JP2016066763A - Method for forming etching mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an etching mask, by which an etching mask can be formed by a more simplified combination of steps without using a photomask in comparison to conventional ones.SOLUTION: A method for forming an etching mask (27) comprises: a preparation step for preparing a plate-like mold member (21) in which a concave portion (23) corresponding to each non-etching region of a workpiece (11) is formed; a liquid-resist supplying step for filling the concave portion of the mold member with a liquid resist (25); a workpiece-setting step for putting the workpiece on the mold member in a state where the concave portion is opposed to the non-etching region, thereby bringing the liquid resist in the concave portion into contact with the non-etching region; a liquid resist-curing step for stimulating and curing the liquid resist, thereby forming the etching mask (27); and a workpiece peeling step for peeling the workpiece from the mold member.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for forming an etching mask that serves as a protective member when a plate-like workpiece is processed by etching.

  For example, a semiconductor wafer in which devices such as ICs are formed in a plurality of areas on the front surface side divided by dividing lines called streets is ground on the back surface, and then is divided into a plurality of chips corresponding to each device. Divided and incorporated into electronic devices.

  When dividing a plate-shaped workpiece such as a semiconductor wafer, for example, a cutting blade rotating at a high speed is cut into a planned dividing line of the workpiece, and then the cutting blade and the workpiece are divided. Move relative to the planned line. However, in this method, since the workpiece is mechanically scraped along the line to be divided, the bending strength of the tip tends to be lowered.

  Further, in this method, since the cutting blade needs to be positioned with high precision with respect to the division line, and each division line needs to be cut individually, it takes a long time to finish the machining. . This problem is particularly serious in a workpiece having a large number of division lines to be cut.

  Therefore, in recent years, a method of dividing a workpiece using plasma etching has been proposed (see, for example, Patent Document 1). In this method, the entire surface of the wafer can be processed at once by plasma etching. Therefore, even if the number of division lines to be processed increases due to downsizing of the chip, upsizing of the workpiece, etc., the time required for the processing is almost the same. You do n’t have to.

  Further, since the workpiece is not mechanically scraped off, chipping during processing can be suppressed and the bending strength of the chip can be maintained high. In this method, an etching mask serving as a protective member is formed on the surface of the workpiece using a photomask on which a desired light-shielding pattern is formed.

JP 2006-114825 A

  However, the photomask described above is manufactured through complicated processes such as formation of a light shielding film, coating of a resist film, pattern drawing of the resist film, and etching of the light shielding film, and is expensive. Further, when forming an etching mask as a protective member using this photomask, the entire surface of the workpiece is covered with a photoresist film, and then the photoresist film is exposed and developed to form a workpiece. It is necessary to expose the region to be etched.

  As described above, the conventional method for forming an etching mask has a problem that the process is complicated and the processing cost cannot be sufficiently reduced. The present invention has been made in view of such problems, and an object of the present invention is to provide an etching mask forming method capable of forming an etching mask by a simpler process than before without using a photomask. It is.

  According to the present invention, there is provided a method of forming an etching mask that covers an unetched region of a workpiece having an etched region and a non-etched region partitioned by the etched region on a surface, the non-etched region of the workpiece being A preparing step of preparing a plate-shaped mold member having a mounting surface of a size to cover and having a recess having the same size as the non-etching region formed at a position corresponding to the non-etching region of the mounting surface; A resist solution supplying step of supplying a resist solution that is cured by an external stimulus to the concave portion of the mold member and filling the concave portion with the resist solution; and the mounting surface of the mold member and the surface of the workpiece are opposed to each other. A workpiece placing step of placing the workpiece on the mold member in a state where the recess and the non-etching region correspond to each other, and bringing the resist solution filling the recess into contact with the non-etching region; Add to material A resist solution curing step in which an external stimulus is applied to the resist solution in a state where an object is placed to cure the resist solution to form an etching mask attached to the non-etched region, and after the resist solution curing step, the surface And a workpiece peeling step for peeling the workpiece on which the etching mask is formed from the mold member. A method for forming an etching mask is provided.

  In the present invention, it is preferable to apply heat as the external stimulus using the thermosetting resist solution.

  In the present invention, the inner surface of the recess is preferably coated with a material that prevents adhesion of the cured resist solution.

  The method for forming an etching mask according to the present invention uses a plate-shaped mold member in which a recess corresponding to a non-etched region of a workpiece is formed, fills the recess with an etching solution, and then overlaps with the workpiece. Since the liquid is cured, an etching mask can be formed by a simpler process than before without using an expensive photomask.

It is a perspective view which shows typically the structural example of a to-be-processed object. It is a perspective view for demonstrating a preparatory process. It is a perspective view for demonstrating a resist liquid supply process. It is a perspective view for demonstrating a workpiece mounting process. It is a perspective view for demonstrating a resist liquid hardening process. It is a perspective view for demonstrating a workpiece peeling process.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The etching mask forming method according to the present embodiment includes a preparation step (see FIG. 2), a resist solution supplying step (see FIG. 3), a workpiece placing step (see FIG. 4), and a resist solution curing step (see FIG. 5). ), And a workpiece peeling step (see FIG. 6).

  In the preparation step, a plate-shaped mold member having a recess corresponding to the non-etching region of the workpiece on the mounting surface side on which the workpiece is placed is prepared. In the resist solution supplying step, the concave portion of the mold member is filled with a resist solution that hardens when a stimulus is applied. In the workpiece placing step, the workpiece is placed on the mold member in a state where the concave portion and the non-etched region correspond to each other, and the resist solution in the concave portion is brought into contact with the etched region.

  In the resist solution curing step, the resist solution is cured by applying a stimulus to form an etching mask that covers the non-etched region. In the workpiece peeling step, the workpiece is peeled from the mold member. Hereinafter, a method for forming an etching mask according to the present embodiment will be described in detail.

  First, a workpiece for forming an etching mask in this embodiment will be described. FIG. 1 is a perspective view schematically showing a configuration example of a workpiece. As shown in FIG. 1, the workpiece 11 of the present embodiment is a disk-shaped wafer made of a material such as silicon, and the surface 11a is divided lines (streets) 13 arranged in a lattice pattern. It is partitioned into multiple areas.

  This division | segmentation scheduled line 13 becomes an etching area | region processed by an etching. On the other hand, the plurality of regions divided by the division lines 13 are non-etched regions that are not processed by etching. A device 15 such as an IC is formed in each non-etched region.

  In the method for forming an etching mask according to the present embodiment, first, a preparatory step of preparing a plate-shaped mold member having a recess corresponding to the non-etched region of the workpiece 11 is performed. FIG. 2 is a perspective view for explaining the preparation process.

  As shown in FIG. 2, the mold member 21 is formed in a disk shape having substantially the same diameter as the workpiece 11, and includes a mounting surface (surface) 21 a having a size covering all the non-etched regions described above. ing. On the mounting surface 21 a side of the mold member 21, a plurality of recesses 23 having openings having the same size and shape as each non-etched region are formed.

  Each recess 23 is formed at a position corresponding to the non-etched region of the workpiece 11. Although the depth of the recessed part 23 is arbitrary, it is preferable to set it as about 10 micrometers-20 micrometers, for example. The mold member 21 is formed, for example, by processing a wafer, a semiconductor substrate, a glass substrate, a metal substrate, a resin substrate (resin film) or the like equivalent to the workpiece 11 by a method such as etching. Of course, you may form the mold member 21 provided with the recessed part 23 by methods, such as injection molding.

  Moreover, it is preferable to coat a material such as a fluorine-based resin on the mounting surface 21 a side of the mold member 21, particularly on the inner surface of the recess 23. As a result, as will be described later, the etching mask cured with the resist solution is prevented from adhering to the mold member 21, and the etching mask can be easily separated from the mold member 21.

  After the preparation step, a resist solution supplying step for filling the concave portion 23 of the mold member 21 with the resist solution is performed. FIG. 3 is a perspective view for explaining the resist solution supplying step. The resist solution supply step is performed by, for example, the supply device 2 shown in FIG. The supply device 2 includes a nozzle 4 that supplies the resist solution 25 to the concave portion 23 of the mold member 21.

  In the resist solution supply step, the resist solution 25 is supplied from the nozzle 4 to the recess 23 of the mold member 21. The supply amount of the resist solution 25 is controlled, for example, so that the liquid surface of the resist solution 25 is substantially flush with the mounting surface 21 a of the mold member 21.

  As the resist solution 25, for example, a thermosetting resin resistant to subsequent etching is used. However, the resist solution 25 may be cured by a stimulus other than heat (external stimulus). For example, when the mold member 21 transmits light, a photocurable resin can be used as the resist solution 25.

  After the resist solution supplying step, a workpiece placing step for placing the workpiece on the mold member is performed. FIG. 4 is a perspective view for explaining the workpiece placing step. In this workpiece placement step, first, the surface 11a of the workpiece 11 is made to face the placement surface 21a of the mold member 21 exposed upward, so that the recess 23 and the non-etched region correspond to each other.

  Next, in this state, the mounting surface 21 a of the mold member 21 and the surface 11 a of the workpiece 11 are brought into contact with each other. As described above, since the liquid level of the resist solution 25 is substantially flush with the mounting surface 21a of the mold member 21, the mounting surface 21a of the mold member 21 and the surface 11a of the workpiece 11 are brought into contact with each other. As a result, the resist solution 25 filling the recess 23 comes into contact with the non-etched region.

  After the workpiece placing step, a resist solution curing step is performed in which the resist solution 25 is cured to form an etching mask that covers the non-etched region. FIG. 5 is a perspective view for explaining the resist solution curing step. The resist solution curing step is performed by, for example, the baking apparatus 6 shown in FIG.

  A hot plate 8 on which the workpiece 11 and the mold member 21 are placed is disposed inside the bake device 6. In the resist solution curing step, first, the mold member 21 overlapped with the workpiece 11 is placed on the hot plate 8. Specifically, the back surface 21a of the mold member 21 is brought into contact with the upper surface of the hot plate 8, and the back surface 11b side of the workpiece 11 is positioned upward.

  Next, the mold member 21 is heated by raising the temperature of the hot plate 8. As a result, the resist solution 25 filling the recess 23 of the mold member 21 is cured while being in contact with the non-etched region of the workpiece 11, thereby forming an etching mask 27 (see FIG. 6). The heating temperature is set within a range where the resist solution 25 can be appropriately cured.

  After the resist solution curing step, a workpiece peeling step for peeling the workpiece 11 from the mold member 21 is performed. FIG. 6 is a perspective view for explaining the workpiece peeling step. In this workpiece peeling process, the workpiece 11 and the mold member 21 are separated at the interface (surface 11a and placement surface 21a). As a result, the etching mask 27 that covers the non-etching region remains on the surface 11 a of the workpiece 11.

  By using this etching mask 27 as a protective member at the time of etching, the etching region of the surface 11a can be appropriately processed to divide the workpiece 11 into a plurality of chips corresponding to each device 15. In the present embodiment, since the mounting surface 21a side of the mold member 21, particularly the inner surface of the recess 23, is coated with a material such as a fluororesin, the etching mask 27 remains on the mold member 21 side. Can be prevented.

  As described above, the etching mask forming method according to the present embodiment uses the plate-shaped mold member 21 in which the concave portion 23 corresponding to the non-etched region of the workpiece 11 is formed, and the concave portion 23 is formed into the etching solution 25. Then, the etching liquid 25 is cured by overlapping with the workpiece 11, so that the etching mask 27 can be formed by a simpler process than the conventional one without using an expensive photomask.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, the thermosetting resist solution 25 is heated in the resist solution curing step, but the resist solution curing step of the present invention is not limited to this. In the case of using a photocurable resist solution, the resist solution may be cured by irradiating light.

  In addition, the configurations, methods, and the like according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

11 Workpiece 11a Front surface 11b Back surface 13 Scheduled line (street)
15 Device 21 Mold member 21a Mounting surface (surface)
21b Back surface 23 Concave portion 25 Resist liquid 27 Etching mask 2 Supply device 4 Nozzle 6 Bake device 8 Hot plate

Claims (3)

A method of forming an etching mask that covers an unetched region of a workpiece having an etched region and a non-etched region partitioned by the etched region on a surface,
A plate-shaped mold member having a mounting surface of a size that covers the non-etching region of the workpiece, and having a recess having the same size as the non-etching region formed at a position corresponding to the non-etching region of the mounting surface A preparation process to prepare,
A resist solution supplying step of supplying a resist solution that is cured by an external stimulus to the recess of the mold member to fill the recess with the resist solution;
The resist in which the mounting surface of the mold member and the surface of the workpiece are opposed to each other, the workpiece is placed on the mold member in a state where the concave portion and the non-etched region correspond to each other, and the concave portion is filled A workpiece placing step for bringing the liquid into contact with the non-etched region;
A resist solution curing step in which an external stimulus is applied to the resist solution in a state where a workpiece is placed on the mold member to cure the resist solution, and an etching mask attached to the non-etched region is formed;
A method for forming an etching mask, comprising: a step of peeling off a workpiece having the etching mask formed on the surface thereof from the mold member after the resist solution curing step.   2. The method of forming an etching mask according to claim 1, wherein heat is applied as the external stimulus using the thermosetting resist solution.   3. The method of forming an etching mask according to claim 1, wherein an inner surface of the recess is coated with a material that prevents adhesion of the cured resist solution.