KR20080085510A - Rapid thermal pressing (rtp) apparatus for nanoimprint lithography - Google Patents

Abstract

A nanoimprint lithography apparatus for a rapid thermal pressing and a heating method are provided to reduce the heating and cooling time and to improve the productivity by rapidly heating a surface of a metal stamp using a skin effect. A lower base(61) is prepared on an inner lower side of a nanoimprint lithography apparatus and a metal support plate is placed on an upper part of the lower base. An upper base(62) is prepared on an inner upper side of the nanoimprint lithography apparatus and a metal stamp is placed on a lower part of the upper base. A plurality inserting grooves are formed at a lower part of the upper case. An upper base vertical movement unit moves the upper base upwardly and downwardly on the basis of the lower base and includes a slide guide bar(63) functioning as a guide with respect to the movement of the upper base. A rectangular helical coil is fixed on the lower base and installed in an inserting groove formed on the upper base. The metal stamp is installed between upper and lower support plates and has a desired pattern of a nano or micro scale. A polymer resist(20) is interposed between the metal stamp and a supporting plate material.

Description

Microimprint lithography apparatus and heating method capable of rapid molding {RAPID THERMAL PRESSING (RTP) APPARATUS FOR NANOIMPRINT LITHOGRAPHY}

1 is a process flow chart of fine imprinting,

2 is a perspective view showing the shape of a flat plate heating coil of a fine imprint lithography apparatus capable of rapid molding according to the present invention;

3 is a plan view and a side view showing the shape of a flat plate heating coil of a microimprint lithography apparatus capable of rapid molding according to the present invention;

Figure 4 is a graph showing the temperature history for each measurement position of the metal stamp during induction heating of the present invention rapid forming fine imprint lithography apparatus;

5 is a perspective view showing a microimprint lithography apparatus capable of rapid molding according to the present invention;

6 is a cross-sectional view showing a microimprint lithographic apparatus of the present invention capable of rapid molding;

Figure 7 is a cross-sectional view showing the plate material for each use in the coil of the present invention rapid forming fine imprint lithography apparatus;

8 is a plan view showing a measurement position for verifying the temperature distribution of the present invention, the rapid molding fine imprint lithography apparatus;

9 is a photograph showing a microimprint lithography apparatus capable of rapid molding with uniformly spaced induction heating coils,

FIG. 10 is a graph of temperature distribution by measurement position of FIG. 8 using the apparatus of FIG.

11 is a photograph showing a microimprint lithography apparatus capable of rapid molding with induction heating coils of non-uniform spacing;

FIG. 12 is a graph of temperature distribution by measurement position of FIG. 8 using the apparatus of FIG.

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

(10): metal stamp (20): polymer resist

(30): support plate 40: coil

61: lower base 62: upper base

(63): slide guide bar 64: lower support plate

65: upper support plate 70: metal support plate

The present invention relates to an imprint lithography apparatus and a heating method capable of rapid molding, and more particularly, a metal mold for nanoimprint lithography is rapidly heated using high frequency induction heating, and a high frequency induction coil is formed in a rectangular spring shape. It can be formed to cover a uniform temperature distribution, and the rapidly heated metal mold instantly heats only the surface of the polymer resist above the glass transition temperature (Tg) to form a fine pattern already stamped on the metal mold. The present invention relates to a microimprint lithography apparatus and a heating method capable of rapid molding, which are pressurized and transferred to a polymer resist.

Nanoimprint Lithography (NIL) is a technology for forming fine patterns by making nano-level molds and forming nano patterns by applying pressure on polymer resists to transfer patterns as if they are painted. As a technology that has been attracting attention as a next generation pattern forming technology because of its simple and low cost, the technology is described in Korean Patent Application No. 10-2004-0003394.

Such a nanoimprint lithography process includes a step of mounting a mold and a work material into a vacuum chamber of a molding apparatus as shown in FIG. 1, an alignment step of vacuuming a vacuum chamber, and a stamp having a desired pattern of nano or micro scale. (Stamp, mold) and the heating step of heating the plastic plate and above a certain temperature, by pressing the stamp (stamp, mold) and the plastic plate under high pressure (10 ~ 30 bar) under high temperature condition (about 120 ℃) It is divided into a transfer step of transferring the pattern of the stamp to the plastic plate, a cooling step of cooling the plastic plate below a predetermined temperature after the transfer step is completed, and a release step of opening the vacuum chamber and taking out the processed material. The total process time is 30 to 40 minutes and takes a long cycle time.

The conventional heating method used in the most time-consuming heating and cooling step of each of these steps is to place the heating plate around the stamp and heat the heating plate first using an electric heating wire, and then the stamp conducts heat from the heating plate. Indirect heating method is adopted to heat the stamp. However, this indirect heating method has a low heating efficiency, other parts in addition to the heating portion is heated together with the problem of cooling time is also a major cause of productivity degradation.

The present invention has been made to solve the above problems, and in particular, to provide a fine imprint lithography apparatus and a heating method capable of rapid molding to achieve a technical problem of reducing the cycle time of the nanoimprint lithography process, in particular By using the skin effect, only the surface of the metal stamp is rapidly heated, and only the surface of the polymer resist is formed by instantaneously conducting heat above the glass transition temperature (Tg) to form not only the heating time but also the cost of cooling time. It aims to improve productivity by reducing productivity by reducing the temperature distribution of metal mold.

SUMMARY OF THE INVENTION An object of the present invention, which achieves the above object and accomplishes a problem for eliminating the conventional drawback, is an imprint lithography apparatus capable of rapidly forming a fine pattern on the surface of a polymer resist, wherein an enclosed space is formed therein. Chamber available; Pressure regulating means capable of adjusting a pressure (vacuum) in the chamber; A lower base provided below the chamber and having a processing object positioned thereon; An upper base provided above the chamber and positioned at a lower portion thereof; An upper base vertical movement means including a slide guide bar which moves up and down and guides the upper base based on the lower base; One side is fixed to the lower base and the pressing means is installed to allow relative movement with the upper base; A metal stamp having a desired pattern of nano or micro scale installed between an upper support plate and a lower support plate circulating therein, the same size as the metal stamp positioned below the polymer resist and the polymer resist to which the pattern of the metal stamp is transferred, and A metal support plate made of a material; It is achieved by providing an imprint lithographic apparatus comprising a transfer means for supplying said polymer resist between a metal stamp and a metal support plate material.

Meanwhile, in the present invention, by using a coil having a shape such as a square spring, which is a high frequency induction heating means, the magnetic field flows in the same direction at the center thereof so that the temperature of the metal stamp can be uniformly heated. It is formed to form a cooling water flow into the coil to suppress the temperature rise of the coil itself, and at the same time to cool the lower base and the lower base is always heated in the heating process to reduce the cooling time to increase the productivity.

Here, induction heating is used for metal heating, and precisely called high frequency induction heating. When alternating magnetic flux is generated by alternating currents around the coil, the alternating magnetic flux is generated. Inductive currents are generated in the conductor placed on the magnetic field. This current is called the eddy current (electrical force that prevents the change of the magnetic lines generated in the conductor), and the resistivity of the heating object (metal or conductor) and Joule heat due to the eddy current are generated, which is called eddy current loss. And it becomes a heating source (발열 原) during induction heating, and if the frequency is increased, only the surface of the object to be heated can be concentrated by the skin effect.

On the other hand, induced current is generated only in the conductor placed in the magnetic field during induction heating. Therefore, the induction heating can be limited to electric conductors, and it is preferable to select materials from non-conductors such as ceramics, glass, and engineering plastics other than the heated object. The higher the magneticity among the conductors, the better the heating efficiency. It should be excellent in heat resistance and strength.

In addition, the lower base serves to provide a function and a work space for fixing the coil, and the material is preferably a non-conductive or diamagnetic material through which current cannot flow.

The upper base moves only in the vertical direction by the slide guide bar and serves to pressurize the metal stamp. A plurality of grooves having a lower opening are formed to insert and move the upper portion of the coil. It is preferable to use a conductor, a diamagnetic material, and the movement of the upper base is realized using conventionally known techniques such as the movement of the upper die of the press.

In addition, the slide guide bar is based on the lower base, the upper base is moved up and down to guide it, it is preferable to use a non-conductive, diamagnetic material that can not flow current.

The upper and lower support plates, through which the coolant is circulated, are used to uniformly press the metal stamp and the polymer resist, and the support plate cools the metal stamp and the metal support plate. The material is a non-conductor that cannot flow current and has a relatively good thermal conductivity. It is preferable to use diamagnetic material.

The metal stamp has a desired pattern of nano or micro scale, and the material is preferably made of a material having good magnetic properties, electrical conductors, and thermal conductors such as nickel.

The metal support plate is preferably made of a material such as a metal stamp, a metal plate of the same size, but is heated to the same temperature as the metal stamp to prevent bending of the polymer resist as only one side is heated.

The polymer resist supply means uses a conventionally known technique such as a robot or a supply conveyor for supplying a wafer into the chamber.

Hereinafter, the configuration and the operation of the embodiments will be described in detail with reference to the accompanying drawings.

2 is a perspective view showing the shape of a flat plate heating coil of the present invention rapidly forming fine imprint lithography apparatus, FIG. 3 is a plan view and a side view showing the shape of the plate heating coil of the present invention rapidly forming fine imprint lithography apparatus, FIG. 5 is a graph showing a temperature history of each metal stamp at a measurement position during induction heating of a microimprint lithography apparatus capable of rapid molding, FIG. 5 is a perspective view of a microimprint lithography apparatus capable of rapid molding according to the present invention, and FIG. A cross-sectional view showing a possible fine imprint lithography apparatus, and FIG. 7 is a cross-sectional view showing plate materials for respective applications in the coil of the present invention, which can be rapidly formed.

As shown in the drawing, in the rapid heating of the metal stamp for fine imprinting, induction heating means having a coil 40 which is spirally configured for induction heating, and fixing the coil to provide a working space A lower base 61 for giving, a slide guide bar 63 capable of moving the upper base in a vertical direction based on the lower base, and a groove in which the coil can be inserted and movable in the vertical direction A lower support plate 64 provided with an upper base 62 and a metal support plate xx installed on the lower base to prevent molding of the polymer resist and preventing bending of the polymer resist and heated by the coil 40, and a metal stamp. It is composed of an upper support plate (65) having a metal stamp (10) which is used to uniformly press and is heated by the coil (40). In addition, the upper support plate 65 and the lower support plate 64 in which the coolant is circulated therein in the cooling step after the pressurization step cool the heated metal stamp 10 and the metal support plate 70.

The induction heating means is provided with a coil 40 formed in a spiral of a rectangular spring shape that rotates as if it surrounds the metal stamp 10, each winding of the coil 40 is fixed through the lower base 61 have.

FIG. 8 is a plan view showing a measurement position for verifying a temperature distribution of a metal stamp inside a coil of an imprint lithography apparatus of the present invention, and FIG. 9 is a fine imprint capable of rapid forming having induction heating coils having a uniform interval. A photograph showing a lithographic apparatus.

As shown in FIG. 8, in order to grasp the vertical temperature distribution and the horizontal temperature distribution of the coil, a temperature sensor was installed on the metal stamp, which is the object to be heated, and the temperature was measured. The graph of the temperature distribution is shown in FIG. 10.

Looking at Figure 10 it can be seen that the temperature deviation in the vertical direction and the horizontal direction slightly appears in the outer portion of the mold in the overall temperature distribution.

Another embodiment for improving this is shown in FIG. 11, and a temperature distribution measurement graph for the same embodiment as shown in FIG. 11 is shown in FIG. 12.

As shown in FIG. 11, the coils for induction heating were arranged, but the windings of the coils at both ends of the coils were narrowed. Referring to the graph measuring the temperature distribution according to this in Figure 12, unlike the temperature distribution shown in Figure 10 it can be seen that the temperature deviation is significantly reduced.

That is, the temperature deviation can be reduced by narrowing the winding interval in the direction where the temperature deviation is high.

The slide guide bar 63 is provided at each corner of the upper base and is movable up and down vertically.

The upper base 62 is capable of moving up and down, and forms a plurality of grooves so that each winding of the coil can be inserted so as to move past the coil so that the upper support plate 65 is not affected by the coil 40. To be pressurized.

The lower support plate 64 is installed at the upper end of the central portion of the lower base 61, the upper support plate 65 is heated by the coil 40 to the metal stamp 10 to form a polymer resist (20) Is installed and the heated metal stamp 10 is instantaneously conducts heat to the surface of the polymer resist 20 and then pressurized to enable molding. The upper and lower support plates 65 are coupled with guide pins (not shown) so that the metal stamp, the polymer resist, and the metal support plate are in place. The upper and lower support plates uniformly press the pressure of the metal stamp and the metal support plate during molding. In the cooling step, the coolant is circulated inside to take heat from the metal stamp and the metal support plate.

In addition, each color of the graph in FIG. 4 shows the temperature of each measuring position of a metal mold, and it turns out that a temperature distribution is uniform throughout.

Hereinafter, a method of transferring a pattern onto a surface of a polymer resist using a microimprint lithography apparatus capable of rapid molding will be described below.

First raising the upper base to form a space between the upper base and the lower base, placing a polymer resist on which the pattern is to be recorded between the metal stamp and the support plate material by the substrate supply means, and operating the pressure regulating means of the chamber. Adjusting the pressure (vacuum), rapidly heating the metal stamp and the metal support plate by flowing a high frequency in the square spring spiral coil, and heating the surface of the polymer resist by the heated metal stamp and the metal support plate. By pressing the metal stamp and the metal support plate in the state, the pattern recorded on the metal stamp is transferred to the polymer resist. After heating and pressing, the electric current of the coil is cut off and the cooling water flows to the upper and lower support plates to cool the metal stamp and the metal support plate. Cooling the polymer resist, upon raising the upper base Opens the step, the metal stamp and the support plate consists of a step of extracting the molded article.

Such a process has been described in that the metal stamp and the metal support plate are fixed to the upper and lower support plates to supply the polymer resist, but the metal stamp and the polymer resist and the metal support plate may be supplied together.

That is, the upper base may be raised and the upper support plate may be raised to place a metal support plate, a polymer resist, and a metal stamp between the upper support plate and the lower support plate.

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

The effects of the present invention that can be expected by the configuration and action as described above are as follows.

High frequency induction heating allows the metal stamp to be heated rapidly, allowing local heating compared to the conventional heating method, saving energy, and using the skin effect generated at high frequency. Rapid heating only the surface reduces the time and cost of heating and cooling to improve productivity, and rapidly heated metal molds only heat the surface of the polymer resist instantaneously above the glass transition temperature (Tg) to make fine By pressing and molding the pattern on the polymer resist, it saves the heating and cooling time.The polymer resist can be heated with the metal stamp and the metal support plate to prevent warpage of the plastic plate and the metal stamp using the spiral coil. The temperature uniformity by forming a metal support plate It is possible to increase the degree, which is advantageous for large area, and has the technical effect of enabling mass production through mass production process.It also suppresses the temperature rise of the coil itself by flowing coolant into the coil, and cooling channels are provided inside the upper and lower support plates. Is formed to pass through the cooling water to directly cool the metal stamp and the metal support plate of the elevated temperature during the heating process to increase the productivity by reducing the cooling time of the molded polymer resist.

Claims (6)

An imprint lithography apparatus capable of rapidly forming a fine pattern on a surface of a polymer resist, A lower base provided inside the apparatus and having a metal support plate positioned thereon; An upper base provided above the inside of the apparatus, the metal stamp being positioned at the bottom thereof, and having a plurality of insertion grooves formed at the bottom thereof; An upper base vertical movement means including a slide guide bar that moves the upper base up and down based on the lower base and guides the upper base; A spring-shaped square spiral coil fixed to one side of the lower base and installed so that each winding of the coil can be inserted into an insertion groove formed in the upper base, and rotating like a metal stamp; Supplying a metal stamp having a desired pattern of nano or micro-scale installed between the upper support plate and the lower support plate, a metal support plate of the same material as the metal stamp, a polymer resist placed between the metal stamp and the support plate material, the polymer resist Microimprint lithography apparatus capable of rapid molding, characterized in that it comprises a material supply means. The method of claim 1, Rapid narrowing imprint lithography apparatus, characterized in that for reducing the temperature deviation by narrowing the winding distance between both ends of the spiral coil than the central portion. The method of claim 1, Cooling water flows into the coil to suppress the temperature rise of the coil itself, characterized in that the rapid molding fine imprint lithography apparatus. The method of claim 1, Between the upper base and the lower base, the upper and lower support plates and the lower support plate which equalize the pressure of the metal stamp and the metal support plate during molding and have a cooling channel formed therein to cool the heated metal stamp and the metal support plate through the cooling water are further formed. Microimprint lithography apparatus capable of rapid molding, characterized in that it is included. The method of claim 1, And the lower base, the upper base, the slide guide bar, the upper support plate, and the lower support plate use a material as a non-conductor. An imprint lithography method capable of rapidly forming a fine pattern on a polymer resist, comprising: raising a top base to form a space between the top base and a bottom base, and supplying the polymer resist to be recorded with the metal stamp and the metal by the supply means. Placing between the support plates, operating the pressure regulating means to adjust the pressure inside the chamber to evacuate, rapidly heating the metal stamp and the metal support plate material by flowing a high frequency in the spring-shaped spiral coil, and heating the metal stamp. And pressurizing the metal stamp while the surface of the polymer resist is instantaneously heated by the metal support plate to transfer the fine pattern imprinted on the metal stamp to the polymer resist, cutting off the current in the coil after heating and pressing the upper and lower support plates. Cooling water flowing through metal stamp and metal Cooling the support plate to cool the polymer resist, raising the upper base, opening the metal stamp and the metal support plate and extracting the molding, characterized in that the rapid molding fine imprint lithography heating method.

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