JP2005191444A - Pattern transferring equipment, mold cleaning method, and pattern transferring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide pattern transferring equipment that can always keep a mold in a clean condition and secure its high reproducibility, a mold cleaning method, and a pattern transferring method. <P>SOLUTION: Cleaning equipment 80 is provided with a patterning system 10 that cleans a mold 100. A cleaning bath 81 of the cleaning equipment 80 is arranged so as to be within its moving range when the mold 100 suction-held to a holding block 41 is moved by a substrate transport mechanism 30 and a mold driver 50 in X-Y directions relative to a transport base 31. By using such cleaning equipment 80, the mold 100 is moved at a proper time by the substrate transport mechanism 30 and the mold driver 50 to be dipped in the cleaning bath 81, thus ultrasonically cleaning the bottom surface of the mold 100 with a cleaning liquid L. Further, a determining mechanism 90 which determines whether or not the mold 100 needs cleaning is provided so that the cleaning of the mold 100 is automated based on the determination of the determining mechanism 90. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pattern transfer apparatus, a mold cleaning method, and a pattern transfer method.

  Conventionally, a reduction projection exposure method is generally used to form a fine circuit pattern typified by an LSI (Large Scale Integrated Circuit) on a semiconductor substrate (hereinafter simply referred to as a substrate). This method uses an exposure apparatus called a stepper to project and expose a circuit pattern drawn on a reticle (mask) onto a resist surface on a substrate through a reduction optical system and repeat the exposure over the entire substrate. A predetermined fine circuit pattern is formed on the substrate.

In order to increase the degree of integration of the substrate thus formed, it is necessary to reduce the line width of the circuit pattern, and it is expected that the current main line width will be 130 nm and the line width will be 100 nm or less in the future. ing.
In order to cope with this, it is necessary to shorten the wavelength of the light source used for projection exposure. Even in the present situation, each exposure apparatus manufacturer has ultraviolet (UV) light, far ultraviolet (DUV) light, extreme ultraviolet (EUV) light, etc. Development of an exposure apparatus that uses light of a short wavelength as a light source is in progress.

However, when short-wavelength light such as an ultraviolet laser light source is used as a light source, distortion or light source noise is caused by a slight temperature change or external vibration in a lens, a mirror, a light source, etc. constituting the projection optical system of the exposure apparatus. For this reason, the exposure apparatus is required to have a highly accurate temperature control and vibration isolation structure. As a result, the reduction projection type exposure apparatus constituted by such a series of apparatuses has a very high apparatus price (for example, several 1 billion yen). In addition, since the exposure apparatus itself becomes large, installation space and power consumption tend to increase.
As a result, the production cost of the substrate manufactured using the reduction projection type exposure apparatus is increased.

Nanoimprinting process technology was introduced as a technique for forming an ultrafine pattern on a substrate for the purpose of preventing such an increase in apparatus size and process cost (see, for example, Non-Patent Document 1). .
This process uses a mold with the pattern to be formed on the surface, heats the substrate to a temperature exceeding the glass transition temperature of the resist material provided on the substrate, and presses the mold against the substrate surface in that state. This is a method of transferring. This method does not require an expensive laser light source or optical system, and accurately transfers the shape built in the mold as it is despite the simple structure based on the heater and press device. There is a report that a thin line having a line width of about 20 nm has already been formed by this method (see, for example, Non-Patent Document 2).

G. M. Whitesides, J. C. Love, “New Technology for Creating Nanostructures”, “Nikkei Science”, Nikkei Inc., December 1, 2001, Vol. 31, No. 12, p. 30-41 C. M. Sotomayor, et. Al., “Nanoimprint lithography: an alternative nanofabrication approach”, “Materials Science & Engineering C”, Elsevier Science, 2002 (2002), 989, p. 1-9

By the way, using the nano-imprinting process technology as described above, if mass production is actually performed, the residue and residue of the material that forms the substrate will adhere to the mold if the transfer is repeated many times. There is a problem that it causes a decrease in the quality and causes a foreign matter defect.
For this reason, it is necessary to clean the mold at an appropriate timing, but the mold used in the nanoimprinting process is naturally small and the pattern is fine, so it is difficult to manually clean the mold. . In order to reliably perform cleaning, it is preferable to remove the mold from the apparatus. In this case, however, when the mold is attached to the apparatus after cleaning, it takes time to adjust the mounting position. This is because, in order to obtain high reproducibility of the pattern, it is necessary to attach the mold to the apparatus with high accuracy. Needless to say, it is not preferable that the throughput is significantly reduced by cleaning the mold.
The present invention has been made on the basis of such a technical problem. A pattern transfer apparatus, a mold cleaning method, and a pattern transfer method capable of always maintaining a mold in a clean state and ensuring high reproducibility. The purpose is to provide.

For this purpose, the pattern transfer apparatus of the present invention is a pattern transfer apparatus for transferring a pattern formed on a mold to an object to be processed, and holds an object holding unit for holding the object to be processed and the mold. A mold holding unit, a moving mechanism that relatively moves the mold holding unit and the object holding unit in at least two directions, and at least a pattern surface of the mold that is provided in the movement range of the mold holding unit by the moving mechanism and held by the mold holding unit And a washing section for washing the water.
In such a pattern transfer device, the pattern formed on the mold is obtained by relatively moving the mold held by the mold holding unit in at least two directions with respect to the workpiece held by the object holding unit. Is transferred to the workpiece.
Then, at an appropriate timing, the mold held by the mold holding unit is moved relative to the cleaning unit, and at least the pattern surface is cleaned by the cleaning unit to remove residues and residues attached to the mold. it can. At this time, since the cleaning unit is provided within the moving range of the mold holding unit by the moving mechanism, cleaning can be performed without removing the mold from the mold holding unit.
The cleaning unit can include a cleaning tank in which the cleaning liquid is stored, and an ultrasonic vibration source that applies ultrasonic vibration to the cleaning liquid in the cleaning tank, and thereby the mold can be ultrasonically cleaned.
In addition, a mold vibration part that applies ultrasonic vibration to the mold held by the mold holding part is further provided, and at the cleaning part, at least the pattern surface of the mold is immersed in the cleaning liquid, and the mold vibration part is At least the pattern surface of the mold may be cleaned by applying sonic vibration.

The timing for cleaning the mold may be any timing. For example, the mold may be automatically cleaned at a predetermined interval.
Further, if an observation unit for observing the pattern surface of the mold held by the mold holding unit is provided, for example, when the operator observes the pattern surface with this observation unit and determines that the cleaning is necessary, the cleaning unit It is also possible to perform cleaning in
Further, based on the observation image of the pattern surface of the mold by the observation unit, the cleaning control unit determines whether or not the mold needs to be cleaned. Alternatively, the mold holder may be moved relative to the mold holder, and the mold held by the mold holder may be cleaned by the cleaning unit. By doing so, it is possible to automatically perform from the determination of whether or not the mold needs to be cleaned to the execution of the cleaning when the cleaning is necessary.

By the way, in order to transfer the pattern of the mold to the workpiece, conventionally, as described above, the workpiece is heated to the glass transition point or higher, and the mold is pressed against the workpiece in this state to transfer the pattern. Then, after the workpiece is cooled below the glass transition point, a series of steps are performed in which the mold is separated from the workpiece and demolded.
In such a process, the object to be processed is heated and cooled. For this purpose, a method of heating and cooling the entire object to be processed with a heater is used. This heater is usually provided on a table that supports a workpiece. When the workpiece becomes larger, the heat capacity of the workpiece and the table to be heated and cooled by the heater increases. As a result, the workpiece is heated and cooled, and the entire workpiece is heated to a uniform temperature. It takes several tens of seconds to several minutes to make it.
This is a major factor that hinders the high throughput of pattern transfer.

  For such a problem, the pattern transfer apparatus of the present invention can further include a heating unit that heats the mold held by the mold holding unit. In that case, the mold heated by the heating unit is pressed against the workpiece held by the holding unit by the moving mechanism, so that the workpiece is heated to near or above the glass transition temperature and formed into a mold. The transferred pattern is transferred to the object to be processed.

After the mold pattern is pressed against the workpiece surface and transferred, the mold is pulled away from the workpiece surface.In the so-called mold release process, if the mold and workpiece are not released smoothly, they are formed on the workpiece. Phenomenon such as the pattern collapsed or the material on the workpiece side comes into close contact with the mold and peels off. As a result, there arises a problem that the pattern reproduction accuracy (repetition accuracy) decreases.
Moreover, when performing pattern transfer to various devices in the above-described process, naturally, high throughput is required when industrialization is actually attempted. When the above phenomenon occurs, it is necessary to take measures against this, and hinder high throughput.
In order to form various patterns, for example, a pattern with a so-called high aspect ratio having a large depth and height with respect to the width of the hole, groove, column or wall, such as a diameter of 100 nm and a depth of 5 μm, must be formed. There are things that must be done. The above problem becomes more prominent in such a case.

As countermeasures against such problems, the mold and workpiece can be processed by applying a lubricant (release agent) to the mold or forming an oxide film as in the pattern forming process using a normal mold. It is conceivable to reduce the friction between the molds or to extremely slow the moving speed of the mold at the time of mold release so that no abrupt peeling force is generated between the mold and the workpiece.
However, with these countermeasures, the lubricant on the mold surface adheres to the workpiece side while pattern forming is repeated many times, and the lubricant is reduced, or the oxide film is worn due to friction with the workpiece side. To do. For this reason, it is necessary to periodically replenish the lubricant or to check the wear state of the oxide film as appropriate, and to re-form the oxide film as necessary, but this hinders high throughput. In particular, when an integrated circuit is manufactured, this problem becomes more noticeable because the mold is small relative to the workpiece and the mold is pressed many times on one workpiece.
In addition, when the workpiece is such that a chemical reaction is caused by a flow path for flowing a chemical solution or a hole or groove formed, adhesion of a mold release agent is preferable because it affects the chemical solution and the chemical reaction. It goes without saying that it is not.
Furthermore, the method of slowing the moving speed of the mold at the time of mold release is not preferable because it directly leads to a decrease in throughput.

Therefore, in the pattern transfer apparatus of the present invention, when the mold and the workpiece are separated after the mold is pressed against the workpiece, the control unit causes the vibration to be applied to the mold or the object holder by the vibration mechanism. It can also be controlled.
This makes it possible to reduce the adhesion between the two when the mold is separated from the workpiece.
The vibration applied by the vibration mechanism may be any frequency and amplitude as long as the adhesion between the mold and the workpiece can be reduced, but the pattern diameter and width are very small. It is preferable to apply ultrasonic vibration. Here, as the ultrasonic vibration, vibration having a frequency higher than about 20 kHz, such as 19.2 kHz, can be used.

  The present invention can also be understood as the following pattern transfer apparatus. That is, a mold for forming a predetermined pattern on the workpiece, an object holder that holds the workpiece, an excitation mechanism that applies vibration to the mold or the object holder, and a heating unit that heats the mold A moving mechanism that relatively moves the mold and the object holding unit in at least two directions, and a cleaning unit that is provided within a moving range of the mold by the moving mechanism and that cleans at least the pattern surface of the mold. The heated mold is moved relative to the workpiece with a moving mechanism and pressed against the workpiece, so that the workpiece is heated to near or above the glass transition temperature. It is characterized by forming a pattern.

The present invention can also be understood as a method for cleaning the pattern surface of a mold in a pattern transfer apparatus that transfers a pattern formed on the mold to a workpiece. This method includes a step of moving the mold to a position facing a cleaning tank provided in the range within a range in which the mold can move relative to the workpiece, and at least a pattern surface of the mold in the cleaning tank. It includes a step of immersing in a cleaning liquid and a step of applying ultrasonic vibration to the cleaning liquid or the mold and ultrasonically cleaning the pattern surface of the mold with the cleaning liquid.
At this time, the method further comprises a step of observing the pattern surface of the mold at a predetermined timing and determining whether or not the mold needs to be cleaned based on the observation result, and determining that the cleaning is necessary in the determining step. In this case, it is effective to move the mold and the washing tank relative to each other and wash the mold in the washing tank.

  If the present invention is regarded as a pattern transfer method for transferring a predetermined pattern onto a substrate with a mold, this method includes a heating step of heating the mold to a predetermined temperature based on the glass transition temperature of the substrate, and a mold. A pattern transfer step of pressing the substrate to transfer the pattern, a step of observing the pattern surface of the mold at a predetermined timing, and a step of determining whether or not the mold needs to be washed based on the observation result And the step of cleaning the mold in a cleaning tank provided in a range in which the mold can be relatively moved with respect to the object to be processed.

  According to the present invention, the mold can always be kept clean. In addition, by providing a cleaning unit and a cleaning tank within the moving range of the mold, it is possible to clean the mold without removing it from the mold holding unit, minimizing throughput degradation and ensuring high reproducibility. Can do. Furthermore, the mold cleaning can be performed at an optimal timing by automatically performing the mold cleaning when it is determined that the mold needs to be cleaned based on the observation image of the pattern surface of the mold.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
1 and 2 are diagrams for explaining the overall configuration of the pattern transfer apparatus according to the present embodiment.
As shown in FIGS. 1 and 2, the pattern transfer apparatus 10 forms a pattern on a substrate 200 by transferring a mold 100 on which a predetermined pattern is formed by unevenness onto a substrate (processing object) 200. It is.
The pattern transfer apparatus 10 includes a substrate holding unit (object holding unit) 20 that holds a substrate 200 to be processed, a substrate moving mechanism (moving mechanism) 30 that moves the substrate holding unit 20 in one direction, and a substrate 200. A mold holder 40 for holding a mold 100 for forming a predetermined pattern on the mold, and a mold drive mechanism (press mechanism, moving mechanism) 50 for driving the mold 100 held in the mold holder 40 in two directions. I have.

As shown in FIGS. 1 and 2, the substrate holder 20 holds the substrate 200 in a substantially horizontal state, and includes a table 21 having a support surface 21a on the upper surface.
The table 21 has a large number of vacuum holes (not shown) formed in the support surface 21a. By applying a negative pressure from a negative pressure source (not shown) to the vacuum holes, the substrate 200 is formed on the support surface 21a. Can be adsorbed and held.
As shown in FIG. 3, the table 21 has a built-in heater 22 for heating the held substrate 200. The operation of the heater 22 is controlled by a controller (control unit) (not shown) so as to maintain the substrate 200 on the table 21 at a predetermined constant temperature. As this heater 22, for example, a heat transfer heater or a ceramic heater described in detail later can be suitably used.

As shown in FIG. 1, the substrate moving mechanism 30 moves the table 21 holding the substrate 200 in one direction (hereinafter referred to as a support surface 21 a of the table 21, that is, a plane parallel to the surface of the substrate 200 to be held). This is referred to as the Y direction). The substrate moving mechanism 30 has a lower base 32 provided on a base 31.
Both ends of the lower base 32 are slidably supported by a pair of linear guides 33 extending in one direction, and by a linear motor 34 provided in parallel between the two linear guides 33, 33, Advancing and retreating in the Y direction along the linear guides 33 and 33 is performed.
Further, an upper base 35 is provided on the lower base 32, and the upper base 35 is provided with a mechanism (not shown) for adjusting the angle in the XY plane.

As shown in FIG. 4, the mold holding portion 40 includes a support surface 41 a on the lower surface, and a holding block 41 that holds the mold 100 with the support surface 41 a.
The holding block 41 incorporates a heater (heating unit) 42 for heating the mold 100. The heater 42 is preferably a so-called ceramic heater which is formed of a ceramic material such as aluminum nitride and has a wiring as a heater electrode embedded therein. In such a holding block 41, the temperature rises when a current is supplied from a power source (not shown) to the heater electrode, and the temperature falls when the current is cut. The ceramic heater is a heater having a very quick response, for example, whose temperature rises to nearly 1000 degrees in 10 seconds. Current supply from the power supply to the heater electrode is controlled by a controller (not shown).

And the holding block 41 can also be equipped with the cooling block (cooling part) 43 integrally on the upper surface side. The cooling block 43 is made of a metal having high thermal conductivity such as aluminum or copper, and a flow path 44 is formed inside the cooling block 43 so that a coolant such as cooling water can flow through the flow path 44. It has become.
Such a cooling block 43 has a function of cooling the holding block 41 and the mold 100 by flowing a coolant through the flow path 44.

As shown in FIGS. 1 and 2, the mold driving mechanism 50 has two holding blocks 41 that suck and hold the mold 100 as described above perpendicular to the moving direction (Y direction) of the table 21 by the substrate moving mechanism 30. It is moved in the direction (hereinafter referred to as X and Z directions).
The mold drive mechanism 50 includes two fixed blocks 52 and 52 supported on the side walls 51 and 51 provided on both sides of the base 31, and a moving frame that moves in the X direction with respect to the fixed blocks 52 and 52. 53 and an elevating mechanism 54 that is provided on the moving frame 53 and moves the holding block 41 up and down.
The fixed blocks 52 and 52 are rectangular blocks that are long in the X direction, and are fixed on the side walls 51 and 51 with an interval in the Y direction. Each fixed block 52 is provided with a linear guide 55 extending in the horizontal direction orthogonal to the moving direction of the table 21, that is, in the X direction.

  As shown in FIG. 2, the moving frame 53 has a substantially rectangular tube shape surrounding the front and rear fixed blocks 52 and 52, and is moved in the X direction by the linear guides 55 and 55 of the front and rear fixed blocks 52 and 52. It is supported freely. The moving frame 53 is moved in the X direction along the linear guides 55 and 55 by a linear motor 56 provided between the fixed blocks 52 and 52.

The elevating mechanism 54 includes a motor 57 fixed to the top plate 53 a of the moving frame 53, a ball screw 58 extending in a direction orthogonal to the support surface 21 a of the table 21, that is, a vertical direction, and a bearing portion 59 that meshes with the ball screw 58. And a guide 61 provided between the top plate 53a and the bottom plate 53b of the moving frame 53.
The support base 60 is supported so as to be vertically movable along the guide 61 in the vertical direction, that is, the Z direction. When the ball screw 58 is rotationally driven by the motor 57, the support base 60 is lifted and lowered in the Z direction. .
The holding block 41 is fixedly attached to the lower surface of the support base 60 via an ultrasonic vibration member (vibration mechanism, mold vibration portion) 70.

  As shown in FIG. 3, the ultrasonic vibration member 70 includes a piezoelectric element 71 attached to the lower surface of the support base 60 and an ultrasonic horn 72 attached to the lower surface of the piezoelectric element 71. Here, when an AC voltage is applied to the piezoelectric element 71 by a drive circuit (not shown), the frequency of the AC voltage is the vertical direction, that is, the direction connecting the support base 60 and the holding block 41 (the mold 100 is separated from the substrate 200). (Vibration direction). In the ultrasonic horn 72, the upper end 72a in contact with the piezoelectric element 71 is a fixed end, and the lower end 72b is a free end. As a result, when the piezoelectric element 71 vibrates, the vibration is amplified on the lower end portion 72b side of the ultrasonic horn 72 that is a free end, and the amplitude of the vibration is increased in the mold 100 attached to the lower end portion 72b of the ultrasonic horn 72. Has become the maximum.

Now, as shown in FIG. 4, the mold 100 has an uneven surface 101 for forming a predetermined pattern on the lower surface 100 a thereof.
On the other hand, as shown in FIG. 5A, the substrate 200 to be processed has a substrate shape as it is, for example, a resin material such as polycarbonate or polyimide, a glass material, silicon, gallium arsenide, sapphire, magnesium oxide, or the like. What is missing can be used. Further, as shown in FIG. 5B, the substrate 200 is made of aluminum, gold, silver or the like for forming a resin film, a photoresist, a wiring pattern on the surface of the substrate body 201 made of a silicon wafer, a glass wafer or the like. A metal film or the like on which a thin coating layer 202 is formed can be used.
In the case of FIG. 5A, the pattern is transferred to the surface layer portion of the substrate 200 by the unevenness 101 of the mold 100 shown in FIG. 4, and in the case of the substrate 200 of FIG. 5B, the pattern of the unevenness 101 of the mold 100 is In any case, since the pattern is transferred to the surface layer portion of the substrate 200, the portion to which the pattern is transferred is referred to as “the surface layer of the substrate 200”. It is simply referred to as “part”, and this expression includes both cases of FIGS. 5 (a) and 5 (b).

  In the pattern transfer apparatus 10, the unevenness 101 having a predetermined pattern formed on the lower surface 100 a of the mold 100 is pressed against the substrate 200 with a predetermined pressure, whereby the pattern is transferred and formed only on the surface layer portion of the substrate 200.

Below, the pattern transfer process in the above pattern transfer apparatus 10 is demonstrated. The operation of the pattern transfer apparatus 10 shown below is basically automatically controlled by a controller (not shown).
In the pattern transfer apparatus 10, as shown schematically, as shown in FIG. 6A, the mold 100 is heated above the glass transition temperature of the substrate 200, and in this state, as shown in FIG. 6B. 100 is pressed against the substrate 200 to heat the substrate 200. Then, as shown in FIG. 6 (c), the mold 100 is pressed for a certain time to hold the load, and then the mold 100 is cooled and pulled away from the substrate 200 as shown in FIG. 6 (d). Through this series of steps, the surface layer portion of the substrate 200 is formed into a shape corresponding to the unevenness 101 of the mold 100.

More specifically, first, the predetermined mold 100 is held on the holding block 41. In this state, the mold driving mechanism 50 keeps the holding block 41 at the rising end of the predetermined stroke area, and keeps the mold 100 and the table 21 held by the holding block 41 apart from each other. .
And when the board | substrate 200 used as the process target is set on the table 21, this will be vacuum-sucked.

Thereafter, the mold 100 is pressed against the substrate 200 to transfer a predetermined pattern. Prior to this, as shown in FIG. 7, the controller 22 includes a heater 22 built in the table 21 and a holding block. The heaters 42 provided in 41 are turned on in advance at a predetermined timing S1. A coolant such as cooling water is allowed to flow through the flow path 44 of the cooling block 43.
In this state, that is, before the mold 100 is pressed against the substrate 200, the glass transition of the material that forms the surface layer portion of the substrate 200 is performed by heat conduction from the heater 42 of the holding block 41 and the heater 22 of the table 21. The substrate 200 is maintained at a predetermined temperature T2 that is lower than the glass transition temperature Tg of the material that forms the surface layer portion to be processed of the substrate 200.

  Thereafter, by moving the table 21 and the holding block 41 in the X and Y directions by the substrate moving mechanism 30 and the mold driving mechanism 50, a predetermined region of the substrate 200 attracted and fixed to the table 21 is transferred to the holding block 41. Positioning is performed against the held mold 100.

Subsequently, the mold 100 held by the holding block 41 is moved in the Z direction by the mold driving mechanism 50 to approach the substrate 200 held by the table 21. When the mold 100 comes into contact with the surface of the substrate 200 at a predetermined timing S3 after the unevenness 101 of the mold 100 rises to the predetermined temperature T1, the mold driving mechanism 50 holds the holding block 41 as shown in FIG. The movement of the mold 100 held in is stopped. Then, heat is conducted from the mold 100 in a state where the temperature has risen to the temperature T1 that is equal to or higher than the glass transition temperature Tg to the surface layer portion of the substrate 200, whereby the temperature of the surface layer portion of the substrate 200 is close to the temperature T1 of the mold 100. Rise. At this time, the temperature of the portions other than the surface layer portion of the substrate 200 with which the unevenness 101 of the mold 100 is in direct contact does not increase so much.
As shown in FIG. 6C, the substrate 200 is held by the mold drive mechanism 50 at a timing S4 when the surface layer portion of the substrate 200 rises to a temperature near the glass transition temperature Tg or higher, or at least near the glass transition temperature Tg. The mold 100 held by the block 41 is further moved to the substrate 200 side. As a result, the mold 100 bites further into the surface of the substrate 200, and the pattern of the unevenness 101 of the mold 100 is transferred to the surface layer portion of the substrate 200.

By the way, in the operation as described above, the movement of the mold 100 by the mold drive mechanism 50 is stopped between the timings S3 and S4 while the mold 100 is in contact with the surface of the substrate 200. That is, between the timings S3 and S4, a predetermined load that does not give permanent distortion to the substrate 200 in a state where the surface layer temperature of the substrate 200 is lower than the glass transition temperature Tg by the control of the controller functioning as a load controller. F1 is in a state applied from the mold 100.
After timing S4, the mold driving mechanism 50 moves the mold 100 to the substrate 200 side, so that the temperature of the surface layer portion of the substrate 200 from the mold 100 is higher than the glass transition temperature Tg with respect to the substrate 200. A predetermined load F2 different from the load F1 for applying permanent deformation and performing molding is applied.
In this way, the load applied to the substrate 200 from the mold 100 is varied in two stages by the loads F1 and F2, and when the load F1 is in a state where the mold 100 and the substrate 200 are in contact, Heat is conducted to the substrate 200 side to soften the surface layer portion of the substrate 200, and then the load is transferred to the load F2 to perform molding with the mold 100.

  Now, after the timing S4, the current supply amount to the heater 42 of the holding block 41 is decreased at a timing S5 when a predetermined time t set in advance elapses. Thereby, the temperature of the holding block 41, the mold 100, and the substrate 200 is lowered. At this time, the cooling block 43 having a glass transition temperature Tg or less is provided on the upper surface side of the holding block 41. For example, the temperature of the mold 100 and the substrate 200 quickly decreases to near the temperature T2 of the table 21.

Subsequently, after timing S5 when the amount of current supplied to the heater 42 of the holding block 41 is reduced, at a timing S6 set a predetermined time before a timing S7 for starting mold release described later, the piezoelectric of the ultrasonic vibrating member 70 A voltage is applied to the element 71 to generate vibration. As a result, the ultrasonic horn 72 applies vibrations to the mold 100 via the holding block 41.
At this time, in the piezoelectric element 71, for example, in the vertical direction, that is, in the direction in which the mold 100 and the substrate 200 are separated from each other and approach each other, for example, at a frequency of 20 kHz, the number of molding depths (heights) It is driven to generate ultrasonic vibrations having an amplitude of 1 or less.

  Then, at timing S7 after a predetermined time has elapsed from timing S6 at which ultrasonic vibration is started to be applied to the mold 100, the mold driving mechanism 50 is operated to hold the mold 100 on the table 21, as shown in FIG. The substrate is separated from the formed substrate 200 and released.

Thereby, a predetermined pattern constituted by the unevenness 101 of the mold 100 is transferred and formed on the surface layer portion of the substrate 200.
By the way, the vibration applied to the mold 100 by vibrating the piezoelectric element 71 is stopped by cutting off the voltage supply to the piezoelectric element 71 at a predetermined timing after the mold 100 starts to move away from the substrate 200. Note that this timing may be set to any timing as long as the mold 100 starts to move away from the substrate 200. For example, the mold drive mechanism 50 moves the mold 100 away from the substrate 200. The movement may be performed almost simultaneously, or may be performed before the mold 100 is completely separated from the substrate 200 or after the mold 100 is completely separated from the substrate 200.

As described above, after one pattern transfer is performed on the substrate 200 with the mold 100, the current to be supplied to the heater 42 of the holding block 41 is increased at a predetermined timing S2, thereby being held by the holding block 41. The substrate 200 is moved to the next pattern transfer position by the substrate moving mechanism 30 while the mold 100 is again set to the temperature T1 equal to or higher than the glass transition temperature Tg.
The timing S2 for increasing the current flowing to the heater 42 of the holding block 41 is such that the mold 100 is subjected to glass transition before the unevenness 101 of the mold 100 contacts (presses) the surface of the substrate 200 at the next pattern transfer position. Any timing may be used as long as the temperature rises to a predetermined temperature T1 equal to or higher than the temperature Tg.
Thereafter, by performing the steps such as pressing, cooling, and releasing the mold 100 in the same manner, a pattern can be formed at another position.
Then, the pattern of the mold 100 can be sequentially transferred to a plurality of locations on the substrate 200 by sequentially repeating the series of steps described above.

By the way, when the mold 100 is pressed against the substrate 200 as described above, the temperature of the substrate 200 is set to be constant lower than the glass transition temperature Tg of the material of the surface layer portion to be processed. Was set higher than the glass transition temperature Tg. For example, when the substrate 200 is a polycarbonate resin (PC), since the glass transition temperature Tg of the polycarbonate resin is about 150 ° C., the temperature T2 of the substrate 200 (table 21) is set to about 140 ° C. below the glass transition temperature Tg. The temperature T1 of the mold 100 is set to about 160 to 170 ° C. above the glass transition temperature Tg. When the mold 100 is pressed against the substrate 200 in this state, the temperature of the mold 100 is transmitted to the surface layer portion of the substrate 200, the temperature rises from the surface layer portion of the substrate 200, and is gradually transmitted to the whole.
For example, it is preferable to set the temperature T1 higher by about 20 ° C. and the temperature T2 lower by about 30 to 50 ° C. than the glass transition temperature Tg of the material forming the surface layer portion of the substrate 200. Of course, the set temperature varies depending on the type of material, and is not uniquely determined.
In a resin or glass material constituting the substrate 200, a state where the glass transition temperature Tg is exceeded is very easily deformed by an external stress, that is, is easy to be molded, and thus exceeds the glass transition temperature Tg. While maintaining the state, the load is increased on the mold 100 and pressed against the substrate 200. Then, the substrate 200 is deformed along the shape of the mold 100 and is stabilized in a state where the shape of the unevenness 101 is reversed and transferred.
Thereafter, the temperature of the mold 100 is lowered to the glass transition temperature Tg or lower, and the temperature of the substrate 200 in contact with the mold 100 is lowered. In the state below the glass transition temperature Tg, the substrate 200 is not easily deformed as in the initial state, that is, the substrate is cured along the shape of the projections and depressions 101 of the mold 100 and the pattern is fixed. When the mold 100 is pulled away from the substrate 200 in a state where the substrate 200 is equal to or lower than the glass transition temperature Tg, the surface layer portion of the substrate 200 is in a state where the shape of the unevenness 101 of the mold 100 is inverted and transferred, that is, the unevenness 101 of the mold 100. A pattern having a reversed shape is formed.

In addition, after forming a pattern on the substrate 200 with the mold 100, ultrasonic vibration is applied to the mold 100 when the mold 100 is released from the substrate 200. As a result, a relative displacement occurs between the mold 100 and the substrate 200, and the static friction force acting between the mold 100 and the substrate 200 is changed to a dynamic friction force immediately before that, that is, immediately before releasing the mold. Can do. As is well known, since the dynamic friction force is smaller than the static friction force, the adhesion force between the mold 100 and the substrate 200 can be reduced, thereby suppressing the occurrence of biting between the mold 100 and the substrate 200 and releasing the mold. It is possible to perform smoothly. As a result, even when a pattern having a high aspect ratio is formed, the pattern formed on the substrate 200 can be prevented from being collapsed, and the material of the substrate 200 can be prevented from adhering to the mold 100. It is possible to improve and increase the throughput by suppressing the maintenance frequency of the mold 100 and the like, and to suppress the maintenance cost.
In addition, it is not necessary to apply a lubricant or form an oxide film, and the bite between the mold 100 and the substrate 200 can be prevented, so that the substrate 200 to be formed is particularly suitable for flowing a chemical solution or causing a chemical reaction. Even in the case of having a pattern, this technique can be used very favorably without affecting the chemical solution or chemical reaction.

  The pattern transfer apparatus 10 is configured such that ultrasonic vibration is applied to the mold 100 only at the time of mold release, and no ultrasonic vibration is applied in the process of pressing the mold 100. In the step of pressing the mold 100, the surface layer portion of the substrate 200 is heated to the glass transition temperature Tg or higher and is softened. Therefore, when ultrasonic vibration is applied to the mold 100 in this state, the pattern size is particularly small. A pattern in which the amplitude of vibration is added to the size of the unevenness 101 of the mold 100 is formed as a pattern, and the pattern reproduction accuracy may be lowered. On the other hand, as described above, by applying ultrasonic vibration to the mold 100 only at the time of mold release, it is possible to avoid a decrease in pattern reproduction accuracy.

Further, after the mold 100 set to the temperature T1 equal to or higher than the glass transition temperature Tg of the surface layer portion of the substrate 200 is pressed against the substrate 200 and the pattern of the mold 100 is transferred, the mold 100 is cooled to a temperature T2 that is equal to or lower than the glass transition temperature Tg. The mold 100 is separated from the substrate 200.
In this way, heat is directly applied only from the mold 100 in contact with the surface layer portion of the substrate 200 on which the pattern is formed, not to the entire substrate 200 but only to the surface layer portion that is the processing target portion. The heating / cooling time can be shortened. Furthermore, when the mold 100 is smaller than the substrate 200, not only the entire area of the substrate 200 but only a local portion where the mold 100 hits is heated. This also contributes to heating in a short time. Can do.
This makes it possible to increase the efficiency of the thermal cycle applied when the pattern is transferred to the substrate 200 by the mold 100, thereby increasing the throughput and saving energy used. Further, the mold 100 that sequentially transfers the pattern to the substrate 200 a plurality of times with one mold 100 can be small in size, and accuracy and temperature control can be easily performed as compared with a large one, and the cost of the mold 100 can be reduced. It can be greatly reduced.

Moreover, since the pattern transfer apparatus 10 can be realized with a mechanical structure without using an optical system or a light source, it can be manufactured at a much lower cost than a conventional stepper or the like. It is also possible to reduce the size.
In this way, pattern transfer to the substrate 200 can be performed with high efficiency and at low cost.

In such a pattern transfer apparatus 10, for example, a wafer (processing object) 200 </ b> A as shown in FIG. 8 can be applied as the substrate 200 to be processed. A plurality of patterns P can be transferred onto such a wafer 200A. Thereby, the area of the wafer 200A can be increased, and the handling time for changing the wafer 200A to the table 21 can be saved, so that the production cost of one molded product can be reduced.
In addition, as the substrate 200, a photonic crystal (processing object) 200B in which minute dot shapes shown in FIG. 9 are arranged at a constant period, a semiconductor electronic circuit substrate having a predetermined wiring pattern, Furthermore, a substrate (object to be processed) 200C having a minute flow path 203 as shown in FIG. 10 can be applied.

  As shown in FIG. 1, in the present embodiment, the pattern transfer apparatus 10 as described above is provided with a cleaning device (cleaning unit) 80 for cleaning the mold 100. The cleaning device 80 is provided on the base 31, for example, and includes a cleaning tank 81 in which the cleaning liquid L is stored, and an ultrasonic vibration source (not shown) that applies ultrasonic vibration to the cleaning tank 81. . The cleaning tank 81 can be provided in a place other than the base 31, but it is preferable to provide the cleaning tank 81 in a non-movable fixed portion so that the cleaning liquid L does not spill.

  The cleaning tank 81 is within a movable range when the mold 100 attracted and held by the holding block 41 is moved in the X and Y directions with respect to the base 31 by the substrate moving mechanism 30 and the mold driving mechanism 50. In the position. In addition, the cleaning liquid L stored in the cleaning tank 81 has a movable surface when the mold 100 is sucked and held by the holding block 41 by the mold driving mechanism 50 and moved in the Z direction with respect to the base 31. In other words, the unevenness 101 which is a pattern formed on at least the lower surface 100 a of the mold 100 is set so as to be immersed in the cleaning liquid L.

  With such a cleaning apparatus 80, the mold 100 is moved by the substrate moving mechanism 30 and the mold driving mechanism 50 at an appropriate timing, immersed in the cleaning tank 81, and an ultrasonic vibration source (not shown) is operated, thereby allowing the mold to operate. The unevenness 101 on the lower surface 100a of 100 can be ultrasonically cleaned with the cleaning liquid L.

  The cleaning device 80 is provided with a supply pipe 83 that supplies the cleaning liquid L to the cleaning tank 81 and a drain pipe 84 that discharges the cleaning liquid L from the cleaning tank 81, and performs appropriate operations from outside the pattern transfer apparatus 10. Thus, the cleaning liquid L in the cleaning tank 81 can be exchanged or circulated as needed.

  As the cleaning liquid L, pure water, alcohol such as acetone, isopropyl alcohol, or the like can be used. Further, when the surface layer portion of the substrate 200 is formed of a resin, the resin material is dissolved in a solvent to form a paste, and this is spread on the surface of the substrate body 201 by a spin coating method. Can also be used as the cleaning liquid L. In this way, the residue attached to the mold 100 is the residue of the surface layer portion of the substrate 200, so that it can be easily dissolved and removed.

The mold 100 is cleaned by the cleaning device 80 as described above, for example, the operator observes the mold 100 at an appropriate timing, and the worker performs a predetermined operation according to the determination result made by the worker based on this. The pattern transfer apparatus 10 can be made to clean the mold 100. At this time, the operator may observe the mold 100 directly, but a camera or the like is provided as an observation unit for observing the mold 100 at an appropriate position in the pattern transfer apparatus 10. It is preferable that the sent image is viewed from outside the pattern transfer apparatus 10 and actually observed and judged.
In addition, conditions can be determined in advance during a test operation or the like, and can be performed for each number of shots of the mold 100 set based on the conditions. In that case, when the predetermined number of shots is reached, an alarm signal is notified, and based on the alarm signal, the operator may perform a predetermined operation to execute the cleaning of the mold 100, or the pattern transfer device 10 The controller 100 may be programmed in advance so that the mold 100 is automatically cleaned by the cleaning apparatus 80 every predetermined number of shots.

Furthermore, the pattern transfer apparatus 10 can be provided with a determination mechanism (cleaning control unit) 90 that determines whether or not the mold 100 needs to be cleaned and automatically executes the cleaning of the mold 100 based on the determination result. .
For this purpose, as shown in FIG. 1, imaging means such as a CCD (Charge Coupled Device) camera (observation unit) 91 is provided at a predetermined position on the base 31 side, for example, the upper surface of the table 21. The CCD camera 91 is set so as to capture a vertically upward image. When the mold 100 is positioned so as to face the CCD camera 91, the CCD camera 91 captures the unevenness 101 on the lower surface 100a of the mold 100. . The CCD camera 91 is preferably provided on the side close to the cleaning tank 81. As will be described later, it is determined whether or not the mold 100 is to be cleaned based on the imaging result of the CCD camera 91. When the mold 100 is to be cleaned, the movement distance after imaging by the CCD camera 91 is determined. This is because the time required for cleaning can be shortened.

  The determination mechanism 90 includes a determination circuit (not shown) that analyzes the image of the mold 100 captured by the CCD camera 91 and determines whether or not cleaning is necessary. In this determination circuit (not shown), the image of the mold 100 in a normal state stored in advance and the image of the mold 100 captured by the CCD camera 91 are compared by an appropriate image processing method, and the mold 100 needs to be cleaned. It is determined whether or not. Specifically, in the image of the mold 100 picked up by the CCD camera 91, when the difference from the image of the mold 100 in the normal state exceeds a predetermined threshold due to debris attached to the mold 100, the mold 100 It is determined that cleaning is necessary.

When it is determined in the determination circuit (not shown) that the mold 100 needs to be cleaned, the determination mechanism 90 operates the substrate moving mechanism 30 and the mold drive mechanism 50 so that the mold 100 is cleaned by the cleaning tank 81 of the cleaning device 80. And ultrasonic cleaning with the cleaning liquid L is automatically performed.
By providing such a determination mechanism 90, it is possible to automatically clean the mold 100 at an appropriate timing according to the condition of the mold 100.

  The determination mechanism 90 can automatically determine whether or not the mold 100 needs to be cleaned every predetermined number of shots. Further, when the pattern transfer to the substrate 200 is completed and the next substrate 200 is exchanged, if the CCD camera 91 is installed at a position facing the position where the mold 100 is waiting, the mold is placed at a position facing the CCD camera 91. Since it is not necessary to move 100, the determination can be performed while the substrate 200 is being replaced. In this way, it is possible to determine whether or not cleaning is necessary every time one substrate 200 is processed.

In the above embodiment, the mold 100 is vibrated by the ultrasonic vibration member 70, but a similar mechanism may be provided on the side of the table 21 that holds the substrate 200.
Further, although the ultrasonic vibration source is provided in the cleaning tank 81 of the cleaning device 80, it is possible to adopt a configuration in which the mold 100 is ultrasonically vibrated in the cleaning liquid L by the ultrasonic vibration member 70 on the mold 100 side. . In this case, the ultrasonic vibration source on the cleaning device 80 side can be omitted.
Further, the pattern transfer is performed by pressing the heated mold 100 against the substrate 200, but instead, the substrate 200 side may be heated as usual.

Other than this, as long as it does not depart from the gist of the present invention that the mold 100 is cleaned by the cleaning device 80 in the pattern transfer device 10, the other portions can be changed to any configuration.
For example, the temperature profile applied to the mold 100 may be changed by the heater 42, or the heater is provided not on the mold 100 side but on the substrate 200 side as in the prior art, so that the substrate 200 is heated to the vicinity of the glass transition point. It is good.
Further, although the heater 42 of the holding block 41 is a ceramic heater and the cooling block 43 is a cooling structure using a refrigerant, it is not particularly limited as long as it can be heated and cooled at high speed. Heating by sound waves, cooling by Peltier elements, or the like may be used.
Furthermore, a configuration without such a cooling block 43 is also possible.

In the pattern transfer apparatus 10, the substrate 200 is moved in the Y direction by the substrate moving mechanism 30 and the mold 100 is moved in the X and Z directions by the mold driving mechanism 50. However, the present invention is not limited to this. The drive mechanism can also use a hydraulic mechanism, a pneumatic mechanism, or the like.
In addition, the pattern transfer is repeated a plurality of times while the mold 100 is moved relative to the substrate 200. However, the pattern transfer is performed only once with the mold 100 for one substrate 200. May be.

In addition, the material and manufacturing method of the mold 100 are not particularly limited as long as a fine pattern can be formed. On the other hand, the substrate 200 is formed by integrating the molding material of the surface layer portion and the substrate, for example, a resin substrate or a glass substrate, or a thin molding material formed on the substrate, for example, a silicon substrate or a glass substrate. The combination thereof, such as a resin film, is not particularly limited.
In addition, the present invention can be applied to a configuration in which an ultraviolet curable resin (photocurable resin) is used for at least the surface layer portion of the substrate 200 and ultraviolet rays are irradiated from an ultraviolet light source. Such an ultraviolet light source may be provided separately from the pattern transfer apparatus 10, but the substrate 200 is formed of a material that transmits ultraviolet light, and an ultraviolet light source is provided on the lower side of the substrate 200, that is, on the table 21. By transmitting the light from the light source from the back side of the substrate 200, the UV curable resin in the surface layer portion can be cured to fix the pattern.
Furthermore, the processing object is not limited to the substrate 200, and the present invention can be applied to other processing objects. For example, even when pattern transfer is performed without heating the object to be processed or the mold side, the same effects as in the above embodiment can be obtained by applying the present invention.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

It is a front view which shows the pattern transfer apparatus in this Embodiment. It is a sectional side view of FIG. It is a figure which shows the structure of a board | substrate holding | maintenance part, a type | mold holding | maintenance part, and an ultrasonic vibration member. It is sectional drawing which shows the structure of a type | mold holding part. It is a figure which shows the example of the board | substrate used as a process target object. It is a figure which shows the flow of the pattern process with respect to the board | substrate by a type | mold. It is a figure which shows the timing of the temperature change of a heater, a board | substrate, a board | substrate surface layer part, ultrasonic vibration excitation, and mold release at the time of pattern transfer. It is a figure which shows an example of the board | substrate which forms a pattern. It is a figure which shows another example of the board | substrate which forms a pattern. It is a figure which shows another example of the board | substrate which forms a pattern.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Pattern transfer apparatus, 20 ... Substrate holding part (object holding part), 21 ... Table, 30 ... Substrate moving mechanism (moving mechanism), 31 ... Base, 40 ... Mold holding part, 41 ... Holding block, 42 ... Heater (heating unit), 50... Mold drive mechanism (press mechanism, moving mechanism), 54... Lifting mechanism, 70... Ultrasonic vibration member (vibration mechanism, mold vibration unit), 80. ... Cleaning tank, 90 ... Determination mechanism (cleaning control unit), 91 ... Camera (observation unit), 100 ... Mold, 101 ... Concavity / convexity, 200 ... Substrate (object to be processed), L ... Cleaning liquid, P ... Pattern

Claims (11)

A pattern transfer device for transferring a pattern formed on a mold to a workpiece,
An object holding unit for holding the object to be processed;
A mold holding unit for holding the mold;
A moving mechanism for relatively moving the mold holding part and the object holding part in at least two directions;
A cleaning unit that is provided within a moving range of the mold holding unit by the moving mechanism and that cleans at least a pattern surface of the mold held by the mold holding unit;
A pattern transfer apparatus comprising: The cleaning unit includes a cleaning tank in which a cleaning liquid is stored,
An ultrasonic vibration source for applying ultrasonic vibration to the cleaning liquid in the cleaning tank;
The pattern transfer apparatus according to claim 1, further comprising: A mold vibration part for applying ultrasonic vibration to the mold held by the mold holding part;
The cleaning unit applies at least the pattern surface of the mold by applying ultrasonic vibration to the mold with the mold vibration unit in a state where at least the pattern surface of the mold held by the mold holding unit is immersed in a cleaning liquid. The pattern transfer apparatus according to claim 1, wherein cleaning is performed.   The pattern transfer apparatus according to claim 1, further comprising an observation unit that observes a pattern surface of the mold held by the mold holding unit.   Based on the observation image of the pattern surface of the mold by the observation unit, it is determined whether or not the mold needs to be cleaned, and when it is determined that the cleaning is necessary, The pattern transfer apparatus according to claim 4, further comprising a cleaning control unit that controls the relative movement of the mold holding unit and the cleaning unit cleaning the mold held by the mold holding unit. . A heating unit for heating the mold held by the mold holding unit;
By pressing the mold heated by the heating unit against the processing target object held by the target object holding part by the moving mechanism, the processing target object is heated to near or above the glass transition temperature, The pattern transfer apparatus according to claim 1, wherein the pattern formed on the mold is transferred to the object to be processed. An excitation mechanism for applying vibration to the mold or the object holding part held by the mold holding part;
When the mold and the object to be processed are separated from each other after the mold held by the mold holding part is pressed against the object to be processed held by the object holding part, the mold or the object holding part A control unit that controls the excitation mechanism to apply vibration;
The pattern transfer apparatus according to claim 1, further comprising: A mold for forming a predetermined pattern on the workpiece;
An object holding unit for holding the object to be processed;
An excitation mechanism for applying vibration to the mold or the object holding unit;
A heating section for heating the mold;
A moving mechanism for relatively moving the mold and the object holding unit in at least two directions;
A cleaning unit that is provided within a moving range of the mold by the moving mechanism and that cleans at least a pattern surface of the mold;
With
The mold heated by the heating unit is moved relative to the object to be processed by the moving mechanism and pressed against the object to be processed, so that the object to be processed is heated near or above the glass transition temperature. A pattern transfer apparatus for forming a predetermined pattern on the workpiece with the mold. In a pattern transfer apparatus for transferring a pattern formed on a mold to a workpiece, a method for cleaning the pattern surface of the mold,
Moving the mold to a position facing a cleaning tank provided in the range within a range in which the mold can move relative to the workpiece;
Immersing at least the pattern surface of the mold in a cleaning liquid in the cleaning tank;
Applying ultrasonic vibration to the cleaning liquid or the mold, and ultrasonically cleaning the pattern surface of the mold with the cleaning liquid;
A mold cleaning method comprising: Observing the pattern surface of the mold at a predetermined timing, further comprising determining whether or not the mold needs to be washed based on the observation result;
The mold according to claim 9, wherein when it is determined in the determining step that cleaning is necessary, the mold and the cleaning tank are relatively moved, and the mold is cleaned in the cleaning tank. Cleaning method. A pattern transfer method for transferring a predetermined pattern onto a substrate with a mold,
Heating the mold to a predetermined temperature based on the glass transition temperature of the substrate;
A pattern transfer step of transferring the pattern by pressing the mold against the substrate;
Observing the pattern surface of the mold at a predetermined timing, and determining whether the mold needs to be cleaned based on the observation result;
When it is determined that the cleaning is necessary in the determining step, the step of cleaning the mold in a cleaning tank provided in a range in which the mold can be moved relative to the workpiece;
A pattern transfer method comprising:

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