JP3676947B2 - Semiconductor device manufacturing equipment, semiconductor device pattern forming method using the same, and semiconductor device manufacturing photoresist using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the manufacture of a semiconductor device. More specifically, a pattern having a preferable size is formed by performing a flow process after irradiating a photoresist pattern with UV (Ultra Violet) light after development in a photographic process. The present invention relates to a semiconductor device manufacturing equipment, a semiconductor device pattern forming method using the same, and a semiconductor device manufacturing photoresist using the same.
[0002]
[Prior art]
Usually, a semiconductor device is formed by performing a series of processes such as a vapor deposition process, a photographic process, an etching process, and an ion implantation process.
[0003]
That is, a semiconductor device is formed by patterning a thin film of several layers such as a polycrystalline film, an oxide film, a nitride film, and a metal film on a wafer and then patterning through a photo process, an etching process, an ion implantation process, and the like. To complete. The photographic process is a core technology of a semiconductor device manufacturing process in which a preferable semiconductor integrated circuit pattern is formed on the wafer by using a photo mask. The photographic process is used for manufacturing a semiconductor element of 16M DRAM, 64M DRAM, 256M and 1G DRAM or more at the time of exposure depending on the light source used. Currently, g-line (436 nm), i-line (365 nm), DUV (248 nm), KrF laser (193 nm) and the like are used as light sources for the photographic process.
[0004]
The photoresist used in the photographic process is made of a photosensitive polymer material that undergoes a chemical reaction by light and generally has a solubility or the like converted. That is, when a light is irradiated through a photomask in which a microcircuit is already formed, a chemical reaction occurs in the portion of the photoresist that is irradiated with light. When developed with an appropriate developer by being transformed into an insoluble material, respective positive or negative photoresist patterns are formed. The photoresist pattern serves as a mask in the processes after the photographic process, that is, in the etching and ion implantation processes.
[0005]
The photoresist is classified into g-line, i-line, and DUV photoresists according to the exposure wavelength, and the photoresist has a problem that it is difficult to implement a pattern having a size smaller than the exposure wavelength of the light source.
[0006]
Currently, the contact hole pattern in the photographic process has a lower resolution than the line & space pattern, and the pattern uniformity on the entire wafer surface is not good.
[0007]
Therefore, a new technique must be applied to overcome the limit resolution of the photoresist and form a contact hole pattern having a size of 0.02 μm or less required by highly integrated semiconductor devices of 64M DRAM or higher.
[0008]
Currently, the following method is used to implement a contact hole having a size smaller than the exposure wavelength.
[0009]
(1) As a flow method of a photoresist pattern, after forming a photoresist pattern of a contact hole having a preferable size or more using a general chromium (Cr) mask, the photoresist pattern is formed on the photoresist pattern. The photoresist pattern is reduced in size by applying heat at or above the softening point to reduce the softening and viscosity of the photoresist polymer to flow.
[0010]
(2) As a modified exposure method, exposure using a modified illumination and a phase shift mask (PSM: Phase Shift Mask) allows the exposure and non-exposure parts of the photoresist to be more clearly separated, and normal illumination is performed. And a photoresist pattern having a smaller contact hole than when exposed using a photomask.
[0011]
The flow method of the photoresist for i-line including Novolak Resin, PAC (Photo Active Compound), Solvent, Additives, and the like is a method in which the PAC is thermally decomposed by heat and the PAC is thermally decomposed. The difference in speed between the phenomenon in which the thermal characteristics increase due to the reaction of Resin and CrossLinking and the photoresist pattern flow phenomenon due to the decrease in viscosity due to heat is utilized. In the i-line photoresist, the flow proceeds continuously while a cross-linking reaction occurs. Therefore, the flow phenomenon is appropriately controlled by the cross-linking reaction. In other words, the flow phenomenon of the i-link photoresist proceeds fully due to the temperature change and does not greatly affect the temperature change due to the process and equipment. In the case of the i-line photoresist, a pattern having a size of 0.25 μm can be realized as a flow method.
In addition, by applying modified illumination and a phase inversion mask to the i-line photoresist, a pattern having a size of 0.28 μm could be realized.
[0012]
FIG. 1 relates to a conventional method for forming a pattern of a semiconductor device. Specifically, FIG. 1 is a process flow chart for explaining a method for forming a contact hole pattern using an i-line photoresist.
[0013]
As shown in FIG. 1, first, in step S2 of applying a photoresist on a wafer, an i-line photoresist is applied to the wafer coated with HMDS (Hexamethyldisilazane) to a predetermined thickness. In step S4 of soft baking the coated photoresist, the solvent contained in the photoresist is removed to increase the adhesive strength of the photoresist. A state in which the wafer is applied to a certain thickness on the wafer is maintained. In step S6, in which a photomask is continuously aligned and exposed on the photoresist after the soft baking, the wafer coated with the i-line photoresist is moved to an i-line stepper to move the wafer. After aligning a phase inversion mask on which a fine hole pattern is formed on the wafer, i-line passes through the phase inversion mask to irradiate the wafer coated with the photoresist for exposure. In step S8 of continuously exposing the exposed wafer to PEB (Post Exposure Bake), the exposed wafer is baked to a predetermined temperature and incident light of the exposure light source and reflected light on a photoresist pattern. The wave pattern generated by the standing wave effect generated while the reinforcement and cancellation phenomenon occur due to the interference is removed to improve the profile of the photoresist pattern and improve the resolution of the photoresist pattern. In step S10, the wafer on which the PEB has been completed is developed and washed to form the photoresist pattern. In step S10, the wafer on which the PEB has been completed is moved to a developing device, and a developer is applied onto the photoresist. To form a pattern, and then developing impurities are removed with a cleaning solution.
[0014]
In step S12, where the developed wafer is continuously hard baked, the developed photoresist pattern is dried and cured to harden the photoresist pattern.
[0015]
After the hard baking, the baking is performed in step S14, so that the photoresist polymer is softened and the viscosity is decreased by applying heat above the photoresist softening point to the photoresist pattern. The photoresist pattern is flowed to reduce the pattern size.
[0016]
[Problems to be solved by the invention]
However, when the flow method is performed using the i-line photoresist and the phase-inversion mask using the modified illumination as described above, the photoresist pattern having a resolution of 0.18 μm can be formed. The non-exposed portion is also partially exposed unevenly, resulting in non-uniform thermal characteristics of the polymer photoresist pattern. That is, at the time of baking for the flow, the amount of exposure applied to the non-exposed portion of the cell area where the pattern density is high and the peri area where the pattern density is low is non-uniform. Accordingly, the non-uniform exposure amount causes a difference in flow speed due to the effect of heat, resulting in a bulk effect in which the contact hole pattern is crushed in the boundary region between the cell region and the peri region. there were.
[0017]
Also, the DUV photoresist flow method is applied so that the DUV photoresist is thermally more fragile than the i-line photoresist, and the temperature uniformity of the baking oven used when flowing is high. There is a problem that it is difficult to obtain a contact hole pattern distribution that is considerably sensitive, flows rapidly, and has a uniform size over the entire surface of the wafer. The problem is that the flow process of the DUV photoresist differs from the flow process of the i-line photoresist during the flow. Therefore, in the case of the photoresist for DUV, since a mechanism for causing a crosslinking reaction at a temperature at which flow occurs or at a temperature lower than the flow generation temperature is lacking, it is impossible to expect an effect like that of an i-line photoresist. There was a problem.
[0018]
2 to 5 are process cross-sectional views showing contact hole pattern formation by a flow method using an i-line photoresist and a phase inversion mask according to the process sequence diagram of FIG.
[0019]
As shown in FIG. 2, an i-line photoresist 6 is applied to the wafer 2 on which the non-pattern forming film 4 is formed, and then soft-baked. As shown in FIG. 3, the phase in which the fine hole pattern is formed on the wafer 2 coated with the i-line photoresist 6 by moving the wafer 2 to the i-line stepper. The reversal mask 7 is aligned and exposure is performed using i-line. Subsequently, as shown in FIG. 4, the exposed wafer 2 is subjected to PEB, and then developed and washed to form a first contact hole pattern 8. At this time, the size of the first contact hole pattern 8 is about 0.25 μm. Subsequently, the first contact hole pattern 8 is flow-baked as shown in FIG. 10 Form.
However, when the flow is performed using the phase inversion mask using the modified illumination, the non-exposed portion is also partially exposed unevenly, and the thermal characteristics of the photoresist pattern which is a polymer becomes non-uniform, As shown in FIG. 5, there is a problem that a bulk effect (bulk effect) is generated in which the second contact hole 9 is crushed during flow baking as shown in FIG.
[0020]
An object of the present invention is to provide a pattern formation method for a semiconductor device, in which a contact hole pattern having a uniform and preferable size is formed so that a flow method is possible in a process in which an i-line photoresist and a phase inversion mask are simultaneously applied. It is to provide.
[0021]
Another object of the present invention is to provide a pattern forming method for a semiconductor device, in which a flow method is applied to a photoresist for DUV to form a contact hole pattern having a uniform and preferable size.
[0022]
It is another object of the present invention to provide a semiconductor device manufacturing equipment for the semiconductor device pattern forming method.
Still another object of the present invention is to provide a photoresist for manufacturing a semiconductor device which is applied to the pattern forming method of the semiconductor device.
[0023]
[Means for Solving the Problems]
In order to achieve the above object, a semiconductor device manufacturing apparatus according to the present invention includes a photoresist coating unit that coats a specific photoresist on a wafer, and a wafer that is exposed after the photoresist is coated. A developing unit for forming a photoresist pattern and a crosslinking reaction unit for crosslinking the photoresist pattern to provide a stable flow during the photoresist pattern flow process.
The semiconductor device manufacturing equipment is one of a spinner and a track equipment.
[0024]
The semiconductor device manufacturing equipment includes an HMDS coating unit for increasing the adhesion force of the photoresist to the wafer surface transferred from the wafer loading unit before transferring the wafer to the photoresist coating unit, and the photoresist. A bake unit that can bake the coated wafer, the exposed wafer, and the developed wafer, and a wafer edge exposure (WEE) unit that exposes a predetermined width of the wafer edge portion are further installed. It is preferable.
[0025]
It is preferable that one or more of the wafer loading unit, the HMDS coating unit, the photoresist coating unit, the developing unit, the baking unit, the wafer edge exposure unit, and the crosslinking reaction unit are installed.
[0026]
The baking part includes a soft baking part for removing a solvent contained in the photoresist applied to the wafer, and a PEB for removing a standing wave having a fine structure appearing in the photoresist pattern. A (Post Exposure Bake) part and a hard bake part for curing the photoresist pattern are divided.
[0027]
The crosslinking reaction part is a UV baking part for irradiating the developed wafer with UV light.
The UV bake unit includes a UV lamp (Lamp) that generates UV at an upper portion thereof, and a hot plate (Hot) that can heat the wafer while a wafer is seated at a predetermined interval from the UV lamp at a lower portion. Plate).
[0028]
The UV lamp is an ultra-high frequency excitation lamp (Microwave-ExcitedLamp) or a Mercury-Xenon Arc Lamp.
[0029]
In the semiconductor device manufacturing equipment, a process chamber in which an etching process of a lower film quality using the photoresist pattern as an etching mask is performed is further positioned at a position where the wafer can be easily transferred between the process chamber and the crosslinking reaction part. Can be equipped.
[0030]
The semiconductor device manufacturing equipment further includes a load lock chamber connecting the cross-linking reaction part and the process chamber.
The crosslinking reaction part may be a UV bake part for irradiating the developed wafer with UV light.
[0031]
A method of forming a pattern of a semiconductor device according to the present invention includes: applying a photoresist on a wafer; aligning and exposing a photomask on the photoresist; and forming a photoresist pattern on the wafer; The method includes a step of cross-linking the photoresist pattern and a step of flow baking the photoresist pattern after the cross-linking reaction.
[0032]
The photoresist is preferably for i-line or dip UV (DUV: Deep Ultraviolet), and when the i-line photoresist is used, the photomask can be a phase shift mask (PSM).
[0033]
The i-line photoresist is a positive photoresist composed of a base resin, a photoactivator, a solvent and the like, and 2, 4, 6-triamino-1 is used as an additive for activating the crosslinking reaction of the photoresist pattern. Those containing 3,5-triazine can be used.
[0034]
The photoresist pattern may be a contact hole pattern, and the crosslinking reaction may be UV baking the photoresist pattern.
[0035]
In the UV baking, it is preferable to simultaneously perform a baking process using heat at a temperature lower than that of the flow baking while irradiating the photoresist pattern with UV light.
A hard baking step may be further added before the UV baking step.
[0036]
At the time of the UV light irradiation, the process time is preferably 10 to 80 seconds. At the time of the UV baking, the process temperature of the heat baking process is 50 to 140 ° C., the process temperature of the flow baking is 140 to 200 ° C., During flow baking, the process time is preferably 80 to 120 seconds.
The flow bake can be repeated one or more times.
[0037]
Another cross-linking reaction according to the present invention includes a step of hard baking the photoresist pattern and a step of developing the photoresist pattern after the hard baking.
After the hard baking, the development process of the photoresist pattern can be repeated twice or more.
[0038]
In order to achieve another object of the present invention, a photoresist according to the present invention is an i-line photoresist composed of a base resin, a photoactivator, a solvent, and the like, and is a crosslinking reaction of a photoresist pattern. 2,4,6-triamino-1,3,5-triazine is included as an additive for activating.
[0039]
At this time, the 2,4,6-triamino-1,3,5-triazine is preferably contained in an amount of 0.001 to 5% by weight based on the total amount of the base resin, the photoactivator and the solvent.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a phenomenon in which a pattern is crushed during a flow process of the photoresist pattern by irradiating the photoresist pattern with UV light after developing in a photographic process in order to reduce the line width due to higher integration of semiconductor elements. For manufacturing semiconductor device capable of effectively forming a preferable pattern size by preventing the above, a pattern forming method of semiconductor device using the same, and a photoresist for manufacturing semiconductor device using the same It is.
[0041]
Hereinafter, a specific embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 6 is a block diagram for explaining an embodiment of the semiconductor device manufacturing equipment according to the present invention, and FIG. 7 is a cross-sectional view for explaining the UV bake portion to which the ultra high frequency excitation lamp of FIG. 6 is attached. .
[0042]
FIG. 6 shows a state in which the semiconductor device manufacturing equipment 30 and the exposure equipment 90 according to this embodiment are connected in-line through an interspace 80.
[0043]
The semiconductor device manufacturing equipment 30 includes a wafer loading unit 32 on which a wafer cassette containing a wafer is loaded, and an HMDS coating unit for increasing the adhesion of the photoresist to the surface of the wafer transferred from the wafer loading unit 32. 34, a photoresist coating unit 36 for coating a photoresist on a wafer coated with HMDS by the HMDS coating unit 34; and after the photoresist is coated by the photoresist coating unit 36, the exposed wafer is developed. A developing unit 44 for forming a photoresist pattern, a soft bake unit 38 for removing a solvent contained in the wafer coated with the photoresist, after exposure of the wafer coated with the photoresist, The fine structure that appears in the photoresist pattern A PEB unit 42 for removing a standing wave, a bake unit 37 including a hard bake unit 40 for curing the photoresist pattern, and UV on a wafer on which a photoresist pattern is formed by the development. When the photoresist pattern is subjected to a crosslinking reaction by irradiating light, the UV baking portion 48 is included as a crosslinking reaction portion that provides a stable flow during the photoresist pattern flow process.
[0044]
The semiconductor device manufacturing equipment 30 may be one of a spinner and a track equipment, and the semiconductor device manufacturing equipment 30 is further provided with a wafer edge exposure unit 46 that exposes an edge portion of the wafer by a predetermined width. Is preferred.
[0045]
The semiconductor device manufacturing equipment 30 includes a wafer loading unit 32, an HMDS coating unit 34, a photoresist coating unit 36, a developing unit 44, a soft bake (Soft Bake) for an efficient multi-process of the semiconductor device manufacturing process. ) Part 38, PEB part 42, hard bake part 40, wafer edge exposure part 46, and UV bake part 48 are preferably installed.
[0046]
The UV bake unit 48 includes a UV lamp capable of generating UV at the upper part of the chamber and a hot plate at the lower part of the chamber, which is spaced apart from the UV lamp by a predetermined distance to heat the wafer. .
[0047]
The UV lamp is preferably a very high frequency excitation lamp or a mercurizenone lamp. When the UV bake part 48 to which the ultra-high frequency excitation lamp 60 is mounted is examined in an actual example, the mercury bulb 62 to which the ultra-high frequency guide 61 is attached, the mercury bulb 62 is wrapped, and is given by the ultra-high frequency guide 61. The ultra-high frequency excitation lamp 60 including the reflecting mirror 63 having a quartz plate 64 attached to the lower surface for concentrating the UV light emitted from the mercury bulb 62 by the ultra-high frequency on the wafer is separated from the ultra-high frequency excitation lamp 60 by a predetermined distance. A wafer 68 is attached and a hot plate 70 capable of heating the wafer 68 is provided.
[0048]
When the wafer 68 is mounted on the hot plate 70, the ultra high frequency guide 61 applies energy to the mercury bulb 62 in which mercury is contained to generate UV by generating mercury in a plasma state.
UV generated by diverging in several directions is reflected by the reflecting mirror 63 and efficiently reaches the wafer 68.
[0049]
When the operation sequence of the semiconductor device manufacturing facility 30 according to the present embodiment is examined, when the wafer cassette containing the wafer is first loaded into the wafer loading unit 32, the wafer is loaded into the HMDS coating unit 34 by the first transfer arm 50. It is transferred to. The HMDS application unit 34 applies HMDS having a predetermined thickness so that a photoresist is effectively applied to the wafer.
[0050]
Subsequently, the wafer coated with the HMDS is transferred to the photoresist coating unit 36 by the second transfer arm 52, and a specific photoresist in a specific process is applied to the wafer surface. It is a fact known to those skilled in the art that the transfer arms 50 and 52 are merely attached to illustrate one embodiment and are not limited to a particular position.
[0051]
Continuously, the wafer coated with the photoresist is transferred to the soft bake unit 38 and baked at a predetermined temperature, and the photoresist coated by removing the solvent contained in the photoresist has a certain thickness. The state where it was applied to is maintained.
[0052]
Subsequently, the wafer subjected to the soft bake is transferred to the exposure equipment 90 through the inter-pace 80 to perform the exposure. The wafer subjected to the exposure passes through the wafer edge exposure unit 46, is transferred to the PEB unit 42, is baked at a predetermined temperature, and is reinforced by the interference between the incident light of the exposure light source and the reflected light after development. Further, the wave pattern generated by the standing wave effect generated while the canceling phenomenon occurs is removed, and the pattern profile is improved.
[0053]
Subsequently, the wafer on which PEB has been completed is transferred to the developing unit 44, and a developer is sprayed onto the wafer surface to form a positive photoresist pattern or a negative photoresist pattern by exposure. At this time, the line width of the photoresist pattern is larger than the preferable line width.
[0054]
Subsequently, the wafer is transferred to a UV bake unit 48 and subjected to a UV irradiation and hot plate baking process on the photoresist pattern to cause a cross-linking reaction in the photoresist. The photoresist pattern is flow-baked to obtain a photoresist pattern smaller than the first photoresist pattern after development.
[0055]
The unit process parts of the manufacturing equipment 30 of the semiconductor device can be changed in order for convenience, and the unit process parts in order to increase the efficiency of the occupied area in the Fab Line of the manufacturing equipment 30. Those skilled in the art will appreciate that can be arranged in a vertical configuration.
[0056]
An important point of the semiconductor device manufacturing equipment 30 according to the present embodiment is that the UV baking portion 48 is attached to a conventional spinner or track equipment, and the special position of the UV baking portion 48 is not limited. The position of the UV bake unit 48 is such that the UV bake is performed after the development process in the process order, and is preferably arranged close to the development unit 44.
[0057]
Accordingly, the wafer on which the photoresist pattern is formed after passing through the semiconductor device manufacturing facility 30 to which the UV bake unit 48 is added is moved to an etching apparatus in a subsequent process, and the lower film quality is etched using the photoresist pattern as an etching mask. Thus, an element pattern is formed.
[0058]
As described above, the device pattern forming method of the present embodiment performs the etching process after performing the UV baking and the flow baking on the photoresist pattern formed by the developing process, and the UV baking part is added. An etching pattern can be used to form an element pattern.
[0059]
Accordingly, the etching apparatus irradiates the photoresist pattern on the wafer formed by the development process with UV light to provide a stable flow during the flow process of the photoresist pattern on the wafer. A process chamber in which an etching process of a lower film quality using the photoresist pattern as an etching mask is performed adjacent to the bake part and the UV bake part is included.
[0060]
The UV bake unit and the process chamber are preferably connected to a load lock chamber in terms of process efficiency.
FIG. 8 is a process sequence diagram illustrating a method for forming a pattern of a semiconductor device according to an embodiment of the present invention.
[0061]
As shown in FIG. 8, the method of forming the pattern of the semiconductor device can be performed by selecting one of the three steps after the development and cleaning steps. The three process orders are A, B, and C. First, the description was made with respect to the A order, and in the description of the order of B and C, the description overlapping with the A order was omitted.
First, when the order of process A is examined, i-line photoresist is coated on the wafer in step S20, where the photoresist is first coated on the wafer.
[0062]
In order to increase the adhesive force of the i-line photoresist by removing the solvent included in the photoresist as a step S22 in which the applied i-line photoresist is continuously soft-baked. Perform soft bake.
[0063]
At this time, the i-line photoresist is a positive photoresist composed of a base resin, a photoactivator, a solvent, and the like, and 2, 4, 6-triamino- as an additive for activating the crosslinking reaction of the photoresist pattern. It can be used that 1,3,5-triazine is contained in an amount of 0.001 to 5% by weight based on the total amount of the base resin, photoactivator and solvent. The 2,4,6-triamino-1,3,5-triazine is a so-called melamine, and its chemical formula is C. _Three H ₆ N ₆ Thus, melamine formaldehyde resin is formed by addition condensation reaction with formaldehyde.
[0064]
Subsequently, in step S24 of aligning a photomask on the photoresist after the soft bake and exposing the photoresist, the wafer coated with the i-line photoresist is moved to the i-line stepper to move the wafer. A phase inversion mask having a fine hole pattern formed on the wafer is aligned, and i-line is incident on the wafer through the phase inversion mask to expose the wafer.
[0065]
Continuously, as step S26 of PEBing the exposed wafer, the PEB is generated due to a standing wave effect that occurs while reinforcement and cancellation phenomenon occur due to interference between incident light and reflected light of the exposure light source of the photoresist pattern. The wave pattern is removed to improve the pattern profile and improve the resolution of the photoresist pattern.
[0066]
Subsequently, in step S28, the photoresist pattern is formed by developing and cleaning the wafer on which the PEB has been completed. In step S28, the wafer on which the PEB has been completed is moved to a developing device, and a developer is applied onto the photoresist. Then, after forming a pattern, the developing impurities are removed in the cleaning solution.
[0067]
Subsequently, in step S32 of UV-baking the photoresist pattern, heat is applied to the photoresist pattern while irradiating UV light so that a cross-linking reaction occurs in the photoresist. Ensure thermal safety and be insensitive to heat during flow due to temperature rise. The UV bake may be performed simultaneously with a heat baking process while irradiating the photoresist pattern with UV light, and the heat baking process may be performed independently after the UV light is irradiated.
[0068]
Subsequently, after the UV baking, the photoresist pattern is flow-baked in step S36, and heat above the softening point of the photoresist is applied to the photoresist pattern to soften the photoresist polymer and reduce its viscosity. Thus, the photoresist pattern is flowed to reduce the size of the pattern. In addition, the difference in the flow rate of the photoresist pattern between the cell area where the pattern density is high and the peri area where the pattern density is low is not large, and the photoresist pattern is uniformly formed on the entire surface of the wafer.
[0069]
Subsequently, step B30 is further added to the step B30 in order to perform the flow process a little more stably before the step S32 in which the photoresist pattern is UV-baked in the step A.
[0070]
Finally, the C process sequence is such that a crosslinking reaction occurs in the photoresist performed in the A process sequence, so that the thermal stability of the photoresist pattern is ensured and the heat is insensitive to the flow due to the temperature rise. Instead of the UV baking step S32, the hard baking step S33 and the same developing solution used in the developing step S28 are performed in the same manner as in the developing step S34. Carry out one after another. That is, in the C process sequence, the photoresist pattern formed in the developing process is treated with a developer to change the characteristics of the photoresist, and the same characteristics as the UV baking are obtained.
[0071]
9 to 12 illustrate a process sequence A in process cross-sectional views showing contact hole pattern formation by a flow method using the i-line photoresist and the phase inversion mask according to the process sequence diagram of FIG.
[0072]
As shown in FIG. 9, after the i-line photoresist 16 is applied to the wafer 12 on which the non-pattern forming film 14 is formed, soft baking is performed at 80 to 120 ° C. for 50 to 100 seconds. In the soft baking, the i-line photoresist 16 applied by removing the solvent contained in the i-line photoresist 16 is maintained in a state of being applied with a certain thickness. A preferable process temperature of the soft baking is 90 to 110 ° C.
[0073]
In this case, the i-line photoresist is composed of 2,4,6-triamino-1,3,5-triazine as the base resin, photoactivator, solvent and additive in the total amount of base resin, photoactivator and solvent. On the other hand, a positive photoresist contained in an amount of 0.001 to 5% by weight can be used.
[0074]
Subsequently, as shown in FIG. 10, the wafer 12 is moved to the i-line stepper, and the transfer reversal mask 17 in which the fine hole pattern is formed on the i-line photoresist 16 is aligned. -Perform exposure using line.
[0075]
Subsequently, as shown in FIG. 11, the exposed wafer 12 is subjected to PEB at 100 to 140 ° C. for 50 to 100 seconds, and then developed and washed to form a first contact hole pattern 18. The PEB is performed for the purpose of improving the profile of the pattern by removing a standing wave having a fine structure appearing in a pattern made of a photoresist, thereby increasing the resolution. At this time, the size of the first contact hole pattern 18 is about 0.28 μm, and the uniformity of the first contact hole pattern 18 on the entire surface of the wafer 12 is not good.
[0076]
Subsequently, as shown in FIG. 12, the first contact hole pattern 18 is continuously subjected to UV baking and flow baking to form a second contact hole 20 having a size smaller than that of the first contact hole pattern 18 of 0.20 μm or less. Form. The UV baking is performed by simultaneously applying heat while irradiating the first contact hole pattern 18 with UV light. The irradiation time of the UV light is 10 to 80 seconds, preferably 10 to 50 seconds. The temperature of baking by heat is 50 to 140 ° C., preferably 110 ° C. That is, the first contact hole pattern 18 is thermally stabilized by the UV light irradiation and baking, so that a crosslinking reaction occurs in the first contact hole pattern 18.
[0077]
After performing the UV baking continuously, the UV light irradiation is stopped, the wafer is moved to the same chamber or an independent baking chamber, and the flow baking is performed at 140 to 200 ° C. for 80 to 120 seconds. Then, the second contact hole 20 is formed. The process temperature of the flow baking is preferably 170 to 190 ° C. Therefore, at the time of flow baking, there is a large difference in the degree of polymer flow between the dense portion where the pattern is repeatedly present and the portion where the pattern is not present, and the bulk effect (Bulk effect) that the generated pattern is crushed does not occur and exposure is performed. Second contact holes 20 smaller than the light source and having a size of 0.20 μm or less are uniformly formed on the entire surface of the wafer 12. The flow baking may be repeated one or more times depending on the type of photoresist and the flow amount.
[0078]
Accordingly, when the characteristics of the manufacturing equipment of the present embodiment having the above-described configuration are examined, an etching process can be performed by adding a UV bake 48 as a cross-linking reaction part to a conventional spinner or truck equipment, and using a normal etching equipment. By installing the UV bake 48 adjacent to the chamber, the equipment efficiency can be increased and a smooth flow bake process can be performed.
All of the i-line photoresist and the DUV photoresist are applied to the pattern forming method of this embodiment.
[0079]
There are two cases of the photoresist. That is, there are negative photoresists that are insoluble in developer when exposed to light and positive photoresists that are soluble in developer when exposed to light. In this example, the positive photoresist for i-line is a novolak resin as a base resin (Resin), a diazonaphthoquinone base as a photoactivator, and a polyhydroxy resin as a blast system (Ballast Group). Consists of a structure to which benzopinone (Polyhydroxy Benzophenone) is bonded and 2-heptanone as a solvent, and 2,4,6-triamino-1,3,5-triazine called so-called melamine is added as an additive By doing so, the flow effect of the photoresist pattern can be further improved.
In general, when UV irradiation or baking is performed on a positive photoresist, an acid is generated to make the positive photoresist soluble.
[0080]
Therefore, the addition of additives to the positive photoresist helps the crosslinking reaction on the positive photoresist, and as a result, the flow process of the present invention is considerably improved. That is, by adding 2,4,6-triamino-1,3,5-triazine to the i-line positive photoresist, the crosslinking reaction between the resins is further activated under an acid catalyst, and the photoresist Thermal properties are improved.
[0081]
【The invention's effect】
Therefore, according to the present invention, as described above, after forming the photoresist pattern, the photoresist pattern is irradiated with UV light to induce a crosslinking reaction in the polymer of the photoresist pattern, thereby thermally stabilizing the photoresist. As the flow progresses, there is a large difference in the flow rate of the polymer between the dense part where the pattern repeats and the part where there is no pattern, and the generated pattern is flat and uniform without causing the bulk effect. There is an effect that the size of the photoresist pattern can be formed smaller than the wavelength of the exposure light source.
[0082]
Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention. Naturally, various changes and modifications should be within the scope of the appended claims.
[Brief description of the drawings]
FIG. 1 is a process sequence diagram illustrating a conventional method for forming a pattern of a semiconductor device.
FIG. 2 is a process cross-sectional view illustrating a method for forming a pattern of a semiconductor device according to the process sequence diagram of FIG. 1;
3 is a process cross-sectional view illustrating a method for forming a pattern of a semiconductor device according to the process sequence diagram of FIG. 1;
4 is a process cross-sectional view illustrating a semiconductor element pattern forming method according to the process sequence diagram of FIG. 1; FIG.
5 is a process cross-sectional view illustrating a method of forming a semiconductor element pattern according to the process sequence diagram of FIG. 1; FIG.
FIG. 6 is a block diagram for explaining an embodiment of a semiconductor device manufacturing equipment according to the present invention.
7 is a cross-sectional view for explaining a UV bake part of the semiconductor device manufacturing equipment of FIG. 6;
FIG. 8 is a process sequence diagram illustrating a method of forming a pattern of a semiconductor device according to an embodiment of the present invention.
FIG. 9 is a process cross-sectional view illustrating a method for forming a pattern of a semiconductor device according to the process sequence diagram of FIG. 8;
10 is a process cross-sectional view illustrating a semiconductor element pattern forming method according to the process sequence diagram of FIG. 8; FIG.
11 is a process cross-sectional view illustrating a semiconductor element pattern formation method according to the process sequence diagram of FIG. 8; FIG.
12 is a process cross-sectional view illustrating a semiconductor element pattern forming method according to the process sequence diagram of FIG. 8; FIG.
[Explanation of symbols]
2, 12 wafers
4, 14 Non-patterned film
6,16 Photoresist
7, 17 Phase reversal mask
8, 18 First contact hole pattern
9, 20 Second contact hole pattern
30 Semiconductor device manufacturing equipment
32 Loading section
34 HMDS application part
36 Photoresist application part
37 Bake Club
38 Soft baking
40 Hard bake
42 PEB Department
44 Developer
46 Wafer edge exposure part
48 UV baking section
50 First transfer arm
52 Second transfer arm
60 UV lamp
61 Ultra High Frequency Guide
62 Mercury bulb
63 Reflector
64 Quartz plate
70 hot plate
80 Interpace
90 Exposure equipment

Claims (24)

A photoresist coating section for coating a specific photoresist on the wafer;
A developing unit for forming a photoresist pattern on the exposed wafer after the photoresist is applied;
A crosslinking reaction part for crosslinking the photoresist pattern to provide a stable flow during the flow process of the photoresist pattern;
A device for manufacturing a semiconductor device, comprising:   The semiconductor device manufacturing equipment according to claim 1, wherein the equipment is one of a spinner and a truck equipment. An HMDS coating unit for increasing the adhesion force with the photoresist on the wafer surface transferred from the wafer loading unit before transferring the wafer to the photoresist coating unit;
A baking part capable of baking the wafer coated with the photoresist, the exposed wafer and the developed wafer;
A wafer edge exposure unit that exposes a predetermined width of the edge portion of the wafer;
The apparatus for manufacturing a semiconductor device according to claim 1, further comprising: 4. The wafer loading unit, the HMDS coating unit, the photoresist coating unit, the developing unit, the baking unit, the wafer edge exposure unit, and the crosslinking reaction unit are installed in one or more. Equipment for manufacturing semiconductor devices.   2. The apparatus for manufacturing a semiconductor device according to claim 1, wherein the cross-linking reaction part is a UV bake part for irradiating the developed wafer with UV light. The UV bake part is
A UV lamp that generates UV at the top;
A hot plate capable of heating the wafer, the wafer being seated at a lower portion and spaced apart from the UV lamp by a predetermined distance;
The semiconductor device manufacturing equipment according to claim 5, comprising:   7. The apparatus for manufacturing a semiconductor device according to claim 6, wherein the UV lamp is an ultra-high frequency excitation lamp or a mercurizenone arc lamp.   A process chamber in which an etching process of the lower film quality on the wafer using the photoresist pattern as an etching mask is performed is further provided at a position where the wafer can be easily transferred between the process chamber and the crosslinking reaction part. The semiconductor device manufacturing equipment according to claim 2, characterized in that:   9. The apparatus for manufacturing a semiconductor device according to claim 8, further comprising a load lock chamber connecting the cross-linking reaction part and the process chamber. Applying photoresist on the wafer;
Aligning and exposing a photomask on the photoresist; and
Forming a photoresist pattern on the wafer;
Crosslinking the photoresist pattern;
After the cross-linking reaction, flow baking the photoresist pattern;
A method of forming a pattern of a semiconductor element, comprising:   The method of claim 10, wherein the photoresist is for i-line or dip UV.   The method of claim 11, wherein a phase inversion mask is used as the photomask when the i-line photoresist is used.   The i-line photoresist is a positive photoresist composed of a base resin, a photoactivator, a solvent and the like, and 2, 4, 6-triamino is used as an additive for activating the crosslinking reaction of the photoresist pattern. The method for forming a pattern of a semiconductor device according to claim 12, comprising -1,3,5-triazine.   The method of claim 10, wherein the photoresist pattern is a contact hole pattern.   The method according to claim 10, wherein the cross-linking reaction causes the photoresist pattern to be UV-baked.   16. The method of claim 15, wherein the UV baking is performed by simultaneously performing a heat baking process while irradiating the photoresist pattern with UV light.   16. The method of claim 15, further comprising a hard baking step before the UV baking step.   The method of claim 16, wherein a process temperature of the heat baking process is 50 to 140 ° C.   The method of claim 16, wherein the process time is 10 to 80 seconds when the UV light is irradiated.   The method of claim 10, wherein the process temperature of the flow baking is 140 to 200 ° C.   21. The method of claim 20, wherein a process time is 80 to 120 seconds during the flow baking.   The method of forming a pattern of a semiconductor device according to claim 10, wherein the flow baking is repeated one or more times. The crosslinking reaction is
Hard baking the photoresist pattern;
Treating the photoresist pattern after the hard baking with a developer for forming the photoresist pattern;
The pattern formation method of the semiconductor element of Claim 10 characterized by the above-mentioned.   24. The method of claim 23, wherein after the hard baking, the photoresist pattern development process is repeated twice or more.

Images