CN110323169B

CN110323169B - Molding apparatus and method

Info

Publication number: CN110323169B
Application number: CN201810263288.XA
Authority: CN
Inventors: 张瑞堂
Original assignee: Himax Technologies Ltd
Current assignee: Himax Technologies Ltd
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2021-12-21
Anticipated expiration: 2038-03-28
Also published as: CN110323169A

Abstract

A molding device comprises a working mold arranged above a wafer; the vacuum chuck is arranged below the wafer and clamps the wafer by vacuum suction, the vacuum chuck comprises an inner chuck and an outer chuck which can respectively move axially, and the outer chuck surrounds the inner chuck; and the film separating ring is arranged above the edge of the wafer.

Description

Molding apparatus and method

Technical Field

The present invention relates to a molding process, and more particularly, to a wafer molding apparatus and method.

Background

Embossing (repolicalization) is one type of molding process that produces optical elements by transferring the optical surface of a mold (master or mold) to the surface of a wafer (or work piece).

When the imprint process is completed, the wafer must be separated from the mold. The separation (demolding) stage is typically achieved by applying pressure to the edge of the wafer. For 8 inch wafers with a thickness of 0.25 mm, the edge is typically 0.8-3.6 mm. Due to the imbalance (disequibrium) of the wafer surface, the wafer is prone to bow or even crack during the separation stage.

Therefore, a novel mechanism is needed to prevent the wafer from cracking during the separation stage.

Disclosure of Invention

In view of the above, an objective of the embodiments of the present invention is to provide a forming apparatus, in which a vacuum chuck includes an inner chuck and an outer chuck. The present embodiment provides a two-stage method for separating wafers. The forming device and method of the present embodiment can effectively separate the wafer without causing the wafer to break.

According to the embodiment of the invention, the forming device comprises a working mold, a vacuum chuck and a film separating ring. The working die is arranged above the wafer. The vacuum chuck is arranged below the wafer and clamps the wafer by vacuum suction. The vacuum chuck comprises an inner chuck and an outer chuck, which can move axially respectively, and the outer chuck surrounds the inner chuck. The release ring is arranged above the edge of the wafer.

According to another embodiment of the present invention, the inner chuck and the outer chuck respectively apply an inner vacuum suction force and an outer vacuum suction force to the bottom surface of the wafer during the molding process, thereby clamping the wafer, and the outer chuck surrounds the inner chuck. When the wafer is finished with the molding process, the outer chuck is lowered to release the edge of the wafer. A downward pressing force is applied to the edge of the wafer, thereby separating the edge of the wafer from the working mold. The inner chuck is lowered while holding the wafer by the inner vacuum suction force while continuing to apply a pressing force to the edge of the wafer. When the inner sucker reaches the preset position, the inner sucker stops moving.

Drawings

FIG. 1A is a perspective view of a molding apparatus according to an embodiment of the present invention.

FIG. 1B shows a cross-sectional view of the molding apparatus of FIG. 1A.

FIG. 2A is a top view of a lift-off ring disposed over a wafer.

Fig. 2B and 2C show schematic side views of the teeth and the inflation tube.

Fig. 3A to 3C are cross-sectional views of the molding apparatus of fig. 1A, sequentially illustrating a method for molding a wafer according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating a two-stage wafer forming method according to an embodiment of the present invention.

FIG. 5A illustrates a schematic diagram of applying a force to a wafer corresponding to step 41 of FIG. 4 and FIG. 3A.

FIG. 5B illustrates a schematic diagram of applying force to the wafer corresponding to step 42 of FIG. 4 and FIG. 3B.

Detailed Description

Fig. 1A shows a perspective view of a molding apparatus 100 according to an embodiment of the present invention, and fig. 1B shows a cross-sectional view of the molding apparatus 100 of fig. 1A. In the present embodiment, the molding apparatus 100 may be a stamping (replication) machine for performing a stamping process to manufacture an optical element by transferring an optical surface of a working mold (master) to a surface of a wafer 12, wherein the working mold 11 is disposed in a holder 10 and above the wafer 12.

The molding apparatus 100 of the present embodiment may include a vacuum chuck (vacuum chuck)13 disposed below the wafer 12 for holding the wafer 12 by vacuum suction. According to one feature of this embodiment, the vacuum chuck 13 may comprise at least two components: an inner suction cup 13A and an outer suction cup 13B, wherein the outer suction cup 13B surrounds the inner suction cup 13A. The inner suction cup 13A and the outer suction cup 13B are movable in the axial direction (upward or downward), respectively. The inner chuck 13A of the present embodiment may include a (circular) disk 131A having a flat surface for securely holding the wafer 12 and an inner support 132A for supporting the disk 131A. The outer chuck 13B of the present embodiment may include a ring 131B having a flat surface for stably holding the wafer 12 and a plurality of outer legs 132B for supporting the ring 131B.

The molding apparatus 100 of the present embodiment may include a separating ring (separating ring)14 disposed above the edge of the wafer 12. Fig. 2A shows a top view of lift-off ring 14 disposed over wafer 12. When the wafer 12 is finished with the molding process and is about to be separated from the working mold 11, the stripper ring 14 moves downward to apply a (downward) pressing force to the wafer 12 for separating the wafer 12 from the working mold 11. As shown in fig. 1B and fig. 2A, the plurality of teeth 15 (disposed above the membrane separation ring 14) are pressed by an inflating tube (inflating tube)16, so that the membrane separation ring 14 moves downward, wherein the inflating tube 16 is disposed below the first ends of the teeth 15. Although fig. 2A illustrates four teeth 15, the number of teeth 15 may be greater than four.

Fig. 2B and 2C show side views of the teeth 15 and the gas-filling tube 16. As shown in fig. 2B, the first intermediate member 17A and the second intermediate member 17B are disposed between the gas-filled tube 16 and the tooth 15 from bottom to top. The first intermediate member 17A may be of plastic material and the second intermediate member 17B may be of iron material. In the deflated state shown in fig. 2B, the inflation tube 16 is deflated and the teeth 15 are not compressed. In other words, the deflated inflation tube 16 does not apply a force to the first end (e.g., the left end or the outer end) of the tooth 15 via the first intermediate element 17A and the second intermediate element 17B. In the inflated state shown in fig. 2C, the inflation tube 16 is inflated and the teeth 15 are forced. In other words, the inflated inflation tube 16 applies a force to the first end of the tooth 15 via the first intermediate element 17A and the second intermediate element 17B. The tooth 15 acts as a lever with its pivot (pivot) between a first end and an opposite second end (e.g., a right or inner end). Thereby, the second end of the tooth-like member 15 moves downward and applies a force to the separation ring 14. In other embodiments, a mechanism other than the teeth 15 and the inflation tube 16 may be used to move the membrane ring 14 down.

Fig. 3A to 3C are cross-sectional views of the forming apparatus 100 of fig. 1A, sequentially illustrating a method of forming the wafer 12 according to an embodiment of the present invention. Fig. 4 shows a flowchart of a two-stage molding method 400 for a wafer 12 according to an embodiment of the invention, which corresponds to the cross-sectional views illustrated in fig. 3A to 3C.

Referring to fig. 3A, in step 41, the vacuum chuck 13 includes an inner chuck 13A and an outer chuck 13B, and an inner vacuum suction force and an outer vacuum suction force are respectively applied to the bottom surface of the wafer 12 during a molding process (e.g., imprinting), thereby clamping the wafer 12. FIG. 5A illustrates a schematic diagram of applying a force to the wafer 12 corresponding to step 41 of FIG. 4 and FIG. 3A.

Referring to fig. 3B, at step 42 (i.e., the first stage), when the wafer 12 is finished with the molding process, the outer chuck 13B is lowered to release the edge of the wafer 12. At the same time (or thereafter), the stripper ring 14 applies a (downward) pressing force to the edge of the wafer 12, thereby separating the edge of the wafer 12 from the working mold 12. Fig. 5B shows a schematic diagram of applying force to the wafer 12 corresponding to step 42 of fig. 4 and fig. 3B.

Referring to fig. 3C, at step 43 (i.e., the second stage), the inner chuck 13A is lowered but still holds the wafer 12 by the inner vacuum suction while the stripper ring 14 continues to apply (downward) pressure to the edge of the wafer 12. In the present embodiment, the inner sucker 13A descends at a speed (e.g., 0.5 mm/sec) smaller than the descending speed (e.g., 1 mm/sec) of the off-membrane ring 14. At step 43 and step 42, the sum of the forces applied to the wafer 12 is substantially equal, as shown in FIG. 5B. At step 43, since the peeling ring 14 continuously applies (downward) pressing force to the top surface of the edge of the wafer 12 and the inner suction plate 13A simultaneously holds the wafer 12 by the inner vacuum suction force, the wafer 12 is prevented from being broken due to the bending. Finally, in step 44, when the inner chuck 13A reaches the predetermined position, the movement of the inner chuck 13A and the off-film ring 14 is stopped.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; other equivalent changes and modifications without departing from the spirit of the disclosure are intended to be included within the scope of the following claims.

Description of the symbols:

100 molding apparatus

10 support

11 working die

12 wafer

13 vacuum chuck

13A inner suction disc

131A disc

132A internal support

13B external suction disc

131B ring

132B outer support

14 separating membrane ring

15 tooth-like piece

16 inflation tube

17A first intermediate element

17B second intermediate element

41 vacuum chuck for clamping wafer

42 lower the outer chuck and apply force to the edge of the wafer

43 lower the inner chuck and apply force to the edge of the wafer

The suction disc stops at 44.

Claims

1. A molding device comprises a working mold, a vacuum chuck and a film separating ring:

the working die is arranged above the wafer;

the vacuum chuck is arranged below the wafer and clamps the wafer by vacuum suction, the vacuum chuck comprises an inner chuck and an outer chuck which can respectively move axially, and the outer chuck surrounds the inner chuck; and

the film separating ring is arranged above the edge of the wafer,

wherein when the wafer is finished with the forming process, the outer chuck is lowered to release the edge of the wafer, and the stripper ring is moved down to apply a pressing force to the wafer to separate the wafer from the working mold, and thereafter, the inner chuck is lowered while holding the wafer while the stripper ring continues to apply the pressing force to the edge of the wafer, and wherein the inner chuck is lowered at a speed less than the pressing speed of the edge of the wafer.

2. The molding apparatus as defined in claim 1, wherein the inner chuck comprises:

a plate having a flat surface to hold the wafer; and

an inner support for supporting the disc.

3. The molding apparatus as defined in claim 1, wherein the outer chuck comprises:

a ring having a flat surface to hold the wafer; and

a plurality of outer struts to support the ring.

4. The molding apparatus as defined in claim 1, further comprising:

and the tooth-shaped pieces are arranged above the membrane separating ring and used for pressing the membrane separating ring to move downwards.

5. The molding apparatus as defined in claim 4, further comprising:

and the inflation tubes are respectively arranged below the first ends of the toothed pieces.

6. The molding apparatus as defined in claim 5, further comprising:

the first middle element and the second middle element are arranged between the inflation tube and the tooth-shaped piece from bottom to top,

when the inflation tube is in an inflation state, the inflated inflation tube applies force to the first end of the tooth-shaped member through the first intermediate element and the second intermediate element, so that the second end of the tooth-shaped member moves downwards to apply force to the membrane separation ring.

7. A method of forming, comprising:

when the inner sucker and the outer sucker are in a forming process, the inner vacuum suction force and the outer vacuum suction force are respectively applied to the bottom surface of the wafer, so that the wafer is clamped, and the outer sucker surrounds the inner sucker;

when the wafer finishes the forming process, the outer sucker descends so as to release the edge of the wafer;

applying a downward pressing force to the edge of the wafer, thereby separating the edge of the wafer from the working mold;

the inner sucker descends but still clamps the wafer by inner vacuum suction force, and simultaneously continuously exerts pressing force on the edge of the wafer; and

when the inner sucker reaches a preset position, the movement of the inner sucker is stopped,

wherein the inner sucker descends at a speed lower than the pressing speed of the edge of the wafer.

8. The method of claim 7, wherein the pressing force applied to the edge of the wafer is provided by a stripper ring disposed over the edge of the wafer.

9. The molding method of claim 8, further comprising:

and a plurality of tooth-shaped pieces are used for pressing the membrane separating ring to move downwards, and the tooth-shaped pieces are arranged above the membrane separating ring.

10. The molding method of claim 9, further comprising:

and applying force to the first end of the tooth-shaped piece to enable the second end of the tooth-shaped piece to move downwards, so that the force is applied to the film separating ring.

11. The method of claim 10, wherein the force applied to the first end of the tooth is generated by a gas tube disposed below the first end of the tooth.