JP2000194142A - Pattern forming method and production of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming method using an imprint method by which the compression pressure between the mold and a substrate can be reduced without accompanying changes in the substrate temperature, and to provide a producing method of a semiconductor device. SOLUTION: This method includes a step to form a photocuring material layer 22 comprising a liquid photocuring material on a substrate 12, a step to press a mold 10 comprising a translucent material and having grooves of a predetermined pattern to one surface side to the substrate 12, and a step to irradiate the other face side of the mold 10 to cure the photocuring material layer 22 and to form a resist pattern having a pattern fitted to the pattern of the grooves 14, and a step to detach the mold 10 from the substrate 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pattern forming method using an imprint method and a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Hitherto, a method of optically transferring a pattern has been used to form a pattern requiring fine processing such as a semiconductor device manufacturing process. For example, an optical mask in which an opaque pattern is drawn on a part of a transparent substrate is created, and this is placed directly or indirectly on a resist-coated semiconductor substrate, and light is irradiated from the back of the optical mask. By selectively exposing the resist in the light transmitting portion to the light, the pattern of the optical mask is transferred to the resist on the semiconductor substrate. In the current semiconductor device manufacturing process, a method of transferring a pattern onto a semiconductor substrate by optically reducing a mask pattern has become mainstream.

However, in these pattern forming methods, the size of the pattern to be formed is greatly limited by the wavelength of the light to be exposed, and in the case of reduced projection exposure, the pattern is not only aligned in the horizontal direction but also in the vertical direction of the substrate. Since precision is required, there is a disadvantage that the cost of the apparatus is increased. Against this background, SYChou et al. Propose a technique called imprinting, which is very simple but suitable for mass production and can transfer a much finer pattern than conventional methods (for example, Appl. .Phys.Lett., Vol.67, p.331
4 (1995)).

A conventional imprint method proposed by SYChou et al. Will be described with reference to FIG. First, a silicon substrate 102 having a silicon oxide film 104 formed on its surface
Is prepared, and the silicon oxide film 10 on the silicon substrate 102 is prepared.
4 is processed to an inverted pattern corresponding to a mirror image of the pattern to be transferred, in actual size. For patterning the silicon oxide film 104, for example, a normal electron beam lithography technique can be used. Thus, the mold 1 having irregularities corresponding to the mirror image of the pattern to be transferred on the surface thereof
00 (FIG. 3A).

Next, a resist material such as PMMA is applied and cured on the silicon substrate 110 on which a pattern is to be formed. Thus, a resist layer 112 is formed on the silicon substrate 110 (FIG. 3B). Then
The silicon substrate 110 on which the resist layer 112 is formed
Heat to about 00 ° C. to slightly soften the resist layer 112.

Next, the mold 100 and the silicon substrate 110 are overlapped with each other such that the uneven surface side of the mold 100 faces the application surface side of the resist layer 112 of the silicon substrate 110, and pressure-bonded at a pressure of about 140 atm (FIG. 3).
(C)). Next, the mold 100 is moved to the silicon substrate 11.
The temperature is lowered to about 105 ° C. in a state where the mold is pressed to 0, the resist layer 112 is cured, and the mold 100 is detached. Thereby, the resist layer 1 on the silicon substrate 110 is formed.
12, a resist pattern 114 having a mirror image pattern corresponding to the concavo-convex pattern of the mold 100, that is, a pattern to be formed on the silicon substrate is formed (FIG. 3D).

Thus, a resist pattern has been formed using the imprint method.

[0008]

However, the pattern forming method using the conventional imprint method has the following problems to be solved. That is, as described above, the pattern forming method using the imprinting method requires an extremely high pressure of about 140 atm when the mold and the substrate are pressed. It was extremely difficult to maintain the horizontal positional accuracy between the two.

In addition, in the above-described pattern forming method, it is indispensable to raise and lower the substrate temperature, so that an increase in the processing time due to the change in the substrate temperature is inevitable. SUMMARY OF THE INVENTION An object of the present invention is to provide a pattern forming method using an imprint method, which can reduce the pressure required for pressing a mold and a substrate, and which does not involve a change in the substrate temperature, and a method for forming such a pattern. An object of the present invention is to provide a method for manufacturing a semiconductor device using the same.

[0010]

The object of the present invention is to form a photo-curable material layer made of a liquid photo-curable material on a base substrate, and to form a photo-curable material layer on one side of the photo-curable material. A mold in which a groove of a predetermined pattern is formed, such that the one surface side faces the surface side of the base substrate on which the photocurable material layer is formed, and pressure-bonds the base substrate. Curing the photocurable material layer by irradiating light from the other side of the mold, forming a resist pattern having a pattern made of the photocurable material and fitted to the predetermined pattern; and And detaching the mold from the base substrate.

In the above-described pattern forming method,
After the step of curing the photocurable material layer or the step of detaching the mold, a step of performing a heat treatment on the base substrate may be further provided. Further, the object is to form a photocurable material layer made of a liquid photocurable material on a base substrate, and to form a groove having a predetermined pattern on one surface side, which is made of a light transmissive material. Pressing the formed mold against the base substrate such that the one surface side faces the surface of the base substrate on which the photocurable material layer is formed, and the other surface side of the mold. Curing the photo-curable material layer by irradiating light from the substrate, forming a resist pattern having a pattern that is made of the photo-curable material and that fits into the predetermined pattern; and And a step of etching the base substrate using the resist pattern as a mask.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pattern forming method and a method for manufacturing a semiconductor device according to one embodiment of the present invention will be described with reference to FIGS. 1 and 2 are process sectional views showing the pattern forming method and the semiconductor device manufacturing method according to the present embodiment. First, a substrate 12 made of a light-transmitting material is prepared as a base material of the mold (FIG. 1).
(A)). For example, a substrate such as a quartz substrate or a Pyrex substrate has optical transparency to light up to the ultraviolet region and is excellent in applicability to a semiconductor device manufacturing process. It is suitable for application to a device manufacturing method. However, the substrate material is not limited to quartz or Pyrex, and other substrates having optical transparency can be similarly applied.

Next, the surface of the substrate 12 is processed to an inverted pattern corresponding to a mirror image of the pattern to be transferred, in actual size. This processing is to form the grooves 14 corresponding to the pattern on the surface of the substrate 12, and for example, a technique such as ordinary electron beam lithography can be used. Thus, a mold 10 having irregularities corresponding to the mirror image of the pattern to be transferred on its surface is formed.
(B)). The term “mold” generally means a mold or a stamp, and the mold in this specification corresponds to a stamp for forming a predetermined resist pattern on a substrate on which a pattern is to be formed.

Next, a photocurable substance which is liquid at room temperature is applied to the surface of the substrate 20 on which a pattern is to be formed. Thus, a photocurable substance layer 22 made of a photocurable substance is formed on the substrate 20 (FIG. 1C).
The photocurable substance that is liquid at room temperature is selected from substances that are cured by irradiation with light having a wavelength that can transmit through the mold 10. For example, a photocurable resin such as a photopolymer or a negative resist can be used.
The photocurable substance is used in consideration of properties such as resistance as a resist (for example, etching resistance), adhesion to the substrate 20, and ease of peeling from the mold 10, and the purpose of use, the material of the mold 10 and the substrate 20, and the like. It is desirable to select as appropriate according to.

The substrate 20 may be a bare semiconductor substrate on which no elements are formed, or may be a semiconductor substrate on which predetermined elements are already formed. Further, a substrate other than a semiconductor substrate may be used. In this specification, these substrates are collectively referred to as a base substrate. Next, the mold 10 and the substrate 20 are overlapped with each other so that the uneven surface side of the mold 10 faces the surface of the substrate 20 on which the photocurable material layer 22 is formed (FIG. 1D). Crimp. Accordingly, the liquid photo-curable substance layer 22 flows according to the concavo-convex pattern formed on the surface of the mold 10, and as a result, the photo-curable substance layer 22 fits into the concavo-convex pattern formed on the surface of the mold 10. The concavo-convex pattern, that is, the pattern to be transferred onto the substrate 20 is maintained (FIG. 2A).

Since the photocurable substance layer 22 is in a liquid state, the pressure required for pressure bonding between the mold 10 and the substrate 20 is about several atmospheres. Further, even after the mold 10 is brought into contact with the photocurable substance layer 22, the mold 10 can be relatively easily moved in the horizontal direction. Therefore, the positioning of the mold 10 with respect to the substrate 20 becomes easy.

Next, with the mold 10 and the substrate 20 pressed together, light (for example, ultraviolet rays) is irradiated from the back side of the mold 10 to cure the photocurable material layer 22 (FIG. 2).
(B)). As a result, the photocurable substance layer 22 is cured in a state where it has a concave / convex pattern that fits into the concave / convex pattern formed on the surface of the mold 10, that is, a pattern to be transferred onto the substrate 20 (hereinafter, cured). The photocurable substance layer 22 is represented as a photocurable substance layer 24). In addition,
Irradiation light is sufficient to cure the photo-curable material layer 22 with this light, so it is not necessary to apply light having a wavelength uniformity or a point light source as used in ordinary photolithography, Normal lamp light can be used.

Next, the mold 10 is detached from the substrate 20. At this time, since the photocurable substance layer 24 has been cured, the photocurable substance layer 24 is maintained in a state where the mold 10 was pressed (FIG. 2C). Note that, depending on the photocurable substance, it is conceivable that the photocurable substance layer 24 cannot be sufficiently cured only by light irradiation. In such a case, the photocurable material layer 24 may be sufficiently cured by performing a predetermined heat treatment in a state where the mold 10 is pressed or immediately after the mold 10 is detached.

Next, if necessary, the photo-curable material layer 24 on the entire surface of the substrate 20 is slightly etched, and the photo-curable material layer 24 that thinly remains in the region where the photo-curable material layer 24 should not remain. Is removed. Thereby, the resist pattern 2 composed of the photocurable substance layer 24 is formed on the substrate 20.
6 is formed (FIG. 2D).

Next, predetermined processing is performed on the substrate 20 using the resist pattern 26 formed as described above as a mask. For example, the substrate 20 is etched using the resist pattern 26 as a mask,
Can be applied to the substrate 20 using the mask as a mask. As described above, according to the present embodiment, since the liquid photocurable substance is used in the pattern forming method using the imprint method, the pressure for pressing the mold and the substrate is reduced as compared with the conventional pattern forming method. It can be significantly reduced. In addition, since a light-transmitting substrate is used as a material forming the mold, a photocurable substance can be used as a material for forming a pattern. This eliminates the need to change the substrate temperature due to the pattern formation, thereby shortening the processing time.

[0021]

As described above, according to the present invention, a step of forming a photocurable substance layer made of a liquid photocurable substance on a base substrate, A step in which a mold in which a groove of a predetermined pattern is formed on the surface side is pressure-bonded to the underlying substrate such that one surface side faces the surface of the underlying substrate on which the photocurable material layer is formed, and Curing the photocurable material layer by irradiating light from the other surface side, forming a resist pattern made of a photocurable material and having a pattern fitted to a predetermined pattern; and Since the resist pattern is formed by the step of desorption, the pressure for pressing the mold and the substrate can be significantly reduced as compared with the conventional pattern forming method. In addition, since a light-transmitting substrate is used as a material forming the mold, a photocurable substance can be used as a material for forming a pattern. This eliminates the need to change the substrate temperature due to the pattern formation, thereby shortening the processing time.

Therefore, by applying the pattern forming method according to the present invention, the investment in the manufacturing apparatus can be reduced and the manufacturing process can be simplified.

[Brief description of the drawings]

FIG. 1 is a process cross-sectional view (part 1) illustrating a pattern forming method and a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a process cross-sectional view (part 2) illustrating the pattern forming method and the semiconductor device manufacturing method according to one embodiment of the present invention;

FIG. 3 is a process sectional view showing a conventional pattern forming method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Mold 12 ... Substrate 14 ... Groove 20 ... Substrate 22 ... Photocurable material layer (before hardening) 24 ... Photocurable material layer (after hardening) 26 ... Resist pattern 100 ... Mold 102 ... Silicon substrate 104 ... Silicon oxide film 110: silicon substrate 112: resist layer 114: resist pattern

Claims (3)

[Claims] 1. A step of forming a photocurable substance layer made of a liquid photocurable substance on an undersubstrate, and forming a groove of a predetermined pattern on one surface side of a light transmissive substance. The molded mold, the one surface side is opposed to the surface side of the underlying substrate on which the photocurable material layer is formed, and pressure-bonded to the underlying substrate, from the other surface side of the mold Curing the photo-curable material layer by irradiating light, a step of forming a resist pattern made of the photo-curable material and having a pattern fitted to the predetermined pattern, and forming the mold from the base substrate. A pattern forming method. 2. The pattern forming method according to claim 1, further comprising a step of performing a heat treatment on the base substrate after the step of curing the photocurable material layer or after the step of detaching the mold. A pattern forming method, characterized in that: 3. A step of forming a photocurable substance layer made of a liquid photocurable substance on an undersubstrate; forming a groove of a predetermined pattern on one surface side of a light transmissive substance. The molded mold, the one surface side is opposed to the surface side of the underlying substrate on which the photocurable material layer is formed, and pressure-bonded to the underlying substrate, from the other surface side of the mold Curing the photo-curable material layer by irradiating light, a step of forming a resist pattern made of the photo-curable material and having a pattern fitted to the predetermined pattern, and forming the mold from the base substrate. A method for manufacturing a semiconductor device, comprising: a step of desorbing; and a step of etching the base substrate using the resist pattern as a mask.