KR100726724B1 - Multi-layer mold structure for hot embossing - Google Patents

Abstract

A multi-layer molding apparatus for hot embossing is provided to achieve improved large area transferring performance of hot embossing by applying uniform pressure all over the molding apparatus. A multi-layer molding apparatus includes a molding layer(110), a cushion layer(120), and a rigidity retention layer(130). The molding layer is constituted by a wafer made of silicon. The wafer has one surface on which fine patterns(111) are formed. The cushion layer has one surface bonded to the other surface of the molding layer, and transforms in correspondence to the pressure generated when a material is pressed by the molding layer. The rigidity retention layer is bonded to the other surface of the cushion layer, and provides a flat reference surface which is not transformed even when the material is pressed by the molding layer.

Description

Multi-layer mold structure for hot embossing

1 is a cross-sectional view of a laminated mold apparatus according to a preferred embodiment of the present invention,

2 is a cross-sectional view showing a pressurized state of the PMMA sheet using the mold apparatus shown in FIG.

3A to 3C are photographs taken of the surface pressure paper experimented by Examples 1 and 2 and Comparative Examples of the present invention;

Figures 4a to 4c is a photograph of the hot-embossed material using the mold apparatus of Examples 1, 2 and Comparative Examples of the present invention,

5A to 5D are graphs showing channel widths and depths of hot-embossed materials by regions with respect to the X-axis and Y-axis directions using the mold apparatus of Embodiments 1 and 2 and Comparative Examples of the present invention;

6 is a plan view showing a pattern structure applied to the mold apparatus of the embodiment 1, 2 and comparative examples of the present invention.

<Description of the symbols for the main parts of the drawings>

100: mold apparatus 110: forming layer

111: Pattern 120: Cushion Layer

(130): rigid holding layer

The present invention relates to a mold apparatus used for molding a polymer material using a hot embossing process, and in particular, is composed of a laminated structure including a cushion layer to provide even pressing force over the entire area of the mold to improve large area transferability. The present invention relates to a laminated mold apparatus for hot embossing.

In general, a hot embossing process is a molding technique for transferring a fine pattern of a mold by pressing a polymer material heated above a glass transition temperature by using a mold apparatus having a fine pattern imprinted thereon. The hot embossing process can be used as a mass production technology for micro-optical parts, biochips, etc., because it can transfer several fine patterns or structures on a large-area material through a single press process.

In actual hot embossing, pattern transferability is sensitive to the process's turnaround time and to heating and cooling temperatures. In other words, in order to maintain the desired level of pattern transferability, the process required time is lengthened. On the contrary, if the process required time is reduced, the pattern transferability is reduced.

The pattern transferability may be classified into a single pattern transferability and a large area transferability. As described above, the pattern transferability depends on the temperature and the heating and cooling rate of the material, and even if the molding conditions confirm the transferability in a single pattern, sufficient transferability may not be obtained for the large area material. In this case, by increasing the molding temperature applicable to a single pattern or by lowering the heating / cooling rate, it is possible to improve the large area pattern transfer property, but this has a problem that leads to a decrease in mass productivity.

The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a laminated mold apparatus for hot embossing which can improve a large area pattern transferability.

Another object of the present invention is to provide a laminated mold apparatus for hot embossing to provide a uniform pressing force on the molding surface of a material.

In the mold apparatus used in the hot embossing process, the present invention to achieve the object as described above and to perform the problem for removing the conventional defects,
A shaping layer comprising a fine pattern processed on one surface of a wafer made of silicon (Si);
A cushion layer having a structure in which one surface thereof is coupled to the other surface of the molding layer to face each other, and having a stacked structure, the cushion layer being deformed in response to the pressure generated when the workpiece is pressed by the molding layer; And
Stacked mold apparatus for hot embossing comprising: a rigid holding layer that is coupled to the other surface of the cushion layer so as to face each other and has a laminated structure, and provides a flat reference surface without deformation even when pressing the processing material by the molding layer. It is characterized by.

delete

delete

delete

Hereinafter, described in detail with reference to the accompanying drawings as follows.

1 shows a cross-sectional structure of a mold apparatus of the present invention. Referring to FIG. 1, the mold apparatus 100 of the present invention has a structure in which a molding layer 110, a cushion layer 120, and a rigid maintenance layer 130 are sequentially stacked. The mold apparatus 100 has a pressure distribution on the large area by the molding layer 110 to be evenly formed by causing the cushion layer 120 to deform in response to the pressure transmitted from the molding layer 110 when the workpiece is pressed. I would have to.

The shaping layer 110 has a fine pattern 111 for forming a processed material is processed on one surface, and is made of silicon (Si).

The cushion layer 120 is coupled to the upper portion of the forming layer 110 so that its bottom face is opposite to the other surface of the forming layer 110, the soft cushioning action so that it can be deformed in response to the pressure transmitted when the workpiece is pressed. Consisting of polydimethylsiloxane (PDMS).

The rigid maintenance layer 130 is coupled to the upper portion of the cushion layer 120 to face the bottom of the cushion layer 120, and is configured to provide a flat reference plane without deformation even when pressing the workpiece.

The molding layer 110, the cushioning layer 120, and the rigid holding layer 130 as described above may be formed by being bonded to each other by anodic bonding, or to prevent air from being trapped between the layers. It can also be configured by simply stacking each layer. This is because the hot embossing process can be performed without problems due to the characteristics of the processing equipment unless it is artificially removed. Preferably, in consideration of the characteristics of the various processing equipment to use a method of mutual bonding using annodic bonding as described above.

FIG. 2 is a cross-sectional view showing a state when the PMMA sheet is pressed by using a laminating mold apparatus. Referring to FIG. 2, when pressing the PMMA sheet 200 having a flatness problem on a large area in the hot embossing process with the stacked mold apparatus 100, the surface of the PMMA sheet 200 due to the role of the cushion layer 120. The pattern can be transferred evenly along.

Hereinafter, the operation of the present invention will be described as follows.

Example 1

In this embodiment, a surface pressure paper having a pressure range of 0.6 to 10 MPa is placed on a 4-inch polymethylmethacrylate (PMMA) sheet having a thickness of 0.5 mm, and the laminated mold apparatus is placed thereon. The experiment was performed in. At this time, 6-inch glass wafer (glass wafer) was used as the mold holding device, 4-inch silicon wafer (Si wafer) was used as the molding layer, and the PDMS pad having a thickness of 1.3 mm was used as the cushion layer. Was used. In addition, the present embodiment is only to see the distribution of the pressing force at room temperature, the silicon wafer is not processed fine pattern, and the heating and cooling process is omitted. The process time was 20 seconds and the actual press time was 6 seconds. At this time, the pressing force was set to 10 kN.

Example 2

In this embodiment, a PDMS pad having a thickness of 2.4 mm was used as a cushion layer, and the rest of the conditions were the same as in Example 1.

Comparative example

This embodiment uses a conventional mold apparatus that is not provided with a cushion layer, and was performed under the same conditions as in Example 1 except for the cushion layer.

3A to 3C are photographed the surface pressure paper experimented through Examples 1 and 2 and Comparative Examples. In the case of Example 1, it can be seen that the pressure difference by area of the surface pressure paper as shown in Figure 3a, which is caused by poor flatness of the PDMS pad and air bubbles trapped between the PDMS pad and the silicon wafer. It is shown. In the case of Example 2 it can be seen that the pressure is uniformly applied over the entire area of the surface of the pressure paper as shown in Figure 3b, which is caused by the increase in the thickness of the cushion layer (badness of flatness of the PDMS pad, Air bubbles).

However, in the case of the comparative example using the mold apparatus is not provided with a cushion layer can be seen that the pressure acts only on the edge portion of the surface pressure paper as shown in Figure 3c.

Next, the square pattern was repeatedly processed in various parts on the silicon wafer in the molding layer of the mold apparatus used in Examples 1, 2 and Comparative Example to perform the actual hot embossing process under the same conditions.

On the other hand, the glass transition temperature (Tg) of PMMA is known as 106 ℃, the heating temperature was set to 110 ℃ slightly higher than this. In this experiment, the hot embossing process was performed over a sufficiently long time of about 2 hours to exclude the effect of thermal deformation. The heating time was 15 minutes, the pressurization time was 10 minutes, the cooling time was 1 hour 25 minutes, and the pressing force was 12 bar.

4A to 4C are images of PMMA sheets on which fine patterns have been transferred by hot embossing processes using respective mold apparatuses. FIG. 4A uses the mold apparatus of Example 1, FIG. 4B uses the mold apparatus of Example 2, and FIG. 4C uses the mold apparatus of Comparative Example. As can be seen in the picture of Figures 4a to 4c it can be seen that the pattern is most evenly transferred to the PMMA sheet of Figure 4b using a mold apparatus equipped with a PDMS pad of 2.4mm thickness.

5A to 5D illustrate the width and depth of the pattern transferred to the PMMA sheet with reference to the X-axis and Y-axis directions of the PMMA sheet. At this time, the pattern processed in the molding layer of the mold apparatus has a structure as shown in Figure 6, the shape of the actual pattern is provided in each rectangular area, it is not shown in the drawings. As can be seen in Figures 5a to 5d it can be seen that the thicker the PDMS pad, that is, the cushion layer is provided, the better the molding results.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

The present invention provides a mold apparatus having a structure in which a molding layer having a relatively high rigidity, a cushion layer having elasticity, and a rigid holding layer having high rigidity are sequentially stacked as described above, thereby providing a large area transferability of a hot embossing process. It can be improved. Accordingly, the yield of the hot embossing process can be significantly improved.

Claims (3)

delete In the mold apparatus used in the hot embossing process, A shaping layer comprising a fine pattern processed on one surface of a wafer made of silicon (Si); A cushion layer having a structure in which one surface thereof is coupled to the other surface of the molding layer to face each other, and having a stacked structure, the cushion layer being deformed in response to the pressure generated when the workpiece is pressed by the molding layer; And Hot embossing, comprising: a rigid retaining layer having a structure in which one surface thereof is coupled to the other surface of the cushion layer to face each other, and a flat reference surface without deformation even when the workpiece is pressed by the forming layer. Stacking Mold Apparatus The method of claim 2, wherein the cushion layer, Laminated mold apparatus for hot embossing, characterized in that made of polydimethylsiloxane (PDMS).

Images