JP5597155B2 - Vacuum adsorption apparatus and method for manufacturing the same - Google Patents

Description

  The present invention relates to an apparatus for vacuum-sucking an object such as a semiconductor wafer or a glass substrate in order to perform wet processing such as lapping.

  There has been proposed a vacuum suction device in which a placing portion made of a porous body and a support portion made of a dense body are integrally fired so that no gap is formed at the joint interface between them (see Patent Document 1). ). According to the vacuum suction device, the cleaning liquid can be prevented from leaking through the gap between the mounting portion and the support portion during cleaning, and contaminants such as grinding dust remaining in the porous body of the mounting portion can be sufficiently removed. .

Japanese Patent No. 4336532

  However, the adhesion between the mounting portion and the support portion may be slightly reduced due to the shrinkage of the porous body after the heat treatment such as firing.

  Then, an object of this invention is to provide the vacuum suction apparatus which can aim at the further improvement of the adhesiveness between a mounting part and a support part, and its manufacturing method.

  The present invention provides a support portion made of a dense ceramic sintered body provided with through-holes and a mounting portion made of a porous body formed by bonding ceramic powder serving as skeleton particles with glass. And a vacuum adsorbing device joined to the support portion by glass constituting the porous body in a state where the placement portion closes the through hole.

In the vacuum adsorption apparatus of the present invention, the average particle diameter is in the range of 2 to 30 [μm] , and the average particle diameter is the particle diameter D95 when the cumulative number from the small particle diameter side of the primary particles is 95% of the total particle number. 3 times in the range of or less, the primary particles said ceramic cumulative number from smaller particle size side is in a range particle diameter D3 is more than 0.25 times the average particle diameter of 3% of the total number of particles of The porous body is formed of a raw material composed of powder and glass powder, and the average pore diameter of the porous body constituting the mounting portion is in the range of 1 to 10 [μm] (excluding 10 [μm]) The placement portion is formed of a raw material having a ratio of the average particle diameter of the glass powder to the average particle diameter of the ceramic powder of 1/3 or less .

The porosity of the porous body is preferably in the range of 10 to 50 [%].

  The support part may be formed of a dense sintered body made of one kind of ceramic selected from alumina and silicon carbide.

  The manufacturing method of the vacuum suction device of the present invention includes a slurry adjustment step of adjusting a slurry by mixing the ceramic powder, the glass powder, and water or alcohol, and a ceramic dense sintered body serving as a support portion. A disappearing member filling step of filling a part of the through hole with a disappearing member so that the provided through hole is interrupted halfway, and a space formed by the through hole and the disappearing member is filled with the slurry. It includes a slurry filling step, a firing step of integrally firing the ceramic dense sintered body and the slurry filled in the space at a temperature equal to or higher than a softening point of glass.

Sectional drawing of the vacuum suction apparatus as one Embodiment of this invention.

(Configuration of vacuum suction device)
The vacuum suction apparatus as one embodiment of the present invention shown in FIG. 1 includes a mounting portion 1 made of a substantially flat porous body on which an object w such as a semiconductor wafer is mounted, and a substantially flat plate shape. And a support part 2 made of a ceramic dense body. A through hole 20 is formed in the support portion 2 so as to penetrate the center portion in the vertical direction. The upper space 21 of the through hole 20 is formed wider or larger in diameter than the lower space 22.

  The placement portion 1 is supported by the support portion 2 by joining the side wall of the upper space 21 of the through hole 20 to the periphery of the placement portion 1 over the entire circumference. The joint interface 12 between the mounting portion 1 and the support portion 2 is integrally fired without a gap. “It is fired integrally with no gap” means that the porous body structure of the mounting portion 1 is continuous up to the interface contacting the support portion 2 and the bonding interface between the mounting portion 1 and the support portion 2. This means that there is no gap in 12 and the placing part 1 and the supporting part 2 are integrally fired.

  The upper end surface of the mounting portion 1 is formed by polishing together with the upper end surface of the support portion 2 or its surrounding portion. The upper end surface of the placement unit 1 and the upper end surface of the support unit 2 are included on the same plane. As the through hole 20 is sucked from the lower space 22 side by a vacuum pump (not shown), the object w is vacuum-sucked to the mounting portion 1.

  The porous body constituting the mounting part 1 is manufactured from raw materials including ceramic powder and glass powder. Alumina or silicon carbide powder is employed as the ceramic powder. The purity is included in the range of 95.5 to 99.5 [%], the average particle diameter is included in the range of 2 to 30 [μm], D95 is included in the range of three times or less of the average particle diameter, and A ceramic powder in which D3 is included in a range of 0.25 times or more of the average particle diameter is used. “D95” means the particle size when the cumulative number of primary particles from the small particle size side is 95% of the total number of particles. “D3” means the particle size when the cumulative number of primary particles from the small particle size side is 3 [%] of the total number of particles.

  Glass having a thermal expansion coefficient smaller than that of ceramics is used. Thereby, the clearance gap of the joining interface of the mounting part 1 and the support part 2 can be eliminated. Moreover, the state where the compressive stress was added to the glass which has a role as a binder in the porous body which comprises the mounting part 1 is implement | achieved.

  Moreover, in the constituent raw material of the mounting part 1, the ratio of the average particle diameter of the glass powder to the average particle diameter of the ceramic powder is 1/3 or less. As a result, the glass powder hinders the filling of the ceramic powder, and firing shrinkage is prevented when sintering is performed at a temperature equal to or higher than the glass softening point.

  The amount of the glass powder added to the ceramic powder is adjusted to a mass ratio in the range of 5 to 30% in consideration of the target porosity, the particle size of the ceramic powder, the firing temperature, the glass viscosity, and the like. Thereby, the firing shrinkage of the porous body is prevented, and the bonding strength of the ceramic powder is ensured sufficiently high.

(Manufacturing method of vacuum suction device)
The manufacturing method of the vacuum suction device of the present invention includes a “slurry adjusting step”, a “disappearing member filling step”, a “slurry filling step”, and a “firing step”. Since the ceramic molded body constituting the support part 2 by firing has the same configuration as the support part, the same reference numerals as those assigned to the support part 2 are given.

  In the slurry adjustment step, the slurry is adjusted by mixing ceramic powder and glass powder, which are the raw material powder of the porous body, and water or alcohol. As the mixing method, a known method using a ball mill or a mixer can be applied. The addition amount of water or alcohol can be arbitrarily adjusted so as to obtain a slurry having a desired fluidity in consideration of the particle size of the ceramic powder and the addition amount of the glass powder.

  Further, in the vanishing member filling step, the vanishing member is filled into a part of the through hole so that the through hole 20 provided in the ceramic dense sintered body of the support portion 2 is blocked on the way. For example, in the through hole 20, the lower space 22 and the lower space 22 of the upper space 21 are filled with a burning member such as wax or resin. The ceramic dense sintered body is made of alumina or silicon carbide.

  Next, in the slurry filling step, the slurry is filled into the space formed by the through hole 20 and the disappearing member, for example, the upper space of the upper space 21. At this time, if necessary, vacuum defoaming may be performed to remove residual bubbles in the slurry, or vibration may be applied to increase the filling rate.

  In the firing step, after the ceramic molded body in which the slurry is filled in the space formed by the disappearing member is sufficiently dried, the ceramic dense sintered body and the slurry-derived raw material are heated at a temperature equal to or higher than the softening point of the glass. Fired integrally. At this time, if the firing temperature is too high, deformation or shrinkage occurs in the mounting portion 1. Therefore, it is desirable to perform firing at as low a temperature as possible (for example, 1000 [° C.]) even if it is above the softening point of glass. In the firing step, the disappearing member that has blocked the through hole 20 disappears.

  Then, the suction surface of the vacuum suction device was obtained by polishing with a diamond grindstone so that the upper end surface of the mounting portion 1 and the upper end surface of the support portion 2 were flush with each other.

(Example)
Example 1
As ceramic powder, the average particle diameter D is 10 [μm], D95 is 30.0 [μm], 3.0 times the average particle diameter D, and D3 is 3.0 [μm] An alumina powder having an average particle diameter D of 0.3 times was used. The purity of the alumina powder is, for example, 96.5 [%]. The glass powder has an average particle size of 3.0 [μm], 0.3 times the average particle size of the ceramic powder, a thermal expansion coefficient of 4.0 × 10 ⁻⁶ / ° C., and a softening point of 800 ° C. Silicate glass was used. Ceramic powder, glass powder and distilled water were mixed at a mass ratio of 100: 20: 20 and kneaded by a mixer to prepare a slurry.

  As a ceramic dense sintered body, a through-hole 20 having an outer diameter of 250 [mm] and a thickness of 50 [mm] and penetrating through the center of the disk in the vertical direction or thickness direction is formed. A dense sintered body of alumina was used. Slurry was filled in a cylindrical space having an inner diameter of 200 [mm] and a depth of 40 [mm] formed by the molded body and the disappearing member. After vacuum defoaming in the slurry was performed, vibration was applied to settle and fill the slurry. As shown in FIG. 1, the ceramic dense sintered body and the slurry filled in the space are dried at 100 [° C.] for 2 hours and then fired at 1000 [° C.] for 3 hours. A vacuum suction device was manufactured.

(Example 2)
The average particle diameter D of the ceramic powder contained in the raw material of the mounting portion 1 is 2.0 [μm], D95 is 5.0 [μm], 2.5 times the average particle diameter D, and D3 Is 1.2 [μm] and is 0.6 times the average particle diameter D, and the average particle diameter of the glass powder is 0.6 [μm]. A vacuum suction device was manufactured.

(Example 3)
The average particle diameter D of the ceramic powder contained in the raw material of the mounting portion 1 is 30 [μm], D95 is 50 [μm], 1.67 times the average particle diameter D, and D3 is 19 [μm]. And the average particle size of the glass powder is 4.0 [μm] and 0.13 times the average particle size of the ceramic powder, A vacuum adsorption device was manufactured under the same conditions as in Example 1.

Example 4
A vacuum adsorption apparatus under the same conditions as in Example 1 except that D3 of the ceramic powder contained in the raw material of the mounting portion 1 is 6.5 [μm] and 0.65 times the average particle diameter D. Was manufactured.

(Example 5)
D95 of the ceramic powder contained in the raw material of the mounting portion 1 is 15.0 [μm], 1.5 times the average particle diameter D, D3 is 2.5 [μm], and the average particle diameter D A vacuum suction device was manufactured under the same conditions as in Example 1 except that the ratio was 0.25 times.

  In any of the examples, no cracks or gaps were observed at the bonding interface 12 between the porous mounting portion 1 and the support portion 2. Table 1 summarizes a part of the manufacturing conditions of each example and the confirmation results such as the presence or absence of cracks at the bonding interface 12.

  As is apparent from Table 1, according to Examples 1 to 5, the porosity of the porous body is within the range of 10 to 50 [%].

(Comparative example)
(Comparative Example 1)
Except for the point that the average particle diameter D of the ceramic powder is 1.0 [μm] and is smaller than the lower limit of 2 to 30 [μm], (D95 / D) is 3 or less, and (D3 / D) is The vacuum suction device was manufactured under the same conditions as in Example 1, including that the values were 0.25 or more and {D / (average particle diameter of glass powder)} was 1/3 or less. It was done.

(Comparative Example 2)
The average particle diameter of the ceramic powder is 40 [μm], and (D95 / D) is 3 or less, and (D3 / D) is 0.25, except that it is larger than the upper limit of 2 to 30 [μm]. The vacuum adsorption apparatus was manufactured under the same conditions as in Example 1 including the above and matching that {D / (average particle diameter of glass powder)} was 1/3 or less.

(Comparative Example 3)
Except for the point that D95 of the ceramic powder is 40 [μm] and exceeds 3 times the average particle diameter D, the average particle diameter D is included in the range of 2 to 30 [μm], (D3 / D) Is equal to or greater than 0.25, and {D / (average particle diameter of glass powder)} is equal to or less than 1/3, and the vacuum adsorption apparatus is under the same conditions as in Example 1. manufactured.

(Comparative Example 4)
Except for the point that D3 of the ceramic powder is 2.0 [μm] and less than 0.25 times the average particle diameter D, the average particle diameter D is included in the range of 2 to 30 [μm] (D95 / D) is 3 or less, and {D / (average particle diameter of the glass powder)} is the same as that of Example 1, including that they are equal to 1/3 or less. Was manufactured.

(Comparative Example 5)
The average particle diameter of the glass powder is 4.0 [μm], and the average particle diameter D is in the range of 2 to 30 [μm] except that the average particle diameter exceeds 1/3 times the average particle diameter of the ceramic powder. And a vacuum adsorption device was produced under the same conditions as in Example 1 including that they coincided with each other in that (D95 / D) was 3 or less.

  In Comparative Examples 1 to 3, the average pore diameter of the porous body is out of the range of 1 to 10 [μm]. In Comparative Examples 1, 3, and 4, the porosity of the porous body is out of the range of 10 to 50 [%]. In all of Comparative Examples 1 to 5, cracks or gaps were observed at the bonding interface 12 between the placement portion 1 and the support portion 2. In particular, in Comparative Example 5, a very large gap was observed. Table 2 summarizes the results of confirmation of part of the manufacturing conditions of each comparative example and the presence or absence of cracks at the bonding interface 12.

  As apparent from Table 2, according to Comparative Example 1, the porosity of the porous body is 55%, which is out of the above range (10 to 50 [%]). This is because, in this production method, if the average particle size of the ceramic powder is too small, the filling rate of the skeleton particles is deteriorated, so that the porosity tends to increase. Moreover, according to the comparative example 2, the average pore diameter of the porous body is 15.0 [μm], which is out of the range (1 to 10 [μm]). This is because if the average particle diameter of the ceramic powder is too large, the space between the filling of the skeleton particles becomes large. According to Comparative Example 3, the porosity of the porous body is 52%, which is out of the above range. This is because when D95 is too large, the filling rate of the skeletal particles deteriorates, and the porosity tends to increase. As described above, when the porosity or average pore diameter of the porous body is too large, the contact surface with the bonding interface 12 is reduced, and thereby the bonding strength is weakened, so that a gap is generated.

  According to Comparative Example 4, the porosity of the porous body is 8%, which is out of the above range. This is because when D3 is too small, the filling rate of the skeleton particles is improved and the porosity tends to be low. According to the comparative example 5, the glass powder of a porous body is 1/3 times or more of D, and has remove | deviated from the said range. Thus, if the filling rate of the skeleton particles is too high, or the average particle diameter of the glass powder is too large, remarkable firing shrinkage occurs and integration cannot be performed.

(Effect of the invention)
According to the present invention, a vacuum suction device in which the adhesion between the placement unit 1 and the support unit 2 is further improved can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Mounting part, 12 ... Joining interface, 2 ... Supporting part, 21 ... Upper space, 22 ... Lower space, w ... Object.

Claims (4)

A support portion made of a dense ceramic sintered body provided with through-holes, and a placement portion made of a porous body formed by bonding ceramic powder serving as skeletal particles with glass, A vacuum suction device joined to the support portion by glass constituting the porous body in a state where the placement portion closes the through hole,
The average particle size is in the range of 2 to 30 [μm] , and the cumulative number from the small particle size side of the primary particles is in the range where the particle size D95 at 95% of the total number of particles is not more than 3 times the average particle size . And the ceramic powder in which the cumulative number from the small particle size side of the primary particles is 3% of the total particle number and the particle diameter D3 is in the range of 0.25 times or more of the average particle diameter, and the glass powder. The porous body is formed by raw materials,
The average pore diameter of the porous body constituting the mounting portion is in the range of 1 to 10 [μm] (except 10 [μm]),
The vacuum suction apparatus, wherein the placement portion is formed of a raw material having a ratio of an average particle diameter of the glass powder to an average particle diameter of the ceramic powder of 1/3 or less . The vacuum suction apparatus according to claim 1,
The vacuum adsorbing device, wherein the porosity of the porous body is in a range of 10 to 50 [%]. The vacuum suction apparatus according to claim 1 or 2 ,
The vacuum adsorbing device, wherein the support portion is formed of a dense sintered body made of one kind of ceramic selected from alumina and silicon carbide. It is a manufacturing method of the vacuum adsorption device according to any one of claims 1 to 3 ,
A slurry adjustment step of adjusting a slurry by mixing the ceramic powder, the glass powder, and water or alcohol;
A vanishing member filling step of filling the vanishing member into a part of the through hole so that the through hole provided in the ceramic dense sintered body serving as the support portion is interrupted in the middle;
A slurry filling step of filling the slurry into the space formed by the through hole and the disappearing member;
And a firing step of integrally firing the ceramic dense sintered body serving as the support portion and the slurry filled in the space at a temperature equal to or higher than a softening point of glass.

Images