JP3852157B2 - Method for producing ultraviolet photosensitive chemically amplified resist and method for inspecting ultraviolet photosensitive chemically amplified resist - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention inspects whether or not a heterogeneous raw material is mixed in the raw material of the ultraviolet photosensitive chemically amplified resist, and further produces a homogeneous ultraviolet photosensitive chemically amplified resist based on the inspection result. Regarding technology.
[0002]
[Prior art]
Conventionally, in the manufacturing process of a semiconductor device, various patterns such as a wiring layer, an insulating layer, and an active region are formed by applying a photoengraving technique, and a photoresist is exclusively used for this purpose. In recent years, semiconductor devices are remarkably miniaturized and densified, and it is therefore necessary to accurately draw a fine pattern.
[0003]
For the convenience of application to the surface of a semiconductor substrate, the photoresist is made of a mucus mixed with a solvent-sensitive material sensitive to exposure light. If the molecular weight or composition of the substrate itself is not uniform, the problem that it is difficult to accurately draw a fine pattern of a semiconductor device or a mask substrate is revealed. Therefore, the photosensitive composition contained in the prepared photoresist solution is appropriately inspected before actual use, and if it is excessively inhomogeneous, remove it and remove only as homogeneous as possible. The use of strict control of homogeneity is becoming necessary.
[0004]
In the current exposure process for manufacturing a semiconductor device or a mask substrate, as the fine pattern width is more strongly demanded, ultraviolet rays having a shorter wavelength are used instead of the conventional exposure light. For example, i-line (365 nm) of a mercury lamp has been widely used in the past. However, even in the most advanced ultra-fine device, even this i-line has a long wavelength, and the wiring pattern cannot be accurately drawn. The pursuit of technology in the short wavelength region has been made. In other words, KrF (krypton fluoride) excimer laser light (248 nm) and even shorter wavelength ArF (argon fluoride) excimer lasers are candidates for exposure light for the most advanced devices currently being developed. The pursuit of light (193 nm) and the deep ultraviolet region is also being carried out.
[0005]
By the way, when using such deep ultraviolet light, it is naturally assumed that a material that can transmit such light is used as a resist material. However, conventional novolak resists are conjugated double benzene rings that form a molecular skeleton. Since the coupled system has deep absorption, it has the disadvantage that it cannot transmit vacuum deep ultraviolet light, and is not practically used. Therefore, it is required to design a new resist material, and materials that do not have a benzene ring as a skeleton used for this purpose, such as adamantyl methacrylate resist and norbornene methacrylate resist, are promising. Such a photoresist corresponding to the deep ultraviolet region usually takes a new reaction mode called a chemical amplification type at the time of exposure because of the necessity of accurately drawing a fine pattern. That is, a chemically amplified photoresist contains a compound called a photoacid generator (PAG) together with a resin base material, and PAG positively generates an acid upon receiving light, and this acid works on the resin base material to bond. Create a state that can form. As described above, it is essential that the photoresist corresponding to the deep ultraviolet region contains PAG having absorption at a wavelength similar to that of the resin base material itself.
[0006]
However, since the PAG having the same absorption region and the resin base material must be included, the ultraviolet absorption spectra of each other overlap each other, and it is difficult to separate and identify each other only by measuring the ultraviolet absorption spectrum. It is not possible to know the composition ratio of the two by simply measuring the ultraviolet absorption spectrum. Therefore, establishment of another easy measurement method is required for identification of the composition ratio of such a new resist material.
[0007]
[Problems to be solved by the invention]
As described above, the problem to be solved by the present invention is to develop a measurement method for easily identifying a resist composition in a chemically amplified resist material compatible with ultraviolet light exposure, thereby improving the homogeneity of the new resist material. Establishing is also an issue.
[0008]
[Means for solving the problems and their effects]
The above problem can be solved by the following means. That is,
As the first invention,
For UV-sensitive chemically amplified resists that contain both a photoacid generator and a resin base material, molecular weight fractionation by the GPC (gel permeation chromatography) method and UV absorption / transmittance measurement are sequentially performed. And a method for producing an ultraviolet-sensitive chemically amplified resist having a step of sorting out only the homogeneous chemically amplified resist based on the molecular weight fractionation result and the composition ratio obtained from the ultraviolet absorption rate or transmittance measurement result, Means.
[0009]
As a second invention,
For UV-sensitive chemically amplified resists that contain both a photoacid generator and a resin base material, molecular weight fractionation by the GPC (gel permeation chromatography) method and UV absorption / transmittance measurement are sequentially performed. performed, to check the method of UV-sensitive chemically amplified resist comprising a step of determining the molecular weight fractionation results and the ultraviolet absorptivity to transmittance measurements or al sets composition ratio, the a unit.
[0010]
As described above, in the present invention, the molecular weight fractionation by the GPC (gel permeation chromatography) method and the ultraviolet absorption spectrum measurement are sequentially performed on the ultraviolet photosensitive chemically amplified resist, and a photoacid generator ( The composition ratio between the absorption maximum corresponding to the molecular weight of PAG) and the absorption maximum corresponding to the molecular weight of the resin substrate is determined. By determining the composition ratio, the homogeneity in the resist material is measured.
[0011]
In order to confirm that the chemically amplified resist is manufactured as designed, it is necessary to confirm the following points.
(1) Dissolution rate of resin base material,
(2) Molecular weight of resin base material,
(3) Protection rate of the resin base material, that is, a ratio in which a protective group that reacts with the photoacid generator is added to or substituted on the resin base material,
(4) Amount of photoacid generator,
(5) Ratio of photoacid generator and resin base material,
(6) If there is a low molecular weight substance other than the photoacid generator, the amount.
[0012]
If the means of the present invention is employed, the ultraviolet absorption spectrum can be measured in order for each composition that is sorted and flowed out after first being sorted in the resist according to molecular weight, and has the following effects.
(1) The molecular weight of the resin base material can be confirmed by paying attention to the ultraviolet absorption peak of the resin base material flowing out from the GPC.
(2) The amount of the acid generator can be confirmed from the ultraviolet absorption peak at the portion corresponding to the molecular weight of the acid generator.
(3) The ratio (composition ratio) between the acid generator and the resin can be confirmed from the ratio of the ultraviolet absorption peak corresponding to the molecular weight of the resin and the peak intensity ratio of the ultraviolet absorption corresponding to the molecular weight of the acid generator.
(4) When there is a low molecular weight substance other than the acid generator, the amount of the substance can be confirmed from the ultraviolet absorption peak corresponding to the molecular weight.
(5) If there is an abnormal ultraviolet absorption or molecular weight peak, it means that a substance that should not be included in the resist (which should not have been included in the resist design stage) is mixed. Prevents contamination of other substances.
[0013]
As described above, the resist can be easily inspected by using the present invention.
Basically, (1) the molecular weight of the resin substrate, (2) the dissolution rate of the resin substrate, and (3) the protection rate of the resin substrate can be inspected by the resin substrate alone, so even without using the present invention. Can be inspected. Generally, it is performed by raw material acceptance inspection. However, if it becomes a mixture like a resist, it cannot be inspected unless it is the present invention.
[0014]
According to the present invention, a high molecular weight resin base material and a low molecular weight photoacid generator (PAG) are separated and identified, and their absorption characteristics can be easily separated even if the respective ultraviolet absorptions are overlapped. Although it is effective in that the composition ratio between the resin base material and the photoacid generator can be identified even in a solution state, the GPC method causes a time lag especially when the GPC method is selected by molecular weight classification. The ultraviolet absorption spectrum can be measured in order for each mixture that comes out, and the inspection efficiency is higher.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below based on one embodiment. Needless to say, the present invention is not limited to such an embodiment and can be widely modified.
As an example of a resist material, a chemically amplified resist using a PVP (polyvinylphenol) resin as a resin and TPS (triphenylsulfonium triflate) as a photoacid generator (PAG) is taken up. PVP resin has ultraviolet absorption at 320 nm or less, and its absorption maximum is about 280 nm. On the other hand, TPS has ultraviolet absorption below 280 nm, and its absorption maximum is around 235 nm. In the resist measured here, the composition ratio between the PVP resin and the photoacid generator (PAG) was PVP resin: photoacid generator (PAG) = 100: 3.
[0016]
FIG. 1 is a configuration diagram of a measuring apparatus according to an embodiment of the present invention, and schematically shows an overall configuration of a measuring system that can be used in the measuring method of the present invention. In the figure, reference numeral 1 denotes a resist to be inspected. A solvent 2 as a solvent for the resist 1 is flowed at a constant flow rate through a pump 3 and mixed with the resist 1 so as to have an appropriate viscosity. It is used for the manufacturing process and mask making process. A mixture of the resist 1 and the solvent 2 (hereinafter referred to as a resist mixture for convenience) is supplied to the pre-column 4. The pre-column 4 is provided to remove impurities (particles) mixed in from the resist mixture serving as a measurement object before measurement, and is useful for specifying a more accurate composition ratio. Next, each molecular weight of the composition mixed through the GPC column 5 is specified. In this GPC column 5, each component of the resist mixture is separated for each molecular weight. That is, those having a high molecular weight pass through the GPC column 5 early, and those having a low molecular weight pass through the GPC column 5 slowly. That is, the time for passing through the GPC column 5 differs for each component due to the difference in molecular weight, and thus the components can be sequentially separated for each component. For example, a resin having a high molecular weight passes through the GPC column 5 quickly, and an acid generator having a low molecular weight increases the passage time through the GPC column 5. In the present invention, the components of the resist component are separated by molecular weight fractionation of the UV absorption overlap, so it is necessary to provide the GPC column 5 before the ultraviolet spectrometer 6 (photodiode array detector) as shown in the configuration diagram. Thus, the molecular weight separated resist flows into the ultraviolet spectrometer 6 (photodiode array detector), and the ultraviolet absorption for each molecular weight is measured. The ultraviolet absorption data measured by the ultraviolet spectrometer 6 is converted into three-dimensional data by the data processor 7. This three-dimensional data takes the molecular weight in the x direction, takes the wavelength (nm) in the y direction, takes the absorption value in the z direction, and knows the data of the molecular weight versus the absorption value when the wavelength changes as a whole. It can be configured so that it can be output by a printer so that the measurer can see it, or it can be configured to display it on a display, but it does not necessarily require the output of such 3D data as a whole, It is only necessary to have such a three-dimensional data conversion process in the process of data processing and automatically set a calibration curve. From the three-dimensional data recorded here, the UV absorption peak value of the molecular weight corresponding to the resin base material and the acid generator is read, and the concentration of each component can be determined by comparing it with a known calibration curve. The resist mixture is then processed as waste liquid 8 through an ultraviolet spectrometer 6. The ultraviolet spectroscope 6 is connected to a data processing device 7 for data analysis of the spectral analysis result obtained therefrom, and the measurer uses the ultraviolet spectroscopic analysis result and the GPC column 5 compiled by the data processing device 7. The composition ratio can be specified based on the obtained molecular weight analysis result.
[0017]
The method used in the conventional resist shipping test and acceptance test, the resist dilution solution is measured with an ultraviolet spectrometer 6 and ultraviolet rays are obtained by determining the composition ratio from the resin base material, photoacid generator (PAG), and respective absorption maxima. An attempt was made to determine the composition ratio by measuring the absorption, but the composition ratio could not be determined because the absorption maximum of TPS overlapped with the absorption of the PVP resin. On the other hand, according to the present invention, the GPC (gel permeation chromatography) method and the UV photodiode array detector were combined, and as a result of measuring the ultraviolet absorption while classifying the molecular weight, PVP (polyvinylphenol) resin and TPS were measured. In (triphenylsulfonium triflate), the molecular weight of the former is 412.2 and the molecular weight of the latter is greatly different from the molecular weight of about 5000 to 10,000. By combining, each absorption maximum can be clearly separated and identified. As a result, by comparing the absorption value of 280 nm of the absorption maximum of PVP and the absorption value of 235 nm of the absorption maximum of TPS with a calibration curve obtained in advance, the resin base material and the photoacid generator ( The concentration or composition ratio of (PAG) can be easily measured.
[0018]
【The invention's effect】
As explained above, the composition ratio of materials that were difficult to separate and identify because of near ultraviolet absorption can be easily identified in the state of a mixed solution, so that the high quality of resist materials can be maintained, and if applied to mass production of semiconductor devices, There is an effect that a precise pattern can be drawn accurately.
[Brief description of the drawings]
FIG. 1 is a block diagram of a measuring apparatus according to an embodiment of the present invention.
1 is a resist,
2 is solvent,
3 is a pump,
4 is a pre-column,
5 is a GPC column,
6 is an ultraviolet spectrometer (photodiode array detector),
7 is a data processing device,
8 is a waste liquid.

Claims (2)

  For UV-sensitive chemically amplified resists that contain both a photoacid generator and a resin base material, molecular weight fractionation by the GPC (gel permeation chromatography) method and UV absorption / transmittance measurement are sequentially performed. A method for producing an ultraviolet-sensitive chemically amplified resist, comprising a step of sorting out only a homogeneous chemically amplified resist based on a composition ratio obtained from the molecular weight fractionation result and the ultraviolet absorption rate or transmittance measurement result. For UV-sensitive chemically amplified resists that contain both a photoacid generator and a resin base material, molecular weight fractionation by the GPC (gel permeation chromatography) method and UV absorption / transmittance measurement are sequentially performed. performed, the molecular weight fractionation results and testing method of UV-sensitive chemically amplified resist comprising a step of obtaining the ultraviolet absorptivity or transmittance measurements or al sets composition ratio.

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