JP2012059956A - Resist pattern forming method and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide resist pattern forming method and a device for the same, which can improve the protection performance of a first resist pattern and the in-plane coating performance of a second resist while saving the resist.SOLUTION: In the resist pattern formation in which a lithography process of performing lithography processing such as resist coating, exposure, development and the like on a wafer to form a predetermined pattern is repeated, a resist containing a cross-linking agent is applied (S-1) to the wafer, and then exposed (S-4) and developed (S-6) to form a first resist pattern. After irradiating (S-7) the first resist pattern with UV-rays for a predetermined time and heating (S-8) the wafer on which the first resist pattern is formed at a predetermined temperature, a second resist is applied (S-9) to the wafer on which the first resist pattern is formed, exposed (S-12) and developed (S-14) to form a second resist pattern.

Description

  The present invention relates to a resist pattern forming method and apparatus for performing a lithography process on a substrate such as a semiconductor wafer or a glass substrate for LCD.

  In general, in the manufacture of semiconductor devices, a photolithography technique is used to form an ITO (Indium Tin Oxide) thin film or an electrode pattern on a substrate such as a semiconductor wafer or an LCD glass substrate. In this photolithography technique, a photoresist (hereinafter referred to as a resist) is applied to a substrate, a resist film formed thereby is exposed in accordance with a predetermined circuit pattern, and the exposure pattern is developed to form a resist film. In this process, a desired circuit pattern is formed by a series of lithography processes.

  Incidentally, in recent years, there has been an increasing demand for miniaturization of device patterns, and as one of the miniaturization methods, a double patterning technique is known in which a resist pattern is formed by using a lithography process a plurality of times.

  In this type of double patterning technology, a resist processing method using a resist containing a cross-linking agent is known for the purpose of protecting the first pattern resist formed in the first lithography process from the second lithography process. (For example, refer to Patent Document 1).

  In a so-called self-crosslinking process technique using a resist containing a crosslinking agent, dissolution resistance can be imparted by heating (hard baking) the substrate on which the first pattern is formed by the first lithography step.

JP 2010-28101 A

  However, the self-crosslinking process technology is intended to protect the dissolution and mixing of the first resist pattern from the resist in the second lithography process, but depending on the compatibility of the resist in the first and second lithography processes or the heat treatment temperature limit. Can not protect enough. That is, there is a problem that the first resist pattern is dissolved and broken, and the second resist pattern cannot be normally coated, that is, the uniformity of in-plane application of the resist is lowered.

  As a technique for solving this problem, it is conceivable to promote the crosslinking reaction by high-temperature heat treatment in order to make it difficult to dissolve the first resist pattern from the resist in the second lithography process. However, the heat treatment at a high temperature causes deformation and alteration of the first resist pattern, and lowers the lithography performance.

  In the self-crosslinking process technology, the resist is applied without using a solvent in order to prevent the first resist pattern from being dissolved by the pre-wet solvent used in the second resist coating process in the second lithography process. There is a need to. For this reason, a large amount of resist is used, and an expensive resist solution is wasted.

  The present invention has been made in view of the above circumstances, and is a resist capable of improving the protection performance of the first resist pattern and improving the in-plane coating performance of the second resist and reducing the amount of chemicals used in the resist. A pattern forming method and an apparatus thereof are provided.

  In order to solve the above-mentioned problems, the invention described in claim 1 is a resist pattern forming method for repeatedly performing a lithography process for forming a predetermined pattern by performing lithography processing such as resist coating processing, exposure processing and development processing on a substrate. And applying a resist containing a cross-linking agent to the substrate, then exposing and developing to form a first resist pattern, and applying ultraviolet light to the first resist pattern after the first pattern forming step. UV irradiation step for irradiating the substrate for a predetermined time; heating step for heating the substrate on which the first resist pattern is formed at a predetermined temperature; applying a second resist to the substrate on which the first resist pattern is formed; And developing a second resist pattern to form a second resist pattern.

  By comprising in this way, the molecular chain of a resist composition is cut | disconnected, for example by irradiating a 1st resist pattern formed by apply | coating the resist containing a crosslinking agent to a board | substrate, exposing and developing. . This facilitates the reaction (bonding) of the cross-linking agent, and by heating the substrate on which the first resist pattern is formed, the first resist can have resistance to dissolution with respect to the second resist, and the contact angle. Can be reduced.

  In the present invention, the ultraviolet irradiation time in the ultraviolet irradiation step is preferably set to 2.1 to 5 seconds, for example.

  In the present invention, the ultraviolet irradiation step may be carried out in the atmosphere, but is preferably carried out by supplying oxygen gas or inert gas (for example, nitrogen gas) into the processing space partitioned from the outside. Better.

  With this configuration, generation of ozone (O3) gas generated by ultraviolet irradiation can be suppressed, and reduction of resist due to ozone (O3) gas can be suppressed.

  In the present invention, the heating temperature in the heating step is preferably lower than the glass transition temperature. For example, the heating temperature is preferably lower than the glass transition temperature and higher than 190 ° C.

  Moreover, in this invention, it is preferable to perform the said heating process immediately after the said ultraviolet irradiation process, More preferably, it is better to perform the said ultraviolet irradiation process and the said heating process simultaneously.

  The invention according to claim 8 is a resist pattern forming apparatus for repeatedly performing a lithography process for forming a predetermined pattern by performing a lithography process such as a resist coating process, an exposure process and a developing process on a substrate, and a cross-linking agent is applied to the substrate. A pattern forming unit including a coating processing unit that applies a resist containing, an exposure processing unit that exposes a substrate coated with the resist, a development processing unit that develops the exposed substrate, and the like. An ultraviolet irradiation device that irradiates the substrate after development processing on which the resist pattern is formed; and a heating unit that heats the substrate after development processing on which the first resist pattern is formed by the pattern formation unit, It is characterized by that.

  By comprising in this way, after forming the 1st resist pattern by apply | coating the resist containing a crosslinking agent to a board | substrate by a pattern formation part, exposing and developing, and irradiating an ultraviolet-ray to a 1st resist pattern, it bridge | crosslinks. By making the reaction (bonding) of the agent easy, and heating the substrate on which the first resist pattern is formed in the heating unit, the first resist can be resistant to dissolution with respect to the second resist, and the contact angle Can be reduced.

  In this invention, the substrate after the development processing on which the first resist pattern is formed by the pattern forming unit is transported to the ultraviolet irradiation device, and the substrate heated by the heating unit is transferred to the resist processing unit of the pattern forming unit. It is preferable to further include a main transport mechanism for transporting and an auxiliary transport mechanism for transporting the substrate irradiated with ultraviolet rays by the ultraviolet irradiation device to the heating unit.

  Also, in the present invention, the ultraviolet irradiation device includes a substrate holder that holds the surface of the substrate as an upper surface, an ultraviolet irradiator that irradiates the substrate held on the substrate holder with ultraviolet rays, and the substrate holder. It is better to have a moving mechanism that relatively translates the ultraviolet irradiation body. In this case, it is preferable that the substrate holder and the moving mechanism constitute the auxiliary transport mechanism that transports the substrate irradiated with ultraviolet rays by the ultraviolet irradiation device to the heating unit.

  In the present invention, the substrate holder, the ultraviolet irradiator, and the heating unit are disposed in the housing, and are formed so that oxygen gas or inert gas (for example, nitrogen gas) can be supplied into the processing space in the housing. Better to do.

  With this configuration, generation of ozone (O3) gas generated by ultraviolet irradiation can be suppressed, and reduction of resist due to ozone (O3) gas can be suppressed.

  Moreover, in this invention, you may arrange | position the heating body which comprises the said heating part in the said board | substrate holding stand. By comprising in this way, the ultraviolet irradiation and heat processing with respect to the board | substrate with which the 1st resist pattern was formed can be performed simultaneously.

  Moreover, in this invention, it is better to set the ultraviolet irradiation time in the said ultraviolet irradiation apparatus to 2.1 to 5 second, for example.

  In addition, in the present invention, the heating temperature in the heating section is preferably set to be equal to or lower than the glass transition temperature. For example, the heating temperature is preferably set to be equal to or lower than the glass transition temperature and higher than 190 ° C.

  According to the present invention, the first resist pattern can have resistance to dissolution of the first resist with respect to the second resist, and the contact angle can be reduced, so that the protection performance of the first resist pattern can be improved and The in-plane coating performance of the second resist can be improved, and the resist can be saved.

1 is a schematic plan view showing an example of a resist coating / development processing apparatus to which a resist pattern forming apparatus according to the present invention is applied. It is a schematic perspective view of the said resist application | coating / development processing apparatus. It is a schematic sectional drawing of the said resist application | coating / development processing apparatus. It is the schematic plane sectional view (a) and schematic sectional drawing (b) which show the coating unit in the said resist coating / development processing apparatus. It is a schematic perspective view which shows the unit block (DEV layer) of the processing block in the said resist application | coating / development processing apparatus. It is principal part sectional drawing which shows 1st Embodiment of the resist pattern formation apparatus concerning this invention. It is principal part plane sectional drawing of the said resist pattern formation apparatus. It is a flowchart which shows the process process of the pattern formation method of 1st Embodiment. It is principal part sectional drawing which shows 2nd Embodiment of the resist pattern formation apparatus which concerns on this invention. It is a flowchart which shows the process process of the pattern formation method of 2nd Embodiment. It is a graph which shows the relationship between the presence or absence of the ultraviolet irradiation obtained from the evaluation experiment of the resist pattern formation method concerning this invention, and resist solubility. It is a graph which shows the relationship between the presence or absence of the ultraviolet irradiation obtained from another evaluation experiment of the resist pattern formation method concerning this invention, and resist solubility.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, a case where the resist pattern forming apparatus according to the present invention is applied to a resist coating / development processing system will be described.

  The resist coating / development processing system includes a carrier block S1 that is a loading / unloading unit for loading / unloading, for example, 25 carriers 10 in which a semiconductor wafer W (hereinafter referred to as a wafer W), which is a substrate to be processed, is hermetically contained. A coating / development processing unit block S2 (hereinafter referred to as processing block S2) that is a coating / development processing unit configured by vertically arranging a plurality of unit blocks B1 to B4, for example, and an interface block that is an interface unit S3 and exposure apparatus S4 which is an exposure process part are comprised. In this resist coating / development processing system, a resist pattern forming section is formed by the processing block S2, the interface block S3, and the exposure apparatus S4.

  As shown in FIG. 2, the processing block S2 is a first block (DEV layer) B1 for performing a developing process and an antireflection film forming process formed on the lower layer side of the resist film in this example. The second block (BCT layer) B2, the third block (COT layer) B3 for applying the resist film, and the fourth block for forming the antireflection film formed on the upper layer side of the resist film Blocks (TCT layers) B4 are stacked in order from the bottom.

  Further, in the processing block S2, thermal system shelf unit groups U1 to U4 in which a heating unit and a cooling unit for heating and cooling the wafer after resist coating or development are respectively stacked are arranged. Moreover, the ultraviolet irradiation apparatus 50 mentioned later is arranged in parallel with thermal system shelf unit group U1-U4 in process block S2.

  The second block (BCT layer) B2 and the fourth block (TCT layer) B4 are respectively applied by applying units 22 and 24 for applying a chemical solution for forming an antireflection film by spin coating, A heating / cooling system processing unit group for performing pre-processing and post-processing of the processing to be performed, and a main transfer mechanism that is provided between the coating unit and the processing unit group and transfers the wafer W between them. And transfer arms A2 and A4.

  The third block (COT layer) B3 has the same configuration except that the chemical solution is a first resist solution or a second resist solution containing a crosslinking agent. That is, a coating unit 23 that is a coating processing unit that applies a first resist solution containing a crosslinking agent by spin coating, and a heating / cooling system for performing pre-processing and post-processing of the processing performed in the coating unit 23 And a transfer arm A3 which is provided between the coating unit and the processing unit group and serves as a main transfer mechanism for transferring the wafer W between them.

  As shown in FIG. 4, the coating units 23 are arranged in a row in a horizontal direction (Y direction in the figure) in a flat box-shaped housing 30 having a loading / unloading port 30a for a wafer W on one side wall. And three liquid processing units 23a, 23b, and 23c, and a plurality of liquid processing units 23a, 23b, and 23c that supply a coating solution such as a first resist solution, a second resist solution, and a thinner containing a crosslinking agent. A nozzle 31, a nozzle transport mechanism 32 for transporting the nozzle 31, a nozzle bus 33 for waiting the nozzle 31, and an edge bead remover (Edge) for removing the peripheral portion of the resist film applied to the wafer W Bead Remover (EBR) mechanism 34.

  In this case, the liquid processing units 23a, 23b, and 23c have a common configuration, and a spin chuck 35 serving as a substrate holding unit and a cup body 36 that is held by the spin chuck 35 and is disposed so as to surround the wafer W. And.

  In addition, the nozzle transport mechanism 32 moves the base 12 on the rail 13, the nozzle arm 32 a that holds the nozzle 31, the base 32 b that supports the nozzle arm 32 a, the guide rail 32 c that forms the travel path of the base 32 b, and the rail 13. It is comprised from the mechanism to make.

  According to the coating unit 23 configured as described above, the wafer W loaded into the housing 30 from any one of the three loading / unloading ports 30a by the external transfer arm A3 is loaded / unloaded 30a. Are transferred to the spin chuck 35 of the liquid processing units 23a, 23b, and 23c.

  And the nozzle conveyance mechanism 32 is operated, the nozzle arm 32a made to stand by on the nozzle bus 33 is lifted, and it conveys in the Y direction of FIG. Next, when the nozzle 31 for supplying thinner reaches a position substantially above the center of the wafer W, the movement of the nozzle arm 32a is stopped, and the nozzle arm 11 is lowered at that position. Then, after supplying thinner from the nozzle 31 onto the stationary wafer W, the supply nozzle 31 of the first resist solution containing the crosslinking agent to be applied in the process is positioned substantially above the center of the wafer W. The nozzle arm 32a is moved. In parallel with this moving operation, the spin chuck 35 is rotated at a high speed, for example, and the first resist solution is supplied onto the rotating wafer W, stopped and spread in the radial direction of the wafer W.

  Subsequently, the spin chuck 35 is rotated at a low speed, the film pressure of the spin-coated first resist film is made uniform, and then the coated first resist solution is shaken and dried by rotating again at a high speed. During this time, the nozzle transport mechanism 32 moves the nozzle arm 32 a along a path opposite to the above-described path, and causes the nozzle 31 that has completed the supply of the coating liquid to wait on the nozzle bus 14.

  On the other hand, the corresponding EBR mechanism 6 is operated for the wafer W that has been shaken and dried, and the rinse liquid nozzle is transferred from the EBR nozzle bus 33 to the peripheral edge of the wafer W, where the rinse liquid is applied, and spin After the first resist film applied to the peripheral edge of the wafer W is removed by rotating the chuck 35, the rinse liquid is shaken and dried in the same manner as in the case of the resist film to complete a series of resist coating processes.

  The above operation is the case of the resist coating process for forming the first resist pattern. However, when forming the second resist pattern, the second resist solution is supplied without supplying the thinner, and the same operation as described above is performed. To complete a series of resist coating processes.

  On the other hand, with respect to the first block (DEV layer) B1, as shown in FIG. 3, development units 21 as development processing units are stacked in two stages in one DEV layer B1. In the DEV layer B1, a transfer arm A1, which is a main transfer mechanism for transferring the wafer W to the two-stage developing unit 21, is provided. That is, the transport arm A1, which is a transport mechanism, is shared by the two-stage development unit.

  The thermal shelf units U1 to U4 in the first block (DEV layer) B1 include, for example, a heating unit called a post-exposure baking unit that heats the exposed wafer W as shown in FIG. PEB1), a heating unit (POST1) referred to as a post-baking unit or the like for performing heat treatment to remove moisture of the wafer W after development processing, and the like are included. Each processing unit such as these heating units (PEB1, POST1) is accommodated in a processing container 91, and the thermal shelf units U1 to U4 are configured by stacking the processing containers 91 in three stages. A wafer loading / unloading port 92 is formed on the surface of the processing container 91 facing the transfer region R1.

  The transfer arm A1 is provided in the transfer region R1 of the first block (DEV layer) B1. This transfer arm A1 is a wafer between all the modules in the DEV layer B1 (where the wafer W is placed), for example, each processing unit of the thermal shelf units U1 to U4, the developing unit 21, and each part of the shelf unit U5. It is configured to deliver W, and for this purpose, it is configured to be movable in the horizontal X and Y directions and the vertical Z direction and to be rotatable about the vertical axis.

  For example, the transfer arm A1 (A3 to A5) is configured similarly, and as shown in FIG. 5, a two-stage substantially horseshoe shape having a plurality of holding claws 41 projecting at appropriate positions on the inner peripheral wall side. Arm main body 40, a holding base 42 for holding each arm main body 40 movably in the horizontal direction, a rotation drive mechanism 43 for supporting the holding base 42 rotatably in the horizontal direction, a horizontal guide rail 44 and a vertical guide rail. 45 is configured to be movable forward and backward in the X direction, movable in the Y direction, freely movable up and down, and rotatable about the vertical axis by the moving mechanism 46 for moving along the 45. Each unit of the thermal system shelf units U1 to U6 and delivery The wafer W can be transferred between the stage TRS1, the liquid processing unit, and the ultraviolet irradiation device pattern forming unit.

  Further, the processing block S2 is provided with a shelf unit U5 as shown in FIGS. 1 and 2, and the wafer W taken out from the carrier 10 of the carrier block S1 by the delivery arm C is one delivery unit of the shelf unit U5, For example, it is configured to be sequentially transported to the corresponding delivery unit CPL2 of the second block (BCT layer) B2 by the first delivery arm D which is a main transport mechanism that is movable up and down provided in the vicinity of the shelf unit U5. ing.

  On the other hand, on the upper part in the DEV layer B1, a shuttle arm E, which is a dedicated transfer means for directly transferring the wafer W from the transfer unit CPL11 provided in the shelf unit U5 to the transfer unit CPL12 provided in the shelf unit U6. Is provided. The wafer W on which the resist film and further the antireflection film are formed is transferred from the transfer units BF3 and TRS4 to the transfer unit CPL11 via the transfer arm D, and from there to the transfer unit CPL12 of the shelf unit U6 by the shuttle arm E. It is directly conveyed and taken into the interface block S3. The wafer W transferred to the transfer unit CPL11 is transferred to the exposure apparatus S4 by the transfer arm F. Note that the delivery unit with CPL in FIG. 3 also serves as a cooling unit for temperature control, and the delivery unit with BF also serves as a buffer unit on which a plurality of wafers W can be placed. .

  The transport mechanisms such as the transport arms A1 to A4, the delivery arms C, D, and F, and the shuttle arm E, the drive mechanism for the coating unit and the developing unit, and the like are electrically connected to the control unit 100 that is a control unit. The control unit 100 is configured to be controlled based on a program stored in advance.

  The basic processing flow of the resist coating / development processing system configured as described above is performed by the following steps. That is, first, the wafer W taken out by the transfer arm C from the carrier 10 of the carrier block S1 is transferred to the transfer unit CPL2 of the shelf unit U5. Next, the transfer arm A2 in the second block (BCT layer) B2 receives the wafer W from the transfer unit CPL2 and transfers it to each unit (antireflection film unit and heating / cooling system processing unit group). In these units, an antireflection film is formed on the wafer W.

  Thereafter, the wafer W is transferred into the third block (COT layer) B3 via the transfer unit BF2, the transfer arm D, the transfer unit CPL3 of the shelf unit U5, and the transfer arm A3, and contains the cross-linking agent. One resist solution is applied to form a first resist film. Further, the wafer W is transferred to the transfer unit BF3 in the shelf unit U5 via the transfer arm A3, the transfer unit BF3 of the shelf unit U5, and the transfer arm D. Thereafter, the wafer W is transferred to the transfer unit CPL11 by the transfer arm D and transferred to the transfer unit CPL12 of the shelf unit U6 by the shuttle arm E.

  Next, the wafer W is transferred to the exposure apparatus S4 by the interface arm F, and after performing a predetermined exposure process, it is placed on the transfer unit TRS6 of the shelf unit U6 and returned to the processing block S2. The returned wafer W is developed in the first block (DEV layer) B1, and a first resist pattern is formed on the surface of the wafer W. The wafer W on which the first resist pattern is formed is transferred to the transfer table TRS1 of the shelf unit U5 by the transfer arm A1. After that, the transfer arm D carries it again into the third block (COT layer) B3 via the transfer unit CPL3 and the transfer arm A3, and the second resist solution is supplied to form the second resist film. On the wafer W on which the second resist film is formed, a second resist pattern is formed through the same processes as described above, that is, the exposure process and the development process. The wafer W on which the second resist pattern is formed is transferred to the transfer table TRS1 of the shelf unit U5 by the transfer arm A1. After that, the first transfer arm D is transported to the transfer table in the access range of the transfer arm C in the shelf unit U5 and is returned to the carrier 10 via the transfer arm C.

  Next, the ultraviolet irradiation apparatus 50 and the heating part 60 in this invention are demonstrated. The ultraviolet irradiation device 50 includes a substrate holder 51 that holds the surface of the wafer W as an upper surface, an ultraviolet lamp 52 that is an ultraviolet irradiation body that irradiates the wafer W held on the substrate holder 51 with ultraviolet rays, and a substrate holder. 51 and a moving mechanism that relatively translates the ultraviolet lamp 52, for example, a ball screw mechanism 53 is provided.

  For example, as shown in FIGS. 6 and 7, the ultraviolet irradiation device 50 has an ultraviolet lamp 52 horizontally provided at the center upper portion in a flat box-shaped housing 54 having a loading / unloading port 54 a on the side to hold the substrate. A base 51 is mounted on a screw shaft 53a of a ball screw mechanism 53 via a support member 55 connected to the lower side of the substrate holding base 51, and one side portion of the housing 54 is rotated by forward and reverse rotation of a drive motor 53b. It is configured to be able to reciprocate in the horizontal direction perpendicular to the ultraviolet lamp 52 from the loading / unloading port 54a side toward the other side portion. In this case, the ultraviolet lamp 52 is formed of a straight ultraviolet irradiation lamp having a length equal to or larger than the diameter of the wafer W and having a wavelength of 172 nm.

  A shutter 56 that opens and closes the loading / unloading port 54a by an opening / closing mechanism (not shown) is provided outside the loading / unloading port 54a of the housing 54. Further, as shown in FIG. 6, the substrate holding base 51 is formed in a fork shape provided with two guide grooves 51 a that open at the front end side. A transfer body 57 having three support pins 57a penetrating the guide grooves 51a of the substrate holding table 51 is disposed below the substrate holding table 51 in the standby position (right side in FIG. 7). The transfer body 57 is formed so as to be movable up and down by an elevating mechanism (not shown) so that the wafer W is transferred to and from the transfer arm A1 entering the housing 54 via the loading / unloading port 54a. It has become.

  Further, a heating unit 60 for heating the wafer W irradiated with ultraviolet rays by the ultraviolet lamp 52 is disposed in the housing 54 on the opposite side of the ultraviolet lamp 52 to the loading / unloading port 54a side. The heating unit 60 includes a hot plate 62 in which a heater 61 on which the wafer W is placed is built in, a cover 64 that can be moved up and down above the hot plate 62 by driving a cover lifting cylinder 63, and a hot plate Three transfer pins 65 that can be moved up and down and pass through through holes (not shown) provided in 62 are provided. The delivery pin 65 is erected on the support plate 66, and the delivery pin 65 can be projected and retracted above the surface of the heat plate 62 by driving the pin lift cylinder 67 via the lift rod 67 a connected to the support plate 66. Has been. That is, the pin lifting cylinder 67 is driven and the delivery pin 65 in a state where the substrate holding base 51 on which the wafer W is placed is transported above the hot plate 62 by driving the ball screw mechanism 53 that also serves as an auxiliary transport mechanism. Rises to receive the wafer W from the substrate holder 51, and then descends to place the wafer W on the hot plate 62. After the heat treatment of the wafer W, conversely, the wafer W on the hot plate 62 is moved to the hot plate. It is configured to move above 62 and transfer it to the substrate holder 51.

  Further, a gas supply port 71 is provided in the ceiling portion of the casing 54, and a gas supply means, for example, an oxygen gas cylinder 70 is connected through a gas supply pipe 72 connected to the gas supply port 71. Oxygen (O 2) gas is supplied from the oxygen gas cylinder 70 into the housing 54 by opening the on-off valve 73 interposed in the supply pipe 72. The gas supply means may be replaced with a nitrogen gas cylinder instead of the oxygen gas cylinder 70 to supply nitrogen (N 2) gas into the housing 54.

  By supplying oxygen (O 2) gas or nitrogen (N 2) gas into the housing 54 in this way, the inside of the housing 54 can be brought into an oxygen (O 2) gas or nitrogen (N 2) gas atmosphere, and an ultraviolet lamp The generation of ozone (O3) gas generated by the irradiation of ultraviolet rays 52 can be suppressed, and the decrease in resist caused by the ozone (O3) gas can be suppressed.

  The ultraviolet lamp 52, the ball screw mechanism 53, the heater 61 of the heating unit 60, the cover elevating cylinder 63, the pin elevating cylinder 67, and the on-off valve 73 are electrically connected to a controller 80 as control means. The operation is based on a control signal from the controller 80. For example, based on a control signal from the controller 80, the ultraviolet lamp 52 is irradiated for 2.1 to 5 seconds, and the heater 61 is set to an optimum temperature condition necessary for the crosslinking reaction by each resist.

  In the above embodiment, the ball screw mechanism 53 serving as both a moving mechanism and a conveying mechanism has been described. However, a mechanism other than the ball screw mechanism 53 such as a belt driving mechanism and a linear motor driving mechanism constitutes the moving mechanism and the conveying mechanism. May be.

  In addition, although the said embodiment demonstrated the case where the ultraviolet irradiation device 50 was provided separately from heat system shelf unit U1-U4, it is also possible to provide by incorporating in a part of heat system shelf unit U1-U4. Thus, by incorporating the ultraviolet irradiation device 50 into the heat system shelf units U1 to U4, the size of the device can be reduced.

  Next, the operation mode of the resist pattern forming apparatus configured as described above will be described with reference to the flowchart shown in FIG.

<First resist pattern forming step>
A first resist solution containing a crosslinking agent is applied to the wafer W carried into the third block (COT layer) B3 to form a resist film on the surface of the wafer W (S-1). The wafer W on which the resist film is formed is transferred to the thermal shelf unit, and the residual solvent is evaporated and removed from the resist film by pre-bake processing (S-2). After cooling processing (S-3), the wafer W is transferred to the exposure apparatus S4. Then, after the exposure process (S-4), the post-exposure baking process (S-5) is performed to make the positive resist soluble in the developer. Thereafter, the wafer W is carried into the first block (DEV layer) B1 and developed (S-6), and a first resist pattern is formed on the surface of the wafer W.

  The wafer W on which the first resist pattern is formed is taken out from the first block (DEV layer) B1 by the transfer arm A1, loaded into the ultraviolet irradiation device 50, and placed on the substrate holding table 51. Next, the driving motor pattern forming unit of the moving mechanism / auxiliary transfer mechanism, for example, the ball screw mechanism 53 is driven to horizontally move the substrate holder 51 in the left direction in FIG. (S-7). At this time, the wavelength of the ultraviolet rays irradiated from the ultraviolet lamp 52 is 172 nm, and the irradiation time is set to 2.1 to 5 seconds, for example.

  By irradiating ultraviolet rays onto the surface of the wafer W on which the first resist pattern is formed in this way, it is possible to facilitate the reaction (bonding) of the crosslinking agent.

  The wafer W irradiated with ultraviolet rays is continuously conveyed above the hot plate 62 of the heating unit 60, placed on the hot plate 62, and heated to a temperature optimal for the crosslinking reaction (below the glass transition temperature). (S-8). Thereby, the 1st resist containing a crosslinking agent can be given the melt | dissolution tolerance with respect to subsequent 2nd resist, and a contact angle can be reduced.

<Second resist pattern forming step>
The wafer W on which the first resist pattern subjected to the ultraviolet irradiation and the heat treatment (hard baking process) is formed is unloaded from the housing 54 of the ultraviolet irradiation apparatus 50 by the transfer arm A1, and then transferred to the transfer table TRS1 for transfer. The arm D is transferred again to the third block (COT layer) B3 via the transfer unit CPL3 and the transfer arm A3, and the second resist solution is applied to the surface of the first resist pattern on the surface of the wafer W, and the second resist film. Is formed (S-9). In this second resist coating process, since the contact angle is reduced, that is, hydrophilic, by irradiating the surface of the wafer W on which the first resist pattern has been formed as described above with the application of the second resist solution. In this case, the second resist solution can be applied without using a thinner (solvent).

  The wafer W on which the second resist film is formed is subjected to a pre-bake process (S-10) and a cooling process (S-11), then transferred to the exposure apparatus S4, subjected to an exposure process (S-12), and then post-processed. The exposure baking process (S-13) is performed to make the positive resist soluble in the developer. Thereafter, the wafer W is carried into the first block (DEV layer) B1 and developed (S-14), and a second resist pattern is formed on the surface of the wafer W. The wafer W on which the second resist pattern is formed is transferred to the thermal shelf unit, subjected to post-baking (S-15) and cooling (S-16), and then delivered to the shelf unit U5 by the transfer arm A1. Passed to the table TRS1. After that, the first transfer arm D is transported to the transfer table in the access range of the transfer arm C in the shelf unit U5 and is returned to the carrier 10 via the transfer arm C.

  In the above-described embodiment, the case where the heating unit 60 heats the wafer W after irradiating the first resist film of the wafer W on which the first resist pattern is formed has been described. However, the wafer W is heated simultaneously with the ultraviolet irradiation. May be.

  For example, as shown in FIG. 9, a heater 61A is built in a substrate holding table 51A that can be reciprocated in a horizontal direction orthogonal to the ultraviolet lamp 52 by a moving mechanism such as a ball screw mechanism 53, and a heating unit is provided on the substrate holding table 51A. It may be used also. The embodiment shown in FIG. 8 is the same except that the heating unit 60 of the first embodiment is omitted. Therefore, the same parts are denoted by the same reference numerals and the description thereof is omitted.

  With this configuration, the wafer W on which the first resist pattern held by the substrate holder 51 is formed is formed on the surface of the wafer W in a state where the wafer W is heated to a predetermined temperature, for example, 190 ° C. below the glass transition temperature. The first resist pattern can be irradiated with ultraviolet rays. Therefore, the apparatus can be reduced in size and the throughput can be improved.

  Next, the operation | movement aspect of the resist pattern formation apparatus of 2nd Embodiment comprised as mentioned above is demonstrated with reference to the flowchart shown in FIG. Here, the same parts as those of the operation mode of the resist pattern forming apparatus of the first embodiment will be omitted and described.

<First resist pattern forming step>
A first resist solution containing a cross-linking agent is applied to the wafer W carried into the third block (COT layer) B3 to form a first resist film on the surface of the wafer W (S-1). The wafer W on which the first resist film is formed is pre-baked (S-2) → cooling (S-3) → exposure (S-4) → post-exposure baking (S-5) → development (S -6), and the first resist pattern is formed on the surface of the wafer W.

  The wafer W on which the first resist pattern is formed is taken out from the first block (DEV layer) B1 by the transfer arm A1, loaded into the ultraviolet irradiation device 50A, placed on the substrate holding table 51A, and heated by the heater 61A. It is heated to a predetermined temperature, for example 190 ° C. Next, the drive motor pattern forming unit of the ball screw mechanism 53 is driven to horizontally move the substrate holder 51A in the left direction in FIG. 9 and irradiate the surface of the wafer W with ultraviolet rays from the ultraviolet lamp 52 {S-7. (S-8)}. At this time, the wavelength of the ultraviolet rays irradiated from the ultraviolet lamp 52 is 172 nm, and the irradiation time is set to 2.1 to 5 seconds, for example.

  By heating the wafer W on which the first resist pattern is formed in this manner and simultaneously irradiating the wafer surface with ultraviolet rays, it is possible to facilitate the reaction (bonding) of the crosslinking agent and to contain the crosslinking agent. The first resist can have resistance to subsequent dissolution of the second resist, and the contact angle can be reduced.

<Second resist pattern forming step>
The wafer W on which the first resist pattern that has been subjected to ultraviolet irradiation and heat treatment (hard baking process) is formed is unloaded from the housing 54 of the ultraviolet irradiation apparatus 50A by the transfer arm A1, and then transferred to the transfer table TRS1 for transfer. The arm D is transferred again to the third block (COT layer) B3 via the transfer unit CPL3 and the transfer arm A3, and the second resist solution is applied to the surface of the first resist pattern on the surface of the wafer W, and the second resist film. Is formed (S-9). In this second resist coating process, since the contact angle is reduced, that is, hydrophilic, by irradiating the surface of the wafer W on which the first resist pattern has been formed as described above with the application of the second resist solution. In this case, the second resist solution can be applied without using a thinner (solvent).

  The wafer W on which the second resist film is formed is pre-baked (S-10) → cooling (S-11) → exposure (S-12) → post-exposure baking (S-13) → development (S -14) → Post bake process (S-15) → Cooling process (S-16). Thereafter, the sheet is transferred to the transfer table TRS1 of the shelf unit U5 by the transfer arm A1. After that, the first transfer arm D is transported to the transfer table in the access range of the transfer arm C in the shelf unit U5 and is returned to the carrier 10 via the transfer arm C.

  According to the resist pattern forming method (apparatus) of the above embodiment, the first resist pattern is irradiated with ultraviolet rays to facilitate the reaction (bonding) of the crosslinking agent, and the substrate on which the first resist pattern is formed is heated. As a result, the first resist can be resistant to dissolution with respect to the second resist, and the contact angle can be reduced, that is, the affinity can be increased. Therefore, even in the case of a self-crosslinking resist used for immersion exposure, it is applicable because the reaction (bonding) of the crosslinking agent can be facilitated by irradiating the first resist pattern with ultraviolet rays.

  According to the resist pattern forming method of the present invention, in addition to the line-type double pattern shape for forming the line-shaped second resist pattern between the line-shaped first resist patterns, the line-shaped first resist After the pattern is formed, it is possible to form a hole type pattern that forms the second resist pattern by rotating the wafer W by 90 degrees in the horizontal direction.

  Next, an evaluation experiment for examining the effect of the resist pattern forming method according to the present invention will be described with reference to FIGS.

<Evaluation Experiment 1>
Experimental conditions / resist: self-crosslinking resist containing a crosslinking agent / UV wavelength: 172 nm
・ Environment: Air Sample ・ Comparative Example 1: No ultraviolet (UV) irradiation, hard baking time 190 seconds ・ Comparative Example 2: Ultraviolet (UV) irradiation time 2.1 seconds, no hard baking ・ Example 1: Ultraviolet (UV) ) Irradiation time 2.1 seconds, hard bake time 190 seconds. Example 2: ultraviolet (UV) irradiation time 5.0 seconds, hard bake time 190 seconds. Example 3: ultraviolet (UV) irradiation time 10.0 seconds. Hard baking time 190 seconds Under the above conditions, an evaluation experiment was conducted to examine the resist solubility. As a result, the results shown in Table 1 and FIG. 10 were obtained.

  As shown in Table 1 and FIG. 11, in Comparative Example 1 without UV irradiation, the film thickness variation was 15.77 nm, and in Comparative Example 2 without hard baking, the film thickness variation was 27.63 nm. there were. On the other hand, in Example 1 (UV irradiation 2.1 seconds, hard baking time 190 seconds) and Example 2 (UV irradiation 5.0 seconds, hard baking time 190 seconds), the film thickness variation was 0. In Example 3 (UV irradiation 10.0 seconds, hard baking time 190 seconds), the film thickness variation was 0.32 nm in both cases.

  As a result of the evaluation experiment 1, it was found that by adding a UV irradiation process to the conventional hard baking process, the film thickness reduction at the center of the wafer was remarkably reduced and the solubility of the resist was improved. Further, as apparent from the evaluation experiment, the influence of the difference in UV irradiation time is small, and the UV irradiation time is 2. It was found that ~ 5.0 seconds was sufficient.

<Evaluation Experiment 2>
A resist pattern was formed on the wafer, and the experiment was performed under the same conditions as in the above evaluation experiment 1. Comparative Example 3 (no UV irradiation, hard baking time 190 seconds) and Example 4 (UV irradiation time 2.1 seconds, hard When the film thickness variation at the wafer central portion during the baking time (190 seconds) was examined, the result shown in FIG. 12 was obtained.

  As a result of the above evaluation experiment 2, it was found that by adding a UV irradiation process to the hard bake treatment of the prior art, it is possible to coat without application spots (application unevenness).

S2 processing block (coating / development processing section lock)
S3 Interface block S4 Exposure apparatus (exposure processing section)
B1 DEV layer B3 COT layers A1 to A4 Transfer arm (main transfer mechanism)
D Delivery arm (main transfer mechanism)
21 Development unit (development processing section)
23 Application unit (application processing unit)
50 Ultraviolet irradiation device 51, 51A Substrate holder 52 Ultraviolet lamp (ultraviolet irradiation body)
53 Ball screw mechanism (moving mechanism, auxiliary transport mechanism)
54 Housing 60 Heating unit 61, 61A Heater 62 Heat plate 70 Oxygen cylinder (gas supply means)
73 On-off valve 80 Controller 100 Control unit

Claims (16)

A resist pattern forming method for repeatedly performing a lithography process for forming a predetermined pattern by performing lithography processing such as resist coating processing, exposure processing, and development processing on a substrate,
A first pattern forming step of applying a resist containing a crosslinking agent to the substrate, and then exposing and developing to form a first resist pattern;
An ultraviolet irradiation step of irradiating the first resist pattern after the first pattern forming step with ultraviolet rays for a predetermined time;
A heating step of heating the substrate on which the first resist pattern is formed at a predetermined temperature;
Applying a second resist to the substrate on which the first resist pattern is formed, exposing and developing to form a second resist pattern; and
A resist pattern forming method characterized by comprising: In the resist pattern formation method of Claim 1,
The method of forming a resist pattern, wherein an ultraviolet irradiation time in the ultraviolet irradiation step is 2.1 to 5 seconds. In the resist pattern formation method of Claim 1 or 2,
The ultraviolet ray irradiation step is performed by supplying oxygen gas into a processing space partitioned from the outside. In the resist pattern formation method of Claim 1 or 2,
The ultraviolet irradiation process is performed by supplying an inert gas into a processing space partitioned from the outside. In the resist pattern formation method in any one of Claims 1 thru | or 4,
A method for forming a resist pattern, wherein a heating temperature in the heating step is equal to or lower than a glass transition temperature. In the resist pattern formation method in any one of Claim 1 thru | or 5,
A resist pattern forming method, wherein the heating step is performed immediately after the ultraviolet irradiation step. In the resist pattern formation method in any one of Claim 1 thru | or 5,
A resist pattern forming method, wherein the ultraviolet irradiation step and the heating step are performed simultaneously. A resist pattern forming apparatus that repeatedly performs a lithography process for forming a predetermined pattern by performing lithography processing such as resist coating processing, exposure processing, and development processing on a substrate,
A pattern forming unit including a coating processing unit that applies a resist containing a crosslinking agent to the substrate, an exposure processing unit that exposes the substrate coated with the resist, a development processing unit that develops the exposed substrate, and the like.
An ultraviolet irradiation device that irradiates the substrate after development processing on which the first resist pattern is formed by the pattern forming unit with ultraviolet rays;
A heating unit that heats the substrate after the development processing in which the first resist pattern is formed by the pattern forming unit,
A resist pattern forming apparatus. The resist pattern forming apparatus according to claim 8, wherein
The main transport for transporting the substrate after the development processing on which the first resist pattern is formed by the pattern forming unit to the ultraviolet irradiation apparatus and transporting the substrate heated by the heating unit to the resist processing unit of the pattern forming unit A resist pattern forming apparatus, further comprising: a mechanism; and an auxiliary transport mechanism that transports the substrate irradiated with ultraviolet rays by the ultraviolet irradiation device to the heating unit. The resist pattern forming apparatus according to claim 8 or 9,
The ultraviolet irradiation apparatus includes a substrate holder that holds the substrate surface on the upper surface, an ultraviolet irradiator that irradiates the substrate held on the substrate holder with ultraviolet rays, and the substrate holder and the ultraviolet irradiator relative to each other. A resist pattern forming apparatus comprising: a moving mechanism that moves in parallel. The resist pattern forming apparatus according to claim 10, wherein
The resist pattern forming apparatus, wherein the substrate holder and the moving mechanism constitute the auxiliary transport mechanism for transporting the substrate irradiated with ultraviolet rays by the ultraviolet irradiation device to the heating unit. The resist pattern forming apparatus according to any one of claims 9 to 11,
A resist pattern forming apparatus, wherein the substrate holder, the ultraviolet irradiator, and the heating unit are disposed in a housing, and oxygen gas can be supplied into a processing space in the housing. The resist pattern forming apparatus according to any one of claims 9 to 11,
A resist pattern forming apparatus, wherein the substrate holder, the ultraviolet irradiator, and the heating unit are disposed in a casing, and an inert gas can be supplied into a processing space in the casing. The resist pattern forming apparatus according to any one of claims 9 to 13,
A resist pattern forming apparatus, wherein a heating body constituting the heating unit is disposed on the substrate holding table. The resist pattern forming apparatus according to any one of claims 8 to 14,
The resist pattern forming apparatus, wherein the ultraviolet irradiation time in the ultraviolet irradiation apparatus is set to 2.1 to 5 seconds. In the resist pattern formation apparatus in any one of Claims 8 thru | or 15,
A resist pattern forming apparatus, wherein a heating temperature in the heating unit is set to a glass transition temperature or lower.

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