JPH10209247A - Chucking device of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely adsorb a thin wafer and hold it so that it may be not cracked even when it is chucked by the sucking action at the time of transfer and the wafer may be quickly and surely separated when the sucking action is released in a chucking device which chucks and transfers the semiconductor wafer. SOLUTION: This is a chucking device to be used at the time of transferring a semiconductor wafer and the semiconductor wafer has a flat chucking face sucking and holding the semiconductor wafer and suction region 28 is formed on the suction region 28 and a non-suction region 29 is formed on its outer periphery and a plurality of unevenness are formed on the suction face. Even in the case of a substrate of a chucking type on the whole surface of the wafer, no influence of surface tension such as cutting water is excerted due to a plurality of formed unevenness, thus allowing sure separation of the wafer when the sucking action is cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying a material such as a semiconductor wafer having a plurality of circuits, such as ICs, formed on a front surface thereof to a polishing apparatus and polishing the back surface of the semiconductor wafer with a grinding wheel or the like. Further, the present invention relates to a semiconductor wafer suction device which is used by being attached to a transport means engaged in the supply.

[0002]

2. Description of the Related Art In recent years, semiconductor wafers having a plurality of circuits, such as ICs, formed on the front surface thereof have tended to have a large diameter of 8 inches and 12 inches, improved heat dissipation, mobile communication and portable personal computers. In order to reduce the weight and size of such devices, it is desired that the devices be formed thinner (around 200 μm). Before the semiconductor wafer is divided into chips, the back surface is shown in FIG. The polishing is performed by such an example of the polishing apparatus 1.

The polishing apparatus 1 of this example includes a turntable 3 rotatably disposed on a work table 2, a chuck table 5 disposed on the turntable 3 to hold two or more semiconductor wafers 4, and A plurality of polishing means 7 provided with a polishing grindstone 6 for polishing the semiconductor wafer 4 in opposition to the chuck table 5.

The turntable 3 is rotatably driven by an appropriate control means to position the chuck table 5 in the wafer loading / unloading area A and to position the chuck table 5 in the polishing area B for polishing the wafer 4. I have. Then, when the chuck table 5 is positioned in the wafer loading / unloading area A by the rotation of the turntable 3, the supply and unloading of the wafers 4 are performed by the transfer means 8, and when the chuck table 5 is positioned in the polishing area B, The back surface of the wafer 4 held on the chuck table 5 is
To a required thickness.

In the vicinity where the transfer means 8 is provided, a temporary receiving table 9 having a cleaning function and an alignment table 10 are provided, and the wafer 4 is placed on the alignment table 10. Take out from cassette 11 and place,
Alternatively, a robot arm 12 that picks up the wafer 4 from the alignment table 10 and places it on the cassette 11 is provided.

[0006] At the front end of the transfer means 8, a suction means 13 for sucking and picking up the wafer 4 is attached. A typical conventional suction means is a so-called suction disk type Bernoulli chuck or a rubber pad chuck widely known in the art.

According to the suction means of the suction disk type, the suction force is concentrated on the central portion of the wafer. Therefore, if the size of the wafer is increased and the wafer is polished thinly, the wafer tends to be broken during transportation. Have.

[0008]

What solved this problem is the invention disclosed in Japanese Patent Application Laid-Open No. 8-55896 filed by the same applicant, that is, a conveying means of the type in which the entire surface of the adsorption means is adsorbed. . However, the suction means of the type that performs suction on the entire surface has a new problem on the flat outer peripheral surface where the suction action does not occur. That is, cutting water or the like exists on one surface between the flat surface of the outer circumference and the sucked wafer, and the surface tension of the cutting water causes a close contact or suction action different from the suction action, thereby causing the suction action of the suction means. Even after the wafer is opened, a phenomenon that the wafer does not separate from the suction means often occurs, which hinders the workability of the transfer, and causes a problem that a thin wafer is easily broken when trying to forcibly separate it.

Therefore, the suction means or the suction apparatus of the prior art can reliably suck the wafer so as not to be broken by the suction action, and can surely release the wafer when the suction action is released. Have challenges to do.

[0010]

As a specific means for solving the problems of the prior art, the present invention relates to a suction device used for transporting a semiconductor wafer, wherein the suction device has a flat surface for holding the semiconductor wafer by suction. It has an adsorption surface, and the adsorption surface has
A suction region and a non-suction region are formed around the suction region,
An object of the present invention is to provide a semiconductor wafer suction device, wherein a plurality of irregularities are formed in the non-suction region.

[0011] Further, the suction area is formed of a porous member, and the non-suction area is formed of ceramics;
A suction hole is formed in a part of the recess;
And the like are provided as an additional requirement that the circuit is disposed in a polishing apparatus for polishing a back surface of a semiconductor wafer formed on a plurality of surfaces.

In the suction device of the present invention, even if the suction device is of a type in which the wafer is suctioned over the entire surface, the influence of the surface tension of cutting water or the like is formed by forming a plurality of irregularities in the non-suction region on the outer periphery. Therefore, the wafer can be reliably and promptly released when the suction action is released.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the illustrated embodiments. First, in the first embodiment shown in FIGS.
Is attached to the top of a disk-shaped base 21 made of, for example, ceramics.
Are formed, and a plurality of mounting portions 2 are provided around the mounting portion.
3, 24 and 25 are appropriately formed.

Each of the mounting portions 22 to 25 is formed of, for example, a metal bush in order to provide a predetermined strength because it is mounted on the arm of the transporting means. 22a to 25a are formed. And each mounting part, ie, bush 22 ~
Reference numeral 25 is a member which is firmly attached to a required hole provided in the base 21 by, for example, an adhesive means. still,
When the base 21 is made of metal, the mounting portions 22 to 25 can be appropriately formed at predetermined positions of the base 21 without the need for a bush or the like.

On the lower surface (back surface) side of the base 21, a suction surface constituting member 26 of substantially the same shape (disk shape) is integrally attached. The suction surface constituting member 26 can be formed of, for example, ceramics, and is integrally attached to the base 21 by an adhesive means or the like. A plurality of shallow groove-shaped gaps 27 are formed between the base 21 and the suction surface constituting member 26 along the circumferential direction.
Is in communication with a screw hole 22a formed in the mounting portion 22 at the center.

The lower surface of the suction surface constituting member 26 is formed as a flat suction surface, and the suction surface is divided into a suction area 28 and a non-suction area 29. In this case, the suction region 28 is a circular region having a predetermined width from the center, and the non-suction region 29 is a narrow ring-shaped region located on the outer periphery. The groove-shaped gap 27 is formed at a position corresponding to the suction area 28.

As shown in FIGS. 4 and 5, the suction area 28 has a plurality of dot-shaped protrusions 30 formed on the suction surface at predetermined intervals, and the space between the dot-shaped protrusions 30 is substantially formed. The recess 31 is formed. Therefore, a plurality of uneven portions are formed on the suction surface of the suction region 28.

A plurality of suction holes 32 are formed in the concave portion 31 of the suction surface and communicate with the groove-shaped void portion 27. The concave portion 31 on the suction surface is maintained in a reduced pressure state through the suction hole 32. This holds the semiconductor wafer 4 by suction.

In the non-suction region 29, a lattice-shaped groove 33 is formed on the entire surface, and the formation of the groove 33 defines a convex portion 34. The groove 33 and the convex portion 34 substantially form a plurality of irregularities. The portion will be formed in the non-suction region 29.

In the non-suction region 29 formed as described above, the presence of the concave and convex portions destroys the surface tension of the cutting water or the like, so that the cutting water or the like temporarily exists on the surface of the semiconductor wafer 4 to be adsorbed. Can also block the effect of surface tension.

FIGS. 6 to 9 show a suction apparatus 20 according to a second embodiment. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals and described. This adsorption device 2
Reference numeral 0 is also attached to the tip of the conveying means 8 of the conventional example, and a suction means is provided at the center on the upper surface side of a disk-shaped base 21 formed of, for example, ceramics to a predetermined thickness. An attachment portion 22 for the transporting means 8 also serving as the attachment portion is formed.
Further, a plurality of mounting portions 23, 24, 2
5 is appropriately formed.

The mounting portions 22 to 25 are formed by, for example, metal bushes in order to provide a predetermined strength because they are mounted on the arms of the transporting means. 22a to 25a are formed. And each mounting part, ie, bush 22 ~
Reference numeral 25 is a member which is firmly attached to a required hole provided in the base 21 by, for example, an adhesive means. These components are substantially the same as those of the first embodiment.

The lower surface (back surface) side of the base 21 is formed in a state where a circular concave portion 35 having a predetermined size is cut off at the center, as is clear from the partially cutaway view of FIG. Recess 3
A material having air permeability, for example, a porous member 36 is fitted and attached in 5, and a region where the porous member 36 is attached is a so-called suction region 28. Therefore,
The ring-shaped portion left on the outer periphery of the circular concave portion 35 becomes the non-suction region 29, and the non-suction region 29 is constituted by a part of the base 21.

The porous member 36 to be attached is formed in advance in accordance with the shape, size and depth of the concave portion 35, and the porous member 36 is fitted into the concave portion 35, and is integrally formed by, for example, an appropriate bonding means. Attach it. Then, processing is performed so that the suction area 28 and the non-suction area 29 constituting the suction surface are substantially flush.

A plurality of shallow groove-shaped gaps 27 are formed along the circumferential direction between the attached porous member 36 and the recess 35, and these groove-shaped gaps 27 are attached at the center. It is in a state of communicating with a screw hole 22 a formed in the part 22. This configuration is the same as in the first embodiment.

Also in the second embodiment, the non-suction region 2
9, a plurality of linear groove groups 37 are formed in different directions along the tangential direction of the arc of the concave portion 35, and by forming the groove group 37, a portion without the groove group is substantially formed. Therefore, a plurality of uneven portions are formed in the non-suction region 29.

In the non-suction region 29 formed in this manner, as in the first embodiment, the surface tension of cutting water or the like is destroyed by the presence of the uneven portions, so that the surface of the semiconductor wafer 4 temporarily adsorbed is formed. Even if cutting water is present in the
The effect of the surface tension can be cut off.

The suction device 20 in any of the above embodiments
Can also be used as the suction means 13 of the transport means 8 in the polishing apparatus 1 shown in FIG. 10, and in particular, the semiconductor wafer 4 is polished by the polishing means 7 while supplying a polishing liquid or grinding water. Later, in the wafer loading / unloading area A, when picking up the wafer 4 from the chuck table 5 by the transfer means 8, the suction device 20 is positioned close to the chuck table 5;
When the wafer 4 is sucked through the suction hole 22 a by an appropriate suction means, the wafer 4 is sucked by the suction area 28 and is picked up while being in contact with the entire suction surface of the suction device 20.

In general, before the polished wafer 4 arrives at the wafer carry-in / out area A, moisture and dirt are wiped off by air spray or the like, but even if water droplets or the like remain on the surface of the wafer 4, Since the transfer operation is performed, particularly when suction is performed by the suction device 20,
In the non-sucking area 29, the unevenness prevents the spread of water droplets and destroys the surface tension of water, so that the non-adsorption area 29 is not affected by surface tension.

Therefore, after the wafer 4 is suctioned by the suction device 20, if the wafer 4 is conveyed to a predetermined position and the suction force in the suction area 28 is released, the wafer 4 is immediately separated and placed at the predetermined position. Further, if a water droplet is present in the adsorption area 28, it is removed by suction with a suction force, so that there is no influence of the surface tension due to the water droplet or the like. In the above-described embodiment, an example in which the polishing apparatus 1 is used by being attached to the transporting means 8 of the polishing apparatus 1 has been described.

[0031]

As described above, the semiconductor wafer suction device according to the present invention is a suction device used for transporting a semiconductor wafer, and has a flat suction surface for sucking and holding the semiconductor wafer. The suction surface has a suction area and a non-suction area formed on the outer periphery of the suction area, and the non-suction area has a plurality of irregularities. In this way, the surface tension of the water droplet can be destroyed and its influence can be cut off. And an excellent effect that the inconvenience of not being detached even after canceling can be solved.

[Brief description of the drawings]

FIG. 1 is a plan view of a suction device according to a first embodiment of the present invention.

FIG. 2 is a bottom view in which a part of the suction device of the embodiment is cut away.

FIG. 3 is a schematic sectional view taken along line CC of FIG. 2;

FIG. 4 is an enlarged sectional view of a portion indicated by D in FIG. 3;

FIG. 5 is a bottom view of the enlarged portion shown in FIG. 4;

FIG. 6 is a plan view of a suction device according to a second embodiment of the present invention.

FIG. 7 is a bottom view in which a part of the suction device of the embodiment is cut away.

FIG. 8 is a schematic sectional view taken along line EE of FIG. 6;

FIG. 9 is an enlarged sectional view of a portion indicated by F in FIG. 8;

FIG. 10 is a schematic perspective view of an example of a generally used polishing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polishing apparatus, 2 ... Work table, 3 ... Turntable, 4 ... Semiconductor wafer, 5 ... Chuck table, 6 ... Polishing whetstone, 7 ... Polishing means, 8 ... Transport means, 9 ... ... Temporary support, 10 ... Positioning table,
11: cassette, 12: robot arm, 13
... Suction means, A ... Wafer loading / unloading area, B ...
Polishing area, 20: suction device, 21: base, 22
-25: mounting portion, 22a: screw hole also serving as suction hole,
23a to 25a: screw holes, 26: suction surface constituent members, 27: groove-shaped voids, 28: suction areas, 29
... non-suction area, 30 ... point-like convex part, 31, 34 ...
... recess, 32 ... suction hole, 33 ... groove, 35 ...
Recessed portion, 36: porous member, 37: groove group.

Claims (4)

[Claims] 1. A suction device used for transporting a semiconductor wafer, comprising a flat suction surface for sucking and holding the semiconductor wafer, wherein the suction surface has a suction region and a non-suction region on the outer periphery thereof. Wherein a plurality of irregularities are formed in the non-suction region. 2. The semiconductor wafer suction device according to claim 1, wherein the suction region is formed of a porous member, and the non-suction region is formed of ceramics. 3. The semiconductor wafer suction apparatus according to claim 1, wherein a plurality of concave and convex portions are formed in the suction region, and suction holes are formed in some of the concave portions. 4. The suction apparatus according to claim 1, wherein a circuit such as an IC is provided in a polishing apparatus for polishing a back surface of a semiconductor wafer having a plurality of circuits formed on the front surface.