August 21, 2009
`
`Re: 6319-122637
`
`To Whom It May Concern:
`
`This is to certify that a professional translator on our staff who is skilled in the Japanese language
`translated “JP04071222A” from Japanese into English.
`
`We certify that the English translation conforms essentially to the original Japanese language.
`
`
`
`
`Kim Vitray
`Operations Manager
`
`Subscribed and sworn to before me this 21st day of August, 2009.
`
`
`
`
`
`
`Vicki Wunneburger
`Notary Public
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`
`VNM=tÉëí=^îÉåìÉI==^ìëíáåI=qÉñ~ë=TUTMN=rp^I==+N=RNOJQTOJSTRPI==UMMJRPNJVVTTI==c^u=+N=RNOJQTOJQRVN
`
`SAMSUNG-1005.001
`
`

`
`Japanese Kokai Patent Application No. Hei 4[1992]-71222
`
`Job No.: 6319-122637
`Translated from Japanese by the McElroy Translation Company
`800-531-9977
`customerservice@mcelroytranslation.com
`
`Ref.: JP04071222A
`
`SAMSUNG-1005.002
`
`

`
`1
`
`(19) JAPANESE PATENT OFFICE
`(JP)
`(12) KOKAI TOKUHYO PATENT
`GAZETTE (A)
`
`(11) PATENT APPLICATION
`KOKAI PUBLICATION
`NO. HEI 4[1992]-71222
`(43) Publication Date: March 5, 1992
`
`(51) Int. Cl.5:
`H 01 L 21/027
`G 03 F 7/26
`7/40
`
`Identification Codes:
`511
`
`Sequence Nos. for
`Office Use:
`7124-2H
`7124-2H
`7352-4M
`7352-4M
`
`(54) Title
`
`Examination Request: Not filed
`PATTERN FORMING METHOD
`
`H 01 L 21/30
`
`361 S
`361 P
`
`No. of Claims: 2 (Total of 5 pages)
`
`(21) Filing No.:
`(22) Filing Date:
`
`Hei 2[1990]-184447
`July 12, 1990
`
`(72) Inventors: Hideyuki Jinbo
`(72)
`Yoshiyuki Kawazu
`(72)
`Yoshio Yamashita
`(71) Applicant:
`(74) Agent:
`
`Oki Electric Industry Co., Ltd., 1-7-12 Toranomon, Minato-ku, Tokyo
`Oki Electric Industry Co., Ltd., 1-7-12 Toranomon, Minato-ku, Tokyo
`Oki Electric Industry Co., Ltd., 1-7-12 Toranomon, Minato-ku, Tokyo
`Oki Electric Industry Co., Ltd., 1-7-12 Toranomon, Minato-ku, Tokyo
`Takashi Ohgaki, patent attorney
`
`Claims
`
`1. A pattern forming method characterized in comprising:
`a process to form a first resist on a substrate and to pattern said first resist,
`a process to insolubilize the first resist pattern obtained with the aforementioned pattern
`relative to the solvent for a second resist formed later on the aforementioned substrate having
`said first resist pattern and to the developer used later for developing said second resist,
`performed,
`and a process to form said second resist on the aforementioned substrate having said first
`resist pattern which has been insolubilized and to pattern said second resist.
`2. The pattern forming method described in Claim 1, characterized in that the
`abovementioned insolubilizing treatment is performed by placing the substrate having the
`aforementioned first resist pattern in a gas plasma that contains a fluorine compound gas in
`which the hydrogen in an alkane has been replaced with fluorine,
`
`SAMSUNG-1005.003
`
`

`
`2
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`Detailed explanation of the invention
`Industrial application field
`The present invention relates to a pattern forming method used in the process of
`manufacturing semiconductor devices or the like.
`
`Prior art
`Projection exposure apparatuses are widely used to manufacture IC, LSI and other
`semiconductor devices.
`In the past, when a resist pattern has been formed using a projection exposure apparatus,
`the procedure generally used has been to coat a substrate, such as a silicon wafer, with a resist,
`expose the resist with the projection exposure apparatus, and then develop the resist and obtain
`the final resist pattern.
`The resolving power R (critical dimensions at which line and space dimensions can be
`resolved to be equal to each other) of the projection exposure apparatus in a process such as this
`is given by Equation 1 below.
`
`Here, k is a constant and is usually around 0.6, but this is a value that varies somewhat
`according to the process.  is the wavelength of the exposure light, and NA is the numerical
`aperture of the projection exposure apparatus projection lens.
`Therefore, in order to obtain the highest resolving power possible to handle
`miniaturization in semiconductor device design rules, exposure light wavelengths have been
`shortened and projection lens NA has been made higher.
`Projection exposure apparatuses with higher NA that are currently available include those
`using exposure light of g rays (436 nm) and with NA of 0.54, and those using exposure light of
`i rays (365 nm) and with NA of 0.45.
`Concerning the resolution of these projection exposure apparatuses, letting k in
`abovementioned Equation (1) be 0.6, the resolving power R1 of the former will be
`
`and resolving power R2 of the latter will be
`
`That is, these projection exposure apparatuses are capable of patterning at about 0.5 m, and the
`manufacture of 16 Mbit DRAMs and the like is possible.
`
`SAMSUNG-1005.004
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`

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`3
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`Problems to be solved by the invention
`However, there are limits to increasing the NA of the projection exposure apparatus
`projection lens due to the difficulty of lens manufacture. In concrete terms, NA is 0.65 for those
`for g rays, and for i rays it is 0.60. With those for KrF excimer lasers (248 nm wavelength), 0.5 is
`about the limit. Therefore, the resolving power under these conditions will be 0.4, 0.36, and
`0.30 m, respectively, in accordance with Equation 1 (assuming k = 0.6). For this reason, with
`pattern formation using conventional pattern forming methods using these exposure apparatuses
`(methods in which a resist is exposed and then developed to obtain the final resist pattern),
`pattern formation for design rules of 0.25 m or less has been difficult.
`This invention was devised taking these points into consideration. Therefore, the
`objective of this invention is to provide a pattern forming method with which resist patterns
`below the resolution limit of the projection exposure apparatus can be formed.
`
`Means to solve the problems
`In order to accomplish this objective, the pattern forming method of the present invention
`is characterized in comprising:
`a process to form a first resist on a substrate and to pattern said first resist,
`a process to insolubilize the first resist pattern obtained with the aforementioned pattern
`relative to the solvent for a second resist formed later on the aforementioned substrate having
`said first resist pattern and to the developer used later for developing said second resist,
`and a process to form said second resist on the aforementioned substrate having said first
`resist pattern which has been insolubilized and to pattern said second resist.
`To implement this invention, it is ideal to perform the abovementioned insolubilizing
`treatment by placing the substrate having the abovementioned first resist in a plasma containing a
`fluorine compound gas in which the hydrogen in an alkane has been replaced with fluorine.
`Note that the substrate referred to here is, for example, a glass substrate, a silicon
`substrate, a GaAs substrate or other type of substrate, or an insulating film on the substrate, a
`metal film or other thin film, and/or an intermediate body in which elements are constructed.
`
`Operation
`With the construction of this invention, a first resist pattern and a second resist pattern are
`arranged in a prescribed relationship on a substrate (for example, a space of the second resist
`pattern is arranged in an area corresponding to a space section of the first resist pattern on the
`substrate) for forming resist patterns, and the patterns can become the final resist pattern.
`Therefore, even through both the first resist pattern and the second resist pattern are patterns with
`dimensions within the resolution limits of the projection exposure apparatus used, the final resist
`
`SAMSUNG-1005.005
`
`

`
`4
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`pattern will be a pattern with minute dimensions beyond the resolution limits of said projection
`exposure apparatus.
`
`Application example
`An application example of the pattern forming method of this invention is explained
`below with reference to the figures. Note that the apparatus used, the materials used, and
`quantified conditions such as time, temperature and film thickness discussed in the explanation
`below are no more than ideal examples within the scope of this invention. It should therefore be
`understood that this invention is not limited to only these conditions.
`
`Application example
`First, a pattern forming method in an application example is explained with reference to
`Figures 1 (A)-(E). Note that Figures 1 (A)-(E) are process diagrams of samples in the principal
`processes showing them sectioned in a direction perpendicular to the principal surface of a
`substrate 11.
`First, with this application example, a silicon oxide film (not shown) 3000 Å thick is
`formed with a known method on a silicon substrate 3 inches (1 inch is about 2.54 cm) in
`diameter. Part of the silicon oxide film is additionally removed using known photolithography
`technology and etching technology to form alignment marks (not shown) for the projection
`exposure apparatus, producing substrate 11 of the application example (Figure 1 (A)).
`Next, TSMR-365iR (positive resist for i rays made by Tokyo Ohka Kogyo Co. (Ltd.)) is
`formed, in this application example to a thickness of 1 m, as first resist 13 on substrate 11 using
`spin coating (Figure 1 (B)).
`Next, the sample is baked for 90 sec at a temperature of 90ºC using a hot plate.
`Next, using an i ray projection exposure apparatus RA-101VLII (NA = 0.42: made by
`Hitachi (Ltd.)) on which is mounted a mask having a line and space pattern with which spaces
`0.4 m wide can be formed at a pitch of 1.2 m on a resist, the mask alignment marks and the
`substrate alignment marks are positioned, and then first resist 13 is exposed with exposure light
`of 300 mJ/cm2.
`Next, the exposed first resist 13 is puddle-developed for 60 sec using a developer called
`NMD-W (2.38% tetramethylammonium hydroxide aqueous solution: made by Tokyo Ohka
`Kogyo Co. (Ltd.)), and first resist pattern 13a is obtained (Figure 1 (B)).
`When the first resist pattern 13a obtained was observed using an SEM dimension
`measuring machine (S-6000 made by Hitachi (Ltd.)), it was seen that a finished pattern wherein
`the space width was 0.3 m and pitch was 1.2 m (that is, spaces are 0.9 m) was accomplished.
`
`SAMSUNG-1005.006
`
`

`
`5
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`Next, substrate 11 having first resist pattern 13a is mounted in the reaction chamber of a
`parallel flat dry etching apparatus DEM451 made by Nichiden Anelva (Ltd.).
`Next, oxygen gas and CF4 gas, as a fluorine compound gas in which in this case the
`hydrogen in an alkane has been replaced with fluorine, are each supplied at a rate of 10 sccm into
`the reaction furnace [sic], and a plasma of the aforementioned mixed gas is generated in the
`reaction furnace with the pressure of the mixed gas at 50 mTorr and RF power at 0.01 W/cm2.
`By leaving first resist pattern 13a in such a gas plasma, first resist pattern 13a will demonstrate
`insolubility relative to the solvent and developer for the second resist, discussed below, and a
`first resist pattern 13b that has been insolubilized is obtained (Figure 1 (C)). Note that substrate
`11 having first resist pattern 13a is left in the reaction furnace for 1 min in this application
`example.
`Next, substrate 11 having first resist pattern 13b which has been insolubilized is spin-
`coated to a thickness of 1.0 m with TSMR-365iR, used as the first resist in this case, as second
`resist 15 (Figure 1 (D)).
`First resist pattern 13b which has been insolubilized has been treated as described above
`to be insoluble relative to a solvent for second resist 15, so that even though first resist pattern
`13b is covered by second resist 15, no destruction of the first resist pattern itself occurs, and no
`mixing with the second resist occurs either.
`Next, second resist 15 is baked under the same conditions as those for the first resist.
`Next, substrate 11 having the second resist which has been baked is placed on the wafer
`stage of the projection exposure apparatus used previously. Then substrate 11 is aligned with a
`mask which has been mounted in the projection exposure apparatus. Next the wafer stage is
`shifted 0.3 m in the x direction, that is, the wafer stage is shifted so that the spaces of the mask
`will be projected on the spaces of first resist pattern 13b which has been insolubilized. Then
`second resist 15 is exposed with exposure light of 300 mJ/cm2.
`Next, the second resist which has been exposed is developed under the same conditions
`as those for the first resist, and a second resist pattern 15a is obtained (Figure 1 (E)). Note that
`first resist pattern 13b which has been insolubilized has been treated as described above to be
`insoluble relative to the developer NMD-W, so that no destruction of the pattern occurred during
`developing of the second resist.
`After second resist developing, a resist pattern 17 constructed with first resist pattern 13b,
`which has been insolubilized, and second resist pattern 15a is formed on substrate 11 (Figure 1
`(E)). When resist pattern 17 was observed with an S-6000 SEM length measuring machine, it
`was seen that a pattern in which spaces 0.3 m wide are aligned at a pitch of 0.6 m, that is, a
`0.3 m line and space pattern, was resolved.
`
`SAMSUNG-1005.007
`
`

`
`6
`
`Comparative example
`The same substrate used in the application example was coated to the same thickness
`using the same method and the same TSMR-365iR resist as were used in the application example,
`and the resist was baked under the same conditions as the application example. Next, using test
`masks having various line and space patterns, the resist pattern was exposed with the same
`amount of exposure light and using the same projection exposure apparatus as in the application
`example, and was additionally developed with the same method as the application example
`(comparative example pattern forming method = conventional ordinary pattern forming method).
`With the comparative example pattern forming method, the smallest pattern is a pattern
`having 0.4 m spaces at a pitch of 0.8 µm, that is, a 0.4 m line and space pattern, and it was
`seen that a 0.3 m line and space pattern was absolutely not resolved.
`As is clear from the explanations of the comparative example and the application
`example, it can be seen that, with a system using TSMR-365-iR resist and an RA-101VLII
`projection exposure apparatus, when the resolution limit is 0.4 m, a 0.3 m line and space
`pattern, which exceeds the resolution limit of the system, can be obtained by applying the pattern
`forming method of this invention to the system.
`The present application example represents an experiment using the RA-101VLII that
`was only performed based on the availability of the projection exposure apparatus. It can
`therefore, be seen that if a projection exposure apparatus with a higher resolution limit than the
`RA-101VLII is used and the pattern forming method of this invention is applied, pattern
`formation according to the 0.25 m rule or less, which has not been obtained with existing
`projection exposure apparatuses, will be possible.
`In the above, an application example of the pattern forming method of this invention was
`explained, but this invention is not limited to only the abovementioned application example, and
`modifications as mentioned below can be added.
`For example, with the abovementioned application example, the resist used was TSMR-
`365iR, but the resists that can be used for this invention are not limited to this and could be
`others (either negative or positive). However, when an insolubilizing treatment is performed
`using a gas plasma containing a fluorine compound gas in which the hydrogen in an alkane has
`been replaced by fluorine, it is ideal for the resist to be a so-called novolak resist (either positive
`or negative). This is because the effects of the insolubilizing treatment will be very effectively
`obtained.
`The first resist insolubilizing treatment method is also not limited to the method in the
`application example, and could be another method.
`Also, with the abovementioned application example, the same resist was used for both
`the first resist and the second resist, but the two could also be different resists, as necessary.
`
`SAMSUNG-1005.008
`
`

`
`7
`
`It is also satisfactory, of course, to implement this invention so that after formation of the
`second resist pattern, it is insolubilized relative to the solvent and developer for a third resist, and
`then a third resist pattern is formed, as necessary.
`
`Effect of the invention
`As is evident from the explanation above, with the pattern forming method of this
`invention, a first resist pattern is formed on a substrate, and then the next resist pattern can be
`formed in areas in the first resist pattern spaces on the substrate. Thus a minute resist pattern
`exceeding the resolution limit of the exposure apparatus (below the resolution limit) can be
`formed.
`Therefore, the pattern forming method of this invention makes the manufacture of highly
`integrated SI or the like easy.
`
`Brief description of the figures
`Figures 1 (A)-(E) are process diagrams provided to explain the pattern forming method in
`the application example.
`
`11
`13
`13a
`13b
`15
`15a
`17
`
`Substrate
`First resist
`First resist pattern
`First resist pattern which has been insolubilized
`Second resist
`Second resist pattern
`Resist pattern
`
`SAMSUNG-1005.009
`
`

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`8
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`Figure 1. Process diagrams provided to explain the pattern forming method of this invention
`
`Legend: 11 Substrate
`13 First resist
`13a First resist pattern
`13b First resist pattern which has been insolubilized
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`SAMSUNG-1005.010
`
`

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`9
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`Figure 1. Process diagrams provided to explain the pattern forming method of this invention
`
`Legend: 15 Second resist
`15a Second resist pattern
`17 Resist pattern
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`SAMSUNG-1005.011