JP2003234398A - Absorption table for curved surface wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a absorption table for a curved surface wafer for absorbing the curved surface wafer using a simple mechanism. <P>SOLUTION: The absorption table for the curved surface wafer can absorb the curved surface wafer 11 in surely contact with it by an elastic contact body 2 which is formed into a nearly D-shaped ring and tilts downward toward the inner peripheral side from an outer peripheral side along the radial direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suction for a curved wafer, which attracts and fixes a wafer having a curved surface (hereinafter, referred to as a curved wafer to distinguish such a wafer from a normal wafer) in a semiconductor manufacturing process. Regarding the stand.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a rod-shaped silicon single crystal is sliced to cut a thin disk-shaped wafer. The surface of this wafer is polished and mirror-finished, and then subjected to thin film formation, lithography, etching, impurity introduction, cleaning, heat treatment, etc.
A completed wafer is obtained by allocating a plurality of chips such as CMOS in a grid pattern.

In the semiconductor manufacturing process described above, a wafer suction table is used to fix the wafer and perform various operations. Such a wafer suction table will be briefly described with reference to the drawings. FIG. 5 is an explanatory view for explaining a conventional wafer suction table, FIG. 5 (a) is a sectional view taken along the line AA of the wafer suction table, FIG. 5 (b) is the same plan view, and FIG. 4] is an explanatory view of problems when a curved surface wafer is placed. Note that the wafer 40 is illustrated in FIG. 5A for easy understanding of the drawing, but in FIG. 5B, only the suction table main body 10 is shown as a plan view and the wafer 40 is not illustrated.

As shown in FIGS. 5 (a) and 5 (b), the wafer suction table comprises a suction table body 10, a suction recess 20,
An exhaust port 30 is provided. The wafer 40 is placed on the wafer suction table. Adsorption of the wafer 40 by the wafer adsorption table having such a configuration is as follows.

First, as shown in FIG. 5A, a wafer 40 is placed on the suction table body 10. The contact surface of the suction table main body 10 with which the wafer 40 comes into contact is subjected to Teflon treatment or the like after being finished in a flat surface so that almost no gap can be formed at the time of contact. And the exhaust port 30
Evacuation is started by a vacuum pump (not shown) connected to the. As the evacuation progresses, the space closed by the wafer 40 and the suction recess 20 approaches a vacuum, and the wafer 40 is sucked and firmly fixed onto the suction table body 10. The suction force on the wafer 10 is applied to the suction concave portion 20 (dotted portion) as shown in FIG. The suction concave portion 20 is formed in a substantially D shape so as to match the shape of the wafer 40 (a shape in which a notch called an orientation flat portion is provided on a disk). The conventional wafer suction table has such a structure.

[0006]

However, the wafer 40 suffers from stress received during slicing and surface polishing.
Due to various factors such as internal stress, the curved wafer 40 'may be curved as shown in FIG. 5C.

When such a curved wafer 40 'is placed on the wafer suction table, the contact surface of the suction table body 10 and the curved wafer 40' are not in close contact with each other as shown in FIG. A closed space cannot be formed between the concave portion 20 for a curved surface and the curved wafer 40 ′, and an air entry portion occurs. Even if an attempt is made to adsorb such a curved wafer 40 ', air enters from an air entry point and the vacuum state is never reached, so that the vacuum adsorption of the curved wafer 40' was impossible.

In reality, the curved wafer 40 'is not an extremely curved curved wafer 40' as shown in FIG. 5 (c), but it is a curved wafer which cannot be visually observed.
However, it cannot be vacuum-adsorbed. As described above, when the vacuum suction is not possible, the curved wafer 40 'becomes a defective product because the semiconductor manufacturing process cannot be proceeded to, so that there is a problem that the manufacturing yield cannot be improved.

Further, in recent years, a wafer having a diameter of the wafer 40 of 8 inches (about 20 cm) is mainly used, but in order to further improve the manufacturing department, for example, a wafer of 12 inches (about 30 cm) larger than the conventional wafer. There is a request to be able to handle. However, as the size of the wafer 40 becomes larger, the probability of occurrence of the curved wafer 40 ′ may rather increase, and it may not be possible to achieve the prospect of improving the manufacturing yield. Due to such circumstances, curved wafer 4
Curved wafer 4 that can surely attract even 0 '
0'suction table (hereinafter referred to as curved wafer suction table)
Was sought after.

The present invention is to solve the above problems, and an object thereof is to provide a curved wafer suction table for sucking a curved wafer with a simple mechanism.

[0011]

In order to solve the problems of the present invention, according to the curved surface wafer suction table of the first aspect of the present invention, there is provided a suction table body and a substantially D-shaped ring having a substantially concave cross section. An elastic contact member arranged on the suction table body so as to incline downward from the outside in the radial direction of the ring, a hole provided on the bottom surface of the groove of the elastic contact member, and a hole And an exhaust port provided in the suction table body so as to communicate with the above.

According to the curved wafer suction table of the present invention as defined in claim 2, in the curved wafer suction table according to claim 1, the suction table main body is located in the ring of the elastic contact member. It is characterized by comprising an air supply port formed.

According to the curved wafer suction table of the third aspect of the present invention, in the curved wafer suction table of the first or second aspect, the elastic contact member is provided from the outside in the radial direction of the ring. Since the groove is formed in the suction table body so as to be inclined downward toward the inner side, the groove is formed in the suction table body so as to have a substantially D-shaped annular shape, and the groove bottom surface on the inner peripheral side is low, and It is characterized in that it is provided with a recess for elastic contact member placement in which the groove bottom surface is formed in multiple stages so that the groove bottom surface on the outer peripheral side becomes high.

According to the curved wafer suction table of the fourth aspect of the present invention, in the curved wafer suction table according to any one of the first to third aspects, the elastic contact member is preferably Is made of chloroprene rubber having a hardness of 45 as a material.

Further, according to the curved wafer suction table of the invention of claim 5, in the curved wafer suction table according to any one of claims 1 to 4, the groove portion of the elastic contact member is provided. A plurality of holes provided on the bottom surface, a collective exhaust recess provided on the suction table body on the rear surface of the surface where the elastic contact member is disposed, and a sealing body that seals the collective exhaust recess connected to the plurality of holes. And are provided.

According to the curved wafer suction table of the invention as defined in claim 6, in the curved wafer suction table according to claim 5, the collective exhaust concave portion is annular and the seal body is the collective body. An O-ring that is in close contact with and closes the opening of the exhaust recess.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment of a suction pad for a curved wafer of the present invention, FIG. 2 is an explanatory view of an elastic contact member, FIG. 3 is an explanatory diagram of an elastic contact member and a recess for arranging the elastic contact member, and FIG. 4 is a curved wafer. FIG. 9 is an explanatory view for explaining the curvature correction of the curved surface wafer by the vacuum suction table.

In the curved wafer suction table of this embodiment,
As shown in FIGS. 1 and 2, the suction table body 1, the elastic contact member 2, the elastic contact member placement recess 3, the exhaust hole 4, the collective exhaust recess 5, the O-ring 6, the lateral hole 7, the plug 8, the exhaust. Mouth 9, air supply port 1
It has 0. The curved wafer 11 is placed on the curved wafer suction table.

Next, the individual constructions of the curved wafer suction table will be briefly described. The suction table body 1 is in the shape of a rotating body, and its cross section is formed in a substantially concave shape. The suction table body 1 is cut using, for example, a mechanical material of aluminum alloy.

An elastic contact member 2 is provided on the upper surface of the suction table body 1.
Are placed. The elastic contact member 2 is placed in the groove of the elastic contact member placement recess 3. The elastic contact body 2 is formed in a substantially D-shaped annular body as shown in FIG. In addition to this, the elastic contact member 2 formed in an annular shape may be fitted into the elastic contact member arranging concave portion 3 to be deformed into a substantially D-shaped annular member. In any case, it is used in the form as shown in FIG.
As shown in FIGS. 1, 2 and 3 (b), the elastic contact member 2 has a groove 2a formed on the upper side, and therefore has a substantially concave cross section. Further, as shown in FIGS. 1, 2 and 3 (b), a plurality of (for example, eight) hole portions 2b are formed in the groove portion 2a. These holes 2b communicate from the lower side of the elastic contact member 2 to the upper groove 2b. The elastic contact body 2 is
Preferably, the material is chloroprene rubber having a hardness of 45.

The elastic contact member arranging recess 3 is substantially D-shaped and is substantially the same as the elastic contact member 2 so that the elastic contact member 2 which is an annular body or a substantially D-shaped annular member can be arranged. A groove formed in the suction table body 1 so as to have an annular shape, and as shown in FIG. 3 (a), the groove bottom surface 3 a has a low inner peripheral side groove bottom surface 3 a and a high outer peripheral side groove bottom surface 3 b. Are formed in multiple stages. In order to adopt such a configuration,
Elastic contact member 2 disposed in the elastic contact member placement recess 3
3B, as shown in FIG. 3B, the suction table body 1 is inclined downward from the outer peripheral side toward the inner peripheral side along the radial direction.
Will be placed in.

In addition to forming the groove bottoms in multiple steps so that the inner groove bottom 3a is low and the outer groove bottom 3b is high, for example, a step is formed on the groove bottom of the elastic contact member placement recess 3. Even if a substantially D-shaped annular body (for example, a wire formed in a substantially D shape) that is in close contact with only the outer peripheral side of the groove is arranged without providing the elastic contact body 2, the elastic contact body 2 is shown in FIG. 3B. Thus, the suction table body 1 is arranged so as to incline downward from the outer peripheral side toward the inner peripheral side along the radial direction. Although such a configuration is appropriately selected, the suction table body 1
Since it can be formed at one time during the cutting process, it is preferable to employ the recessed portion 3 for arranging the elastic contact body having a multi-stage bottom portion.

Exhaust holes 4 are provided below the plurality of holes 2b of the elastic contact member 2, respectively. For example, if there are eight holes 2b, eight exhaust holes 4 will be provided substantially below the holes 2. As shown in FIG. 1, the back surface of the suction table body 1 is provided with a collective exhaust recess 5 which is an annular groove. The collective exhaust recess 5 is connected to the hole 2b through the plurality of exhaust holes 4 and the elastic contact member placement recess 3. It should be noted that the collective exhaust recess 5 needs to be located below all the holes 2b.

An O-ring 6 is arranged below the collective exhaust recess 5. The O-ring 6 is the recess 5 for collective exhaust.
The wire diameter is such that it can be in close contact with and closed by this opening when placed in the opening (see FIG. 1). The O-ring 6 is one specific example of the seal body of the present invention. In addition to the O-ring 6, for example, an elastic ring body having a square cross section, or a resin cured. It may be a sealing member or the like. However, it is preferable to adopt the O-ring 6 from the viewpoint of easy handling and cost.

A lateral hole 7 communicates with the collective exhaust recess 5. This lateral hole 7 is formed by a drilling machine so that it reaches the collective exhaust recess 5 from the right side shown in FIG. 1 during machining. This lateral hole 7 is sealed by a plug 8. At the time of this sealing, a female screw portion is provided in the lateral hole 7,
The plug 8 that is a male screw may be screwed and fixed.

The lateral hole 7 communicates with the exhaust port 9. The exhaust port 9 is connected to a vacuum pump (not shown).
In the present embodiment, the exhaust port 9 has a connector for connecting a vinyl tube so that the exhaust port 9 can be easily connected to the vacuum pump, but the exhaust port 9 may be any port for exhaust, and may be appropriately selected according to the actual condition. It is possible to

An air supply port 10 is further provided at the lower central portion of the suction table body 1. The air supply port 10 communicates with the upper central portion of the suction table body 1. When the curved wafer 11 is placed on such a curved wafer suction table,
As shown in FIG. 1, a closed space 12 is formed by the suction table body 1, the elastic contact member 2 and the curved wafer 11.

Next, suction of a curved wafer by the curved wafer suction platform having such a structure will be described. When the curved wafer 11 is placed on the curved wafer suction table as shown in FIG. 1, as shown in FIG.
The curved wafer 11 contacts on the outer peripheral side of the elastic contact member 2.
Before the vacuum suction operation, there may be some clearance at this contact portion, but the curved wafer 11 is almost in contact with the elastic contact member 2 due to its own weight.

In some cases, the curved wafer 11 and the elastic contact member 2 have the same inclination, and as shown in FIG. 3 (d), the elastic contact member 2 may adhere to the inner peripheral side and the outer peripheral side. Usually, before the vacuum suction operation, as shown in FIG. 3C, there is often a slight gap on the inner peripheral side of the curved wafer 11.

In this state, a vacuum pump (not shown) is operated to start exhausting. Air is groove 2a, hole 2
b, the elastic contact member arranging concave portion 3, the exhaust hole 4, the collective exhaust concave portion 5, the lateral hole 7, and the exhaust port 9. In this case, since the O-ring 6 is sucked into the collective exhaust recess 5, the O-ring 6 is more surely brought into close contact. Immediately after the start of exhaust,
As shown in FIG. 3C, air also flows in from the closed space 12, but as the exhaust proceeds, the curved wafer 11 descends, and eventually the elastic contact member 2 as shown in FIG. 3D.
The curved wafer 11 adheres to the inner and outer peripheries.

In this case, since the elastic contact member 2a is inclined in the left-right direction by the bottom surface portions (the inner peripheral side groove portion 3a and the outer peripheral side groove portion 3b) formed in multiple steps of the groove portion 2a, the inner peripheral side and the outer peripheral side of the groove portion 2a. 3 and the side surface of the elastic contact member 2a firmly come into close contact with each other (see FIG. 3 (d)), which reduces the risk of air leaking from the contact surface between the elastic contact member 2 and the groove 2a. It becomes easier to maintain the vacuum state.

Then, an air supply pump (not shown) is operated to supply the air into the closed space 12 through the air supply port 10. Also in this case, the suction operation is continued while the groove portion 2a of the elastic contact member 2 is kept in a vacuum state with a vacuum pump (not shown) being operated. The inside of the closed space 12 expands due to pressure, and as shown in FIG.
As the central part of 1 rises, the outer peripheral part descends,
The curved state of the curved wafer 11 is corrected.

The curved wafer suction table described above can have various configurations other than the above, for example, the groove portion 2a.
The air outlet 9 and the air passage are connected to each other through the hole 2b, the elastic contact member arranging recess 3, the exhaust hole 4, the collective exhaust recess 5, and the lateral hole 7. Besides, various routes can be selected, and at least the groove 2a
It suffices that the path is connected from the hole 2b to the exhaust port 9.

The curved wafer suction table described above has various advantages as follows. (1) A state in which the elastic contact member 2 is firmly adhered to the curved wafer 11 because the point elastic contact member 2 capable of adsorbing the curved wafer 11 is arranged so as to incline downward from the outer peripheral side to the inner peripheral side along the radial direction. It is possible to realize a function that is conventionally impossible, that is, adsorption. Moreover, since the elastic contact member 2 easily comes into close contact with the curved wafer 11,
There are advantages such as fast suction operation and high suction capacity.

(2) Easy to manufacture curved surface wafer suction table As shown in FIG. 1, the suction table body 1 is shaped so that it can be easily processed by cutting with a milling plate, lathe, or the like. Has been adopted. For example, the elastic contact member placement recessed portion 3 and the collective exhaust recessed portion 5 in FIG. 1 can be easily cut by applying an end mill / bite from above and below in FIG. Further, since the elastic contact member arranging concave portion 3 has a substantially D-shaped shape including a linear portion on a plane, it is difficult to process the bottom surface portion into a slope shape, but it is formed in multiple steps as shown in FIG. 3A. Therefore, also in this respect, there is an advantage that the machining can be easily performed by applying the end mill bite from the upper and lower sides of FIG.

(3) Large attraction force Furthermore, the elastic contact member 2 positioned obliquely is shown in FIG.
As shown in (b), (c), and (d), since it firmly adheres to the wall surface of the groove portion, air is surely and easily exhausted from the groove portion 2a, and a vacuum pump having a relatively low cost and a low exhaust capacity is used. However, the adsorption capacity is sufficiently high, which also contributes to cost reduction.

(4) Since a curved wafer is provided with a function of correcting the curvature of the curved wafer 11 by pressurizing the inside of the point closed space 12 having a curvature correction function, the curved wafer 11 is a flat wafer having substantially no curvature. The semiconductor manufacturing process can be performed in the corrected state. In this case, the positioning of the robot or the like that performs various kinds of processing can be performed accurately, and this contributes to the improvement of the yield in this respect as well as the shortening of the positioning time.

[0038]

As described above, according to the present invention,
It is possible to provide a curved wafer suction table that sucks a curved wafer with a simple mechanism.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a curved wafer suction table of the present invention.

FIG. 2 is an explanatory diagram of an elastic contact body.

FIG. 3 is an explanatory diagram of an elastic contact member and a recess for arranging the elastic contact member.

FIG. 4 is an explanatory diagram illustrating correction of curvature of a curved wafer by a curved wafer suction table.

FIG. 5 is an explanatory diagram illustrating a conventional wafer suction table.

[Explanation of symbols]

1 Suction table body 2 Elastic contact 2a groove 2b hole 3 Recess for elastic contact body placement 3a Outer peripheral groove bottom surface 3b Inner peripheral groove bottom 4 exhaust holes 5 Recessed exhaust recess 6 O-ring 7 lateral holes 8 stoppers 9 exhaust port 10 Air supply port 11 curved wafer

Claims (6)

[Claims] 1. A suction table main body, and a substantially D-shaped annular body having a substantially concave cross section, the elasticity being arranged on the suction table main body so as to incline downward from the outside in the radial direction of the ring. A suction table for a curved wafer, comprising: a close contact body, a hole provided on the bottom surface of the groove of the elastic close contact body, and an exhaust port provided on the suction stand body so as to communicate with the hole. 2. The curved wafer suction table according to claim 1, further comprising: an air supply port formed in the suction table main body so as to be located in the ring of the elastic contact member. Suction table. 3. The curved wafer suction table according to claim 1 or 2, wherein the elastic contact member is arranged on the suction table body so as to incline downward from the outer side to the inner side in the radial direction of the ring. Therefore, in the groove formed in the suction table body so as to have a substantially D-shaped annular shape, the groove bottom surface is formed in multiple stages so that the groove bottom surface on the inner peripheral side is low and the groove bottom surface on the outer peripheral side is high. A suction pad for a curved wafer, comprising the formed recess for arranging an elastic contact member. 4. The curved wafer suction table according to claim 1, wherein the elastic contact member is preferably formed of chloroprene rubber having a hardness of 45 as a material. Suction table for curved wafers. 5. The curved wafer suction table according to claim 1, wherein a plurality of holes are provided on the bottom surface of the groove of the elastic contact member, and the elastic contact member is disposed on the surface. A curved wafer suction table, comprising: a collective exhaust recess provided on the back surface of the suction table main body and connected to the plurality of holes; and a seal body for sealing the collective exhaust recess. 6. The curved wafer suction table according to claim 5, wherein the collective exhaust recess is an annular shape, and the sealing body is an O-ring that is in close contact with and closes the opening of the collective exhaust recess. A suction table for curved wafers, which is characterized in that