3 is a cross-sectional view showing another embodiment of the sample holder of the present disclosure. Since the sample holder 100 of the present embodiment is the same as the sample holder 100 of the embodiment shown in FIGS. 1 and 2 except that the structure of the metal plate 3 is different, the same reference numerals are given to the same parts. The detailed explanation will be omitted. The thickness of the metal plate 3 of the present embodiment is different between the central portion 30 and the outer peripheral portion 31, and the central portion 30 is thinner than the outer peripheral portion 31. Specifically, the thickness of the central portion 30 is 20 to 60% with respect to the thickness of the outer peripheral portion 31.

By reducing the thickness of the central portion 30, the portion that absorbs the thermal radiation from the heat generation resistor 2 becomes smaller, and the temperature rise can be further reduced. On the other hand, since the outer peripheral portion 31 fixed to the sample holding plate 1 by the fixing member 4 is thick, it has sufficient rigidity and can secure the mechanical strength of the sample holder 100.

Since the central portion 30 is thinner than the outer peripheral portion 31, the boundary portion between the central portion 30 and the outer peripheral portion 31 is, for example, in a stepped shape as shown in FIG. 3 in the present embodiment. The boundary portion is not limited to a stepped shape, but may be an inclined shape or a curved surface shape.

Next, a method for manufacturing the sample holder of the present disclosure will be described. Hereinafter, an example of a method for manufacturing the sample holder 100 according to the embodiment shown in FIG. 1 will be described. Although the case where alumina ceramics are used for the sample holding plate 1 will be described as an example, it can be manufactured by the same method even in the case of other ceramic materials such as aluminum nitride ceramics.

First, a predetermined amount of alumina powder having a particle size of 0.1 to 2 μm, which is the main raw material, and a small amount of sintering aid are weighed, and in a ball mill, ion-exchanged water or an organic solvent and high-purity alumina balls are used together with 24-72. Wet grind mixing for hours.

A predetermined amount of an organic binder such as polyvinyl alcohol, polyvinyl butyral or acrylic resin and a plasticizer and an antifoaming agent as auxiliary organic materials are added to the raw material slurry pulverized and mixed in this manner, and the mixture is further mixed for 24 to 48 hours. The mixed organic-inorganic mixed slurry is formed into a ceramic green sheet having a thickness of 20 μm to 20 mm by a doctor blade method, a calendar roll method, a press molding method, an extrusion molding method, or the like.

Then, a paste-like resistor material such as platinum or tungsten for forming the heat generating resistor 2 is printed and molded on the ceramic green sheet forming the sample holding plate 1 by a known screen printing method or the like.

Here, a ceramic green sheet on which the paste-like resistor material is not printed and a resistor-forming green on which the paste-like resistor material is printed so that the heat generating resistor 2 is formed at a predetermined position on the sample holding plate 1. Stack with the sheet. Lamination is performed at a predetermined temperature while applying a pressure equal to or higher than the yield stress value of the ceramic green sheet. As the pressure application method, a known technique such as a uniaxial pressing method or an isotropic pressurization method may be applied. By firing the obtained laminate in a predetermined temperature and in a predetermined atmosphere, a sample holding plate 1 in which the heat generation resistor 2 is formed or embedded in the surface is produced. The sample holding plate 1 is machined into a predetermined shape and thickness using a machining center, a rotary processing machine or a cylindrical grinding machine.

On the other hand, a disk-shaped stainless steel plate to be a metal plate 3 is cut out from the stainless steel block by slicing, and through holes are provided at predetermined positions using a drilling device such as a machining center or a drilling machine to form a plurality of holes 3H. A metal plate having a metal plate is manufactured. The sample holding plate 1 and the metal plate 3 are fixed by using the fixing member 4 prepared in advance, and the sample holding tool 100 of the present disclosure is obtained.

1 Sample holding plate 1a Sample holding surface 1b Bottom surface 2 Heat-generating resistor 3 Metal plate 3H Hole 4 Fixing member 30 Central 30H (Central) hole 31 Outer peripheral 31H (Outer peripheral) hole 100 Sample holder

Claims (3)

A plate-shaped ceramic body whose upper surface is the sample holding surface,
With the heat generation resistor provided inside or on the lower surface of the ceramic body,
It is provided below the ceramic body so as to be separated from the ceramic body and the main surface faces the ceramic body, and has a central portion and an outer peripheral portion surrounding the central portion, and the central portion and the outer peripheral portion. A metal plate with holes in each
It is provided with the ceramic body and a fixing member for fixing the outer peripheral portion.
The central portion has a higher aperture ratio than the outer peripheral portion.
The metal plate is a sample holder characterized in that the entire inside of the central portion of the main surface is recessed, and the central portion is thinner than the outer peripheral portion . The sample holder according to claim 1 , wherein the hole having the largest diameter among the plurality of holes is located at the center of the hole. The sample holder according to claim 1 or 2, wherein the holes are provided at equal intervals on a circumference having the same center as the metal plate.

Images