TW202138907A

TW202138907A - Photomask

Info

Publication number: TW202138907A
Application number: TW109145883A
Authority: TW
Inventors: 田中千惠; 山田步實; 齊藤隆史
Original assignee: 日商Ｓｋ電子股份有限公司
Priority date: 2020-01-07
Filing date: 2020-12-24
Publication date: 2021-10-16
Also published as: KR102555946B1; TWI770736B; CN113156758A; KR20210089086A; JP2021110770A; JP7383490B2

Abstract

The present invention provides a photomask capable of stably resolving fine hole patterns. This photomask includes: a transmissive part exposing the transmissive substrate; and a first phase shift part and a second phase shift part surrounding the transmissive part and inverting the phase of exposure light. The second phase shift part is interposed between the first phase shift part and the transmission part. The transmittance of the second phase shift part to exposure light is lower than the transmittance of the first phase shift part. In addition, the second phase shift part can be constituted by a laminated structure of the phase shift film and the semi-permeable film of the first phase shift part.

Description

光掩模Photomask

本發明涉及一種在光刻工序中所使用的光掩模。The present invention relates to a photomask used in a photolithography process.

在用於製造平板顯示器等電子設備的光刻工序中使用光掩模。一直以來，用於將孔圖案轉印至光致抗蝕劑的光掩模使用的是具備遮光部和透過部、幷且與孔圖案對應的部位成爲透過部的二元掩模。近年來，例如，爲了能够形成2[μm]以下的微細的孔圖案，提出了相移掩模作爲用於孔的圖案化的光掩模。已知相移掩模與以往的二元掩模相比不僅具有分辨率的提高效果，而且還具有焦深（DOF）的改善效果。（例如參照專利文獻1的第4段落）先前技術文獻專利文獻A photomask is used in a photolithography process used to manufacture electronic devices such as flat panel displays. Conventionally, a photomask for transferring a hole pattern to a photoresist has used a binary mask having a light-shielding portion and a transmission portion, and a portion corresponding to the hole pattern becomes a transmission portion. In recent years, for example, in order to be able to form a fine hole pattern of 2 [μm] or less, a phase shift mask has been proposed as a photomask for hole patterning. Compared with conventional binary masks, it is known that the phase shift mask not only has the effect of improving the resolution, but also has the effect of improving the depth of focus (DOF). (For example, refer to paragraph 4 of Patent Document 1) Prior art literature Patent literature

專利文獻1：日本特開2018-163335號公報Patent Document 1: Japanese Patent Application Publication No. 2018-163335

發明要解決的課題The problem to be solved by the invention

但是，在使用相移掩模而將微細的孔圖案轉印至光致抗蝕劑的情況下，雖然可得到焦深的提高效果，但是需要高曝光量（Dose）。因此，具有曝光時間增大、曝光裝置的節拍時間增大的問題。However, when a phase shift mask is used to transfer a fine hole pattern to a photoresist, although the effect of improving the depth of focus can be obtained, a high exposure amount (Dose) is required. Therefore, there is a problem that the exposure time increases and the tact time of the exposure device increases.

鑒於上述課題，本發明的目的在於提供能够穩定地解像微細的孔圖案的光掩模。用於解決課題的手段In view of the above-mentioned problems, an object of the present invention is to provide a photomask capable of stably resolving fine hole patterns. Means to solve the problem

本發明涉及的光掩模，其特徵在於，其具備透過部、第1相移部和第2相移部，所述第1相移部及第2相移部包圍所述透過部，所述第2相移部介於所述第1相移部與所述透過部之間，所述第2相移部及所述第1相移部將曝光光的相位反轉，所述第2相移部的透射率比所述第1相移部的透射率低。The photomask according to the present invention is characterized in that it includes a transmission portion, a first phase shift portion, and a second phase shift portion, The first phase shift part and the second phase shift part surround the transmission part, The second phase shift part is interposed between the first phase shift part and the transmission part, The second phase shift part and the first phase shift part invert the phase of the exposure light, The transmittance of the second phase shift part is lower than the transmittance of the first phase shift part.

另外，本發明涉及的光掩模，其特徵在於，所述第1相移部的透射率爲8～15%，所述第2相移部的透射率爲3～7%。In addition, the photomask according to the present invention is characterized in that the transmittance of the first phase shift portion is 8 to 15%, and the transmittance of the second phase shift portion is 3 to 7%.

另外，本發明涉及的光掩模，其特徵在於，所述第1相移部及所述第2相移部的相移量爲160[°]以上且210[°]以下的範圍。In addition, the photomask according to the present invention is characterized in that the amount of phase shift of the first phase shift portion and the second phase shift portion is in a range of 160 [°] or more and 210 [°] or less.

通過設爲這樣的構成，從而可以提供能够改善光刻工序中的DOF及所需曝光量的光掩模。By adopting such a configuration, it is possible to provide a photomask that can improve the DOF in the photolithography process and the required amount of exposure.

另外，本發明涉及的光掩模，其特徵在於，所述第1相移部的相移量爲160[°]以上且190[°]以下的範圍，所述第2相移部的相移量爲180[°]以上且210[°]以下的範圍。In addition, the photomask according to the present invention is characterized in that the phase shift amount of the first phase shift part is in the range of 160 [°] or more and 190 [°] or less, and the phase shift of the second phase shift part The amount is in the range of 180 [°] or more and 210 [°] or less.

通過設爲這樣的構成，從而容易調整第1相移部及第2相移部的相移量。By adopting such a configuration, it is easy to adjust the phase shift amount of the first phase shift part and the second phase shift part.

另外，本發明涉及的光掩模，其特徵在於，所述第2相移部是構成所述第1相移部的相移膜與半透過膜的層疊。In addition, the photomask according to the present invention is characterized in that the second phase shift portion is a stack of a phase shift film and a semi-permeable film constituting the first phase shift portion.

通過設爲這樣的構成，從而容易製造光掩模。發明效果By adopting such a configuration, it is easy to manufacture a photomask. Invention effect

根據本發明，可以提供能够穩定地解像微細的孔圖案的光掩模。According to the present invention, it is possible to provide a photomask capable of stably resolving a fine hole pattern.

以下，參照附圖對本發明的實施方式進行說明。但是，以下的實施方式均不在本發明的主旨的認定中給出限定性的解釋。另外，有時對相同或同種構件標注相同的參照符號而省略說明。Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments do not give a limited interpretation in determining the gist of the present invention. In addition, the same reference signs may be attached to the same or the same kind of members, and the description may be omitted.

（實施方式1）圖1（a）是表示本發明涉及的光掩模100的俯視圖，圖1（b）、圖1（c）是就對光致抗蝕劑進行曝光時的DOF及所需曝光量來說明本光掩模100的改善效果的圖表。通過將光掩模100用於光刻工序，從而能够將微細孔（尤其是1.5[μm]～2.0[μm]的尺寸）穩定地解像到作爲曝光對象的光致抗蝕劑上。(Embodiment 1) Fig. 1(a) is a plan view showing the photomask 100 according to the present invention. Fig. 1(b) and Fig. 1(c) illustrate the DOF and required exposure amount when exposing the photoresist. A graph of the improvement effect of the photomask 100. By using the photomask 100 in the photolithography process, the micropores (especially, the size of 1.5 [μm] to 2.0 [μm]) can be stably resolved to the photoresist that is the object of exposure.

光掩模100以包圍用於在抗蝕劑上形成孔圖案的透過部101的方式形成第1相移部102，第2相移部（凸緣（外緣）部）103介於透過部101（開口部）與第1相移部102之間。因此，透過部101與第2相移部103相接，第2相移部103與第1相移部102相接。第1相移部102及第2相移部103具有能够將用於製造電子設備的光刻工序中所使用的曝光光反轉的相移量。The photomask 100 forms the first phase shift portion 102 so as to surround the transmission portion 101 for forming a hole pattern in the resist, and the second phase shift portion (flange (outer edge) portion) 103 is interposed between the transmission portion 101 (Opening portion) and the first phase shift portion 102. Therefore, the transmission part 101 is in contact with the second phase shifting part 103, and the second phase shifting part 103 is in contact with the first phase shifting part 102. The first phase shift unit 102 and the second phase shift unit 103 have a phase shift amount capable of inverting the exposure light used in the photolithography process for manufacturing the electronic device.

相當於透過部101（開口部）與第1相移部102的相對距離的、第2相移部的寬度R（參照圖1）爲0[μm]＜R≤1[μm]，更優選爲0.5[μm]≤R≤1[μm]。與第1相移部102相比，第2相移部（凸緣部）103對曝光光的透射率較低。即，以依次包圍孔開口用圖案的透過部101的周圍的方式來形成低透射率的相移部（第2相移部103）及高透射率的相移部（第1相移部102）。The width R (see FIG. 1) of the second phase shift portion corresponding to the relative distance between the transmissive portion 101 (opening portion) and the first phase shift portion 102 is 0 [μm] <R ≤ 1 [μm], more preferably 0.5[μm]≤R≤1[μm]. Compared with the first phase shift portion 102, the second phase shift portion (flange portion) 103 has a lower transmittance of exposure light. That is, a low-transmittance phase shift portion (second phase shift portion 103) and a high-transmittance phase shift portion (first phase shift portion 102) are formed so as to sequentially surround the periphery of the transmissive portion 101 of the hole opening pattern. .

透過部101對光刻工序中的曝光光（i射綫）的透射率爲90～100%（90%≤透射率≤100%），取決於光掩模的透過性基板。第1相移部102相對於曝光光（i射綫）的相移量（相位差）爲大致180[°]，透射率爲8～15%（8%≤透射率≤15%）。第2相移部103相對於曝光光（i射綫）的相移量爲大致180[°]，透射率爲3～7%（3%≤透射率≤7%）。如上所述，第1相移部102及第2相移部103均爲大致180[°]（具體而言爲160[°]≤相移量≤210[°]）而將曝光光的相位反轉。另外，第2相移部103的透射率比第1相移部102的透射率低。予以說明，如後所述，例如在第1相移部102由單層結構構成、且第2相移部103由層疊結構構成的情況下，第1相移部102及第2相移部103的相移量可以分別設爲例如160[°]≤相移量≤190[°]及180[°]≤相移量≤210[°]。通過設定這些相移量的規格，從而容易調整第1相移部102及第2相移部103的相移量，幷且也容易製造光掩模。The transmittance of the transparent portion 101 to the exposure light (i-ray) in the photolithography process is 90 to 100% (90%≦transmittance≦100%), depending on the transparent substrate of the photomask. The phase shift amount (phase difference) of the first phase shift unit 102 with respect to the exposure light (i-ray) is approximately 180 [°], and the transmittance is 8 to 15% (8%≦transmittance≦15%). The phase shift amount of the second phase shift unit 103 with respect to the exposure light (i-ray) is approximately 180 [°], and the transmittance is 3 to 7% (3%≦transmittance≦7%). As described above, the first phase shift unit 102 and the second phase shift unit 103 are both approximately 180 [°] (specifically, 160 [°] ≤ phase shift amount ≤ 210 [°]), and reverse the phase of the exposure light. change. In addition, the transmittance of the second phase shift portion 103 is lower than the transmittance of the first phase shift portion 102. It should be noted that, as will be described later, for example, in the case where the first phase shifting section 102 is composed of a single-layer structure and the second phase shifting section 103 is composed of a laminated structure, the first phase shifting section 102 and the second phase shifting section 103 The phase shift amount of can be set to, for example, 160[°]≦phase shift amount≦190[°] and 180[°]≦phase shift amount≦210[°], respectively. By setting the specifications of these phase shift amounts, it is easy to adjust the phase shift amounts of the first phase shift portion 102 and the second phase shift portion 103, and it is also easy to manufacture a photomask.

製造具有微細圖案的LSI的半導體工藝的DOF要求值最多爲1[μm]左右，與此相比，在對平板顯示器等電子設備的光刻工序中，例如在穩定地轉印尺寸2.0[μm]以下的孔的圖案的情況下，要求DOF比半導體工藝的DOF值高10倍以上。根據本發明，確認到能够滿足這樣的苛刻條件，進而確認到相比於專利文獻1所公開的最小所需曝光量（EOP）得到進一步的降低效果。另外，對第2相移部103的寬度R進行了調查，結果確認到特別優選的寬度R爲0.5～1.0[μm]。The required DOF value of the semiconductor process for manufacturing LSIs with fine patterns is about 1 [μm] at most. Compared with this, in the photolithography process for flat panel displays and other electronic devices, for example, the transfer size is stably 2.0 [μm]. In the case of the following hole patterns, the DOF is required to be 10 times or more higher than the DOF value of the semiconductor process. According to the present invention, it has been confirmed that such severe conditions can be satisfied, and it has been confirmed that the minimum required exposure amount (EOP) disclosed in Patent Document 1 has a further reduction effect. In addition, the width R of the second phase shift portion 103 was investigated, and as a result, it was confirmed that the particularly preferable width R was 0.5 to 1.0 [μm].

將DOF及EOP的改善效果示於圖1（b）、圖1（c）中。圖1（b）、圖1（c）是表示在光致抗蝕劑膜上與掩模上的S（邊的長度）大致同等尺寸地形成2[μm]尺寸的孔圖案時的DOF和所需曝光量（EOP）的條件依賴性的圖表。圖1（b）、圖1（c）的圖表的縱軸的“DOF”及“EOP”分別表示相對於由透過部和遮光部形成的以往的二元掩模的DOF及EOP而言的比值。在圖1（b）、圖1（c）中，“PS”是指使用了對曝光光（i射綫）的透射率爲5%的單層（不具有第2相移部103）相移膜的光掩模。“PS+PS-Rim”是指具備高透射率的第1相移部102和低透射率的第2相移部103的光掩模，第1相移部102的透射率爲12%，第2相移部103的透射率爲5%。予以說明，相移量均爲180[°]。The improvement effects of DOF and EOP are shown in Figure 1(b) and Figure 1(c). Figures 1(b) and 1(c) show the DOF and the position when a hole pattern of 2 [μm] is formed on the photoresist film with approximately the same size as the S (side length) on the mask. A graph of the conditional dependence of required exposure (EOP). The "DOF" and "EOP" on the vertical axis of the graphs of Fig. 1(b) and Fig. 1(c) respectively indicate the ratios of DOF and EOP to the conventional binary mask formed by the transmissive part and the light-shielding part . In Figure 1 (b) and Figure 1 (c), "PS" refers to the use of a single layer (without the second phase shift part 103) with a transmittance of 5% to the exposure light (i-ray) Film photomask. "PS+PS-Rim" refers to a photomask having a first phase shift portion 102 with high transmittance and a second phase shift portion 103 with low transmittance. The transmittance of the first phase shift portion 102 is 12%. The transmittance of the 2 phase shift part 103 is 5%. It should be noted that the phase shift amounts are all 180 [°].

在“PS”的情況下，與以往的二元掩模相比，DOF增大至約1.5倍，確認到改善效果，但是存在EOP增加至1.3倍的問題。在“PS+PS-Rim”的情況下，确认到DOF与以往的二元掩模相比增加至约1.9倍，即便与“PS”相比，也具有進一步的改善效果。另一方面，EOP爲約1.1倍，與以往的二元掩模爲同等程度。即，通過具備第1相移部102和第2相移部103的光掩模，確認到既抑制（減輕）所需曝光量的增大，又得到DOF的大幅改善效果。In the case of "PS", the DOF was increased by about 1.5 times compared with the conventional binary mask, and the improvement effect was confirmed, but there was a problem that the EOP was increased by 1.3 times. In the case of "PS+PS-Rim", it was confirmed that the DOF was increased by about 1.9 times compared with the conventional binary mask, and even compared with the "PS", it has a further improvement effect. On the other hand, the EOP is approximately 1.1 times, which is equivalent to the conventional binary mask. That is, it was confirmed that the photomask provided with the first phase shift portion 102 and the second phase shift portion 103 not only suppressed (reduces) an increase in the required exposure amount, but also obtained a significant improvement effect of DOF.

另外，通過將第2相移部103的透射率設爲5%，幷且在8～15%的範圍增加第1相移部102的透射率，確認到DOF具有增加的傾向，EOP幾乎沒有變化（反而稍微減少）。因此，具有對透射率而言的餘量（margin）（例如對光掩模的面內透射率的均勻性而言的餘量），能够實現穩定的曝光條件。予以說明，上述的傾向在第2相移部103的透射率爲3～7%的範圍時也同樣。另一方面，在僅使用了不具備低透射率的第2相移部103的單層相移膜的相移掩模的情況下，確認到EOP對於相移膜的透射率的依賴性高，容易因相移膜的透射率發生變動而受到影響。In addition, by setting the transmittance of the second phase shift portion 103 to 5%, and increasing the transmittance of the first phase shift portion 102 in the range of 8 to 15%, it was confirmed that the DOF tended to increase, and EOP hardly changed. (Instead, it decreases slightly). Therefore, there is a margin for the transmittance (for example, a margin for the uniformity of the in-plane transmittance of the photomask), and stable exposure conditions can be realized. In addition, the above-mentioned tendency is the same also when the transmittance|permeability of the 2nd phase shift part 103 is 3-7%. On the other hand, in the case of a phase shift mask using only a single-layer phase shift film that does not have the second phase shift portion 103 with low transmittance, it was confirmed that EOP has a high dependence on the transmittance of the phase shift film. It is easily affected by changes in the transmittance of the phase shift film.

這樣，光掩模100具有充分高的DOF，對抗蝕劑的膜厚而言可確保充分的光刻工藝的餘量。進而還能抑制孔開口所需的曝光量的增大。因此，可以滿足製造電子設備時對光刻工序的要求而在抗蝕劑膜上穩定地形成孔圖案。In this way, the photomask 100 has a sufficiently high DOF, and a sufficient margin for the photolithography process can be ensured for the film thickness of the resist. Furthermore, it is possible to suppress an increase in the amount of exposure required for the hole opening. Therefore, it is possible to stably form a hole pattern in the resist film while meeting the requirements for the photolithography process when manufacturing electronic devices.

予以說明，雖然對曝光光爲i射綫的情況進行了說明，但是曝光光幷不限定於i射綫，可以爲i射綫、h射綫及g射綫或它們的混合光。相移量、透射率可以對應於曝光光的代表波長來設定。予以說明，在其他實施方式中也同樣。Incidentally, although the case where the exposure light is i-rays has been described, the exposure light is not limited to i-rays, and may be i-rays, h-rays, g-rays, or their mixed light. The amount of phase shift and transmittance can be set according to the representative wavelength of the exposure light. It should be noted that the same applies to other embodiments.

以下，詳細地說明本實施方式的光掩模100的製造工序。如圖2（a）所示，準備合成石英玻璃等透過性基板1，利用濺射法、蒸鍍法等在透過性基板1上形成（例如膜厚5[nm]～20[nm]）由例如Cr系金屬化合物等形成的半透過膜2（半色調膜）。此時，半透過膜2對曝光光（i射綫）的透射率例如通過調整組成及膜厚而設定成40～70%。Hereinafter, the manufacturing process of the photomask 100 of this embodiment is demonstrated in detail. As shown in Figure 2(a), a transparent substrate 1 such as synthetic quartz glass is prepared and formed on the transparent substrate 1 by sputtering, vapor deposition, etc. (for example, a film thickness of 5 [nm] to 20 [nm]) For example, a semi-permeable film 2 (halftone film) formed of a Cr-based metal compound or the like. At this time, the transmittance of the semi-transmissive film 2 to exposure light (i-ray) is set to 40 to 70% by adjusting the composition and film thickness, for example.

接著，如圖2（b）所示，在半透過膜2上形成（光刻）抗蝕劑膜，利用曝光及顯影工藝將抗蝕劑膜圖案化。之後，以圖案化的抗蝕劑膜作爲掩模，利用濕蝕刻法或幹蝕刻法將半透過膜2進行蝕刻，形成由半透過膜2形成的圖案3。之後，通過灰化法或浸漬於抗蝕劑剝離液來除去抗蝕劑膜。圖案3的截面的寬度設定爲圖1（a）的第2相移部的寬度R。予以說明，爲了後續的光刻，也可以將半透過膜2圖案化而適當形成對準標記。Next, as shown in FIG. 2(b), a resist film (photolithography) is formed on the semi-permeable film 2, and the resist film is patterned by exposure and development processes. After that, using the patterned resist film as a mask, the semi-permeable film 2 is etched by a wet etching method or a dry etching method to form a pattern 3 formed of the semi-permeable film 2. After that, the resist film is removed by an ashing method or immersion in a resist stripping solution. The width of the cross section of the pattern 3 is set to the width R of the second phase shift portion in FIG. 1( a ). In addition, for subsequent photolithography, the semi-transmitting film 2 may be patterned to form an alignment mark as appropriate.

圖2（c）是圖2（b）所示工序中的光掩模100的俯視圖，其表示圖案3的輪廓（layout）。圖案3以包圍用於形成孔圖案的開口部4的周圍的凸緣部（外邊緣部）的形式來形成。例如在將2.0[μm]的孔圖案轉印至光致抗蝕劑膜的情況下，光掩模100的開口部4的優選尺寸S（邊的長度）爲2.2～2.4[μm]。FIG. 2(c) is a plan view of the photomask 100 in the process shown in FIG. 2(b), which shows the outline of the pattern 3 (layout). The pattern 3 is formed in the form of a flange part (outer edge part) surrounding the opening part 4 for forming a hole pattern. For example, in the case of transferring a 2.0 [μm] hole pattern to a photoresist film, the preferred size S (side length) of the opening 4 of the photomask 100 is 2.2 to 2.4 [μm].

接著，如圖3（a）所示，利用濺射法、蒸鍍法等形成（例如膜厚50[nm]～100[nm]）由例如Cr系金屬化合物等形成的相移膜5（相位反轉膜）。調整組成及膜厚，以使相移膜5對曝光光（i射綫）的透射率爲8～15%、相移量爲160～190[°]。例如，圖案3（半透過膜2）和相移膜5可優選使用相同的膜種類（相同組成），也可以爲不同的膜種類。例如可以爲Ti系金屬化合物。Next, as shown in FIG. 3(a), a phase shift film 5 (phase Invert the film). The composition and film thickness are adjusted so that the transmittance of the phase shift film 5 to exposure light (i-ray) is 8 to 15%, and the phase shift amount is 160 to 190 [°]. For example, the pattern 3 (semi-permeable film 2) and the phase shift film 5 may preferably use the same film type (same composition), or may be different film types. For example, it may be a Ti-based metal compound.

接著，如圖3（b）所示，形成抗蝕劑膜6，利用曝光及顯影工藝將抗蝕劑膜6圖案化。在該工序中，除去相當於開口部4的部位的抗蝕劑膜6。即，圖案化的抗蝕劑膜6在被圖案3包圍的區域中露出相移膜5。Next, as shown in FIG. 3(b), a resist film 6 is formed, and the resist film 6 is patterned by exposure and development processes. In this step, the resist film 6 corresponding to the opening 4 is removed. That is, the patterned resist film 6 exposes the phase shift film 5 in the area surrounded by the pattern 3.

接著，如圖3（c）所示，以圖案化的抗蝕劑膜6作爲掩模，利用濕蝕刻法或幹蝕刻法將相移膜5進行蝕刻而圖案化。之後，通過灰化法或浸漬於抗蝕劑剝離液來除去抗蝕劑膜6。如圖3（c）所示，形成由相移膜5形成的第1相移區域7以及由構成圖案3的半透過膜2與相移膜5的層疊形成的第2相移區域8。另外，在開口部4中，露出透過性基板1。Next, as shown in FIG. 3( c ), using the patterned resist film 6 as a mask, the phase shift film 5 is etched and patterned by a wet etching method or a dry etching method. After that, the resist film 6 is removed by an ashing method or immersion in a resist stripping solution. As shown in FIG. 3( c ), the first phase shift area 7 formed by the phase shift film 5 and the second phase shift area 8 formed by the stack of the semipermeable film 2 and the phase shift film 5 constituting the pattern 3 are formed. In addition, in the opening 4, the transmissive substrate 1 is exposed.

圖3（d）是圖3（c）所示工序中的光掩模的俯視圖。以包圍開口部4的方式形成第2相移區域8，進而，以包圍第2相移區域8的方式形成第1相移區域7。因此，第2相移區域8的內周與開口部4的外周相接，第1相移區域7的內周與第2相移區域8的外周相接。第1相移區域7相當於圖1的第1相移部102，第2相移區域8相當於第2相移部103，開口部4相當於透過部101。Fig. 3(d) is a plan view of the photomask in the process shown in Fig. 3(c). The second phase shift area 8 is formed to surround the opening 4, and further, the first phase shift area 7 is formed to surround the second phase shift area 8. Therefore, the inner circumference of the second phase shift area 8 is in contact with the outer circumference of the opening 4, and the inner circumference of the first phase shift area 7 is in contact with the outer circumference of the second phase shift area 8. The first phase shift area 7 corresponds to the first phase shift section 102 in FIG. 1, the second phase shift area 8 corresponds to the second phase shift section 103, and the opening 4 corresponds to the transmission section 101.

第1相移區域7由相移膜5形成，對曝光光的透射率爲8～15%，相移量爲160～190[°]。第2相移區域8由半透過膜2與相移膜5層疊而形成，對曝光光的透射率爲3～7%，相移量爲180～210[°]。只要能够設定成半透過膜2與相移膜5的層疊的相移量爲180～210[°]即可，半透過膜2本身的相移量幷無特別限定。例如半透過膜2本身的相移量可以設定得較小（大致0[°]，例如0～20[°]）。即使在半透過膜2與相移膜5爲相同的膜種類的情況下，也可以將半透過膜2處的相移量設定得較小（減薄膜厚）、將層疊結構的第2相移區域8中的相移量設爲大致180[°]、將透射率調整得較低。The first phase shift area 7 is formed of the phase shift film 5, has a transmittance of 8 to 15% with respect to exposure light, and a phase shift amount of 160 to 190 [°]. The second phase shift region 8 is formed by laminating the semi-permeable film 2 and the phase shift film 5, has a transmittance of 3 to 7% of exposure light, and a phase shift amount of 180 to 210 [°]. As long as it can be set so that the phase shift amount of the stack of the semi-permeable membrane 2 and the phase shift film 5 is 180 to 210 [°], the phase shift amount of the semi-permeable membrane 2 itself is not particularly limited. For example, the phase shift amount of the semi-permeable membrane 2 itself can be set to be small (approximately 0 [°], for example, 0 to 20 [°]). Even when the semi-permeable membrane 2 and the phase shift membrane 5 are of the same film type, the amount of phase shift at the semi-permeable membrane 2 can be set smaller (the film thickness is reduced), and the second phase of the laminated structure can be shifted The phase shift amount in the region 8 is set to approximately 180 [°], and the transmittance is adjusted to be low.

以下，示出代表性的成膜條件例。予以說明，下層膜是指在層疊結構的第2相移區域8中形成於下層側（透過性基板1側）的膜（此時爲半透過膜2），上層膜是指形成於上層側（下層膜上）的膜（此時爲相移膜5）。＜條件1＞：材質　　　：膜種類　　　：膜厚　：透射率：相位差下層膜：Cr系化合物：半色調膜　　：7nm　：60% ：　- 上層膜：Cr系化合物：相移膜：75nm：10% ：185° 層疊：：層疊結構：：5% ：194° ＜條件2＞：材質　　　：膜種類　　　：膜厚　：透射率：相位差下層膜：Cr系化合物：半色調膜　　：15nm ：47% ：　- 上層膜：Cr系化合物：相移膜　　　：67nm ：12% ：174° 層疊　：：層疊結構：　　　：5% ：185° ＜條件3＞：材質　　　：膜種類　　　：膜厚　：透射率：相位差下層膜：Cr系化合物：半色調膜　：17nm ：44% ：　- 上層膜：Cr系化合物：相移膜　　：62nm ：12% ：180° 層疊　：：層疊結構　：　　　：5% ：200°Below, examples of typical film formation conditions are shown. In addition, the lower layer film refers to a film formed on the lower layer side (permeable substrate 1 side) in the second phase shift region 8 of the laminated structure (in this case, the semi-permeable film 2), and the upper layer film refers to a film formed on the upper layer side ( The film on the lower film (phase shift film 5 at this time). ＜Condition 1＞ : Material 　　　: Film type 　　　: Film thickness 　: Transmittance: Retardation Underlayer film: Cr-based compound: Halftone film 　　: 7nm　: 60%: 　- Upper film: Cr-based compound: Phase shift film: 75nm: 10%: 185° Stack: Stacked structure: 5%: 194° ＜Condition 2＞ : Material 　　　: Film type 　　　: Film thickness 　: Transmittance: Retardation Underlayer film: Cr-based compound: halftone film 　　: 15nm ：47%: 　- Upper film: Cr-based compound: Phase shift film 　　　: 67nm ：12% ：174° Stacking: Stacking structure: 5%: 185° <Condition 3> ：Material 　　　: Film type 　　　: Film thickness 　: Transmittance: Phase difference Underlayer film: Cr-based compound: Halftone film 　: 17nm: 44%: 　- Upper film: Cr-based compound: Phase shift film 　　: 62nm: 12%: 180° Stacking: Stacking structure: 5%: 200°

在上述例中，透射率低的第2相移區域8由半透過膜2與相移膜5的層疊形成，通過相移膜5來確定相移量的值的大部分。相移膜5可以優選使用相移量的波長依賴性低的、例如相移的變動爲20[°]以內的非波長依賴型半色調膜（所謂“FLAT膜”）。但是，由於只要滿足上述條件即可，因此幷不限定於非波長依賴型半色調膜。另外，關於半透過膜2，例如也可以採用相移量小的條件（膜厚等），無需特別採用非波長依賴型半色調膜，可以採用通常的半透過膜（波長依賴型半色調膜）或非波長依賴型半色調膜中的任一種膜。In the above example, the second phase shift region 8 with low transmittance is formed by the stack of the semi-permeable film 2 and the phase shift film 5, and the phase shift film 5 determines most of the value of the phase shift amount. The phase shift film 5 can preferably use a wavelength-independent halftone film (so-called "FLAT film") in which the phase shift amount has a low wavelength dependency, for example, a phase shift variation within 20[°]. However, as long as the above conditions are satisfied, it is not limited to a wavelength-independent halftone film. Regarding the semi-permeable film 2, for example, conditions with a small amount of phase shift (film thickness, etc.) can also be adopted, and there is no need to particularly use a wavelength-independent halftone film, and a normal semi-permeable film (wavelength-dependent halftone film) can be used. Or any of the wavelength-independent halftone films.

予以說明，半透過膜2及相移膜5的圖案化方法幷不限定於上述圖2、圖3所示的方法。例如在圖2（b）的工序中，將相當於第1相移部102的區域的半透過膜2蝕刻（即保留相當於透過部101和第2相移部103的區域的半透過膜2），之後形成相移膜5，在圖3（b）的工序中，可以將相當於開口部4（透過部101）的區域的半透過膜2及相移膜5的層疊蝕刻。Incidentally, the patterning method of the semipermeable film 2 and the phase shift film 5 is not limited to the method shown in FIGS. 2 and 3 described above. For example, in the process of FIG. 2(b), the semi-permeable film 2 in the area corresponding to the first phase shift part 102 is etched (that is, the semi-permeable film 2 in the area corresponding to the transparent part 101 and the second phase shift part 103 is left ), and then the phase shift film 5 is formed. In the step of FIG. 3(b), the semi-permeable film 2 and the phase shift film 5 in the region corresponding to the opening 4 (transmission section 101) can be laminated and etched.

予以說明，半透過膜2及相移膜5的材質幷不限定於Cr金屬化合物。也可以使用已知的其他金屬系化合物。It should be noted that the materials of the semi-permeable film 2 and the phase shift film 5 are not limited to Cr metal compounds. Other known metal-based compounds can also be used.

（實施方式2）在上述實施方式1中，對在透過性基板1上形成半透過膜2幷在圖案化後形成相移膜5來製造光掩模100的方法進行了說明。但是，也可以在透過性基板1上形成相移膜5後再形成半透過膜2。即，在第2相移部103中，半透過膜2與相移膜5的上下關係可以構成爲與實施方式1相反。以下，對實施方式2的光掩模100的製造工序進行說明。(Embodiment 2) In the first embodiment described above, the method of manufacturing the photomask 100 by forming the semi-permeable film 2 on the transmissive substrate 1 and then forming the phase shift film 5 after patterning has been described. However, it is also possible to form the semi-permeable film 2 after forming the phase shift film 5 on the permeable substrate 1. That is, in the second phase shift portion 103, the vertical relationship between the semi-permeable membrane 2 and the phase shift membrane 5 may be configured to be opposite to that of the first embodiment. Hereinafter, the manufacturing process of the photomask 100 of Embodiment 2 is demonstrated.

如圖4（a）所示，利用濺射法、蒸鍍法等在透過性基板1上形成相移膜5（相位反轉膜）。相移膜5的透射率及相移量如上述所示。As shown in FIG. 4( a ), a phase shift film 5 (phase inversion film) is formed on the transmissive substrate 1 by a sputtering method, a vapor deposition method, or the like. The transmittance and phase shift amount of the phase shift film 5 are as described above.

接著，如圖4（b）所示，利用濺射法、蒸鍍法等形成半透過膜2。半透過膜2的透射率如上述所示。之後，形成抗蝕劑膜9（第1抗蝕劑膜），利用曝光及顯影工藝將抗蝕劑膜9圖案化。在該工序中，除去相當於開口部4的部位的抗蝕劑膜9。Next, as shown in FIG. 4( b ), the semi-permeable film 2 is formed by a sputtering method, an evaporation method, or the like. The transmittance of the semi-permeable film 2 is as described above. After that, a resist film 9 (first resist film) is formed, and the resist film 9 is patterned by exposure and development processes. In this step, the resist film 9 corresponding to the opening 4 is removed.

接著，如圖4（c）所示，以抗蝕劑膜9作爲掩模，利用例如濕蝕刻法或幹蝕刻法將半透過膜2及相移膜5進行蝕刻。在半透過膜2及相移膜5形成開口部4，露出透過性基板1。之後，通過灰化法或浸漬於抗蝕劑剝離液來除去抗蝕劑膜9。予以說明，爲了後續的光刻，也可以將半透過膜2及相移膜5的層疊進行圖案化而適當形成對準標記。Next, as shown in FIG. 4( c ), using the resist film 9 as a mask, the semi-permeable film 2 and the phase shift film 5 are etched by, for example, a wet etching method or a dry etching method. An opening 4 is formed in the semipermeable film 2 and the phase shift film 5 to expose the transmissive substrate 1. After that, the resist film 9 is removed by an ashing method or immersion in a resist stripping solution. In addition, for the subsequent photolithography, the stack of the semi-permeable film 2 and the phase shift film 5 may be patterned to form an alignment mark as appropriate.

接著，如圖4（d）所示，形成抗蝕劑膜10（第2抗蝕劑膜），利用曝光及顯影工藝將抗蝕劑膜10圖案化。抗蝕劑膜10的圖案以包圍開口部4、且與半透過膜2及相移膜5的層疊膜重疊的方式來構成。重疊寬度設定爲R。保留由開口部4和包圍該開口部4的第2相移區域8構成的圖案區域的抗蝕劑膜10。予以說明，重疊寬度可以考慮在後續的半透過膜2的蝕刻工序中的側蝕刻量而設定成R加上側蝕刻量所得的值。Next, as shown in FIG. 4(d), a resist film 10 (second resist film) is formed, and the resist film 10 is patterned by exposure and development processes. The pattern of the resist film 10 is constituted so as to surround the opening 4 and overlap with the laminated film of the semi-permeable film 2 and the phase shift film 5. The overlap width is set to R. The resist film 10 is left in the pattern area constituted by the opening 4 and the second phase shift area 8 surrounding the opening 4. Incidentally, the overlap width can be set to a value obtained by adding R and the amount of side etching in consideration of the amount of side etching in the subsequent etching step of the semi-permeable film 2.

接著，如圖5（a）所示，以抗蝕劑膜10作爲掩模，利用例如濕蝕刻法或幹蝕刻法將相移膜5上的半透過膜2進行蝕刻。之後，通過灰化法或浸漬於抗蝕劑剝離液來除去抗蝕劑膜10。予以說明，爲了保留相移膜5而對相移膜5上的半透過膜2進行蝕刻，相移膜5和半透過膜2可優選由不同的材料構成。例如可以使用相移膜5和半透過膜2中的一者由Cr系金屬化合物構成、另一者由Ti系金屬化合物構成的組合。其結果可以選擇性地蝕刻相移膜5上的半透過膜2。另外，也可以通過使相移膜5和半透過膜2由相同材料構成，幷且將蝕刻時間設定成與半透過膜2的蝕刻時間相同，從而除去相移膜5上的半透過膜2。Next, as shown in FIG. 5( a ), using the resist film 10 as a mask, the semi-permeable film 2 on the phase shift film 5 is etched by, for example, a wet etching method or a dry etching method. After that, the resist film 10 is removed by an ashing method or immersion in a resist stripping solution. In addition, the semi-permeable film 2 on the phase shift film 5 is etched in order to retain the phase shift film 5, and the phase shift film 5 and the semi-permeable film 2 may preferably be composed of different materials. For example, a combination in which one of the phase shift film 5 and the semipermeable film 2 is made of a Cr-based metal compound and the other is made of a Ti-based metal compound can be used. As a result, the semi-permeable film 2 on the phase shift film 5 can be selectively etched. In addition, the phase shift film 5 and the semi-permeable film 2 may be made of the same material, and the etching time is set to be the same as the etching time of the semi-permeable film 2 to remove the semi-permeable film 2 on the phase shift film 5.

圖5（b）是圖5（a）中的光掩模的俯視圖。以包圍開口部4的方式形成寬度R的第2相移區域8，進而，以包圍第2相移區域8的方式形成第1相移區域7。與圖3（d）所示的第2相移區域8在半透過膜2上形成相移膜5不同，圖5（b）所示的第2相移區域8在相移膜5上形成半透過膜2。在本實施方式2中，能够得到DOF和曝光量的改善效果是不言而喻的。Fig. 5(b) is a plan view of the photomask in Fig. 5(a). The second phase shift region 8 with a width R is formed to surround the opening 4, and the first phase shift region 7 is further formed to surround the second phase shift region 8. Unlike the second phase shift area 8 shown in FIG. 3(d) where the phase shift film 5 is formed on the semi-permeable film 2, the second phase shift area 8 shown in FIG. 5(b) is formed on the phase shift film 5.透膜2。 Through the membrane 2. In the second embodiment, it is self-evident that the effect of improving the DOF and the exposure amount can be obtained.

與實施方式1的光掩模的製造方法相比，實施方式2的光掩模的製造方法是在平坦的相移膜5上形成半透過膜2，因此容易進行半透過膜2的成膜。另一方面，與實施方式1的光掩模的製造方法相比，實施方式2的光掩模的製造方法需要將形成於第2相移區域8的上層的膜在形成於下層的膜上進行蝕刻，因此需要準確地進行蝕刻的控制。Compared with the manufacturing method of the photomask of the first embodiment, the manufacturing method of the photomask of the second embodiment forms the semi-permeable film 2 on the flat phase shift film 5, so that the semi-permeable film 2 is easily formed. On the other hand, compared with the photomask manufacturing method of Embodiment 1, the photomask manufacturing method of Embodiment 2 requires that the film formed on the upper layer of the second phase shift region 8 is formed on the film formed on the lower layer. Etching, therefore, it is necessary to accurately control the etching.

予以說明，在上述實施方式2中，在相移膜5上形成了半透過膜2，但是在相移膜5和半透過膜2由相同材質構成的情況下，也可以不採用層疊結構而形成與相移膜5的膜厚和半透過膜2的膜厚之和相等的相移膜51。在圖4（b）的工序中，將相移膜5與半透過膜2的層疊置換爲單層的相移膜51，然後使用抗蝕劑膜9進行蝕刻，可以利用圖4（c）～圖5（a）的工序來形成第1相移區域7及第2相移區域8。在該情況下，在圖5（a）的工序中調整相移膜51的蝕刻量（蝕刻時間），第2相移區域8可以構成爲比第1相移區域7厚出所期望的厚度。其結果能够將第2相移區域8的透射率設定得比第1相移區域7低。 [產業上的可利用性]In addition, in the second embodiment described above, the semi-permeable film 2 is formed on the phase shift film 5. However, when the phase shift film 5 and the semi-permeable film 2 are made of the same material, they may be formed without using a laminated structure. The phase shift film 51 is equal to the sum of the film thickness of the phase shift film 5 and the film thickness of the semi-permeable film 2. In the step of FIG. 4(b), the stack of the phase shift film 5 and the semi-permeable film 2 is replaced with a single-layer phase shift film 51, and then the resist film 9 is used for etching, and FIG. 4(c)~ The process of FIG. 5( a) forms the first phase shift area 7 and the second phase shift area 8. In this case, by adjusting the etching amount (etching time) of the phase shift film 51 in the step of FIG. 5( a ), the second phase shift region 8 may be configured to be thicker than the first phase shift region 7 by a desired thickness. As a result, the transmittance of the second phase shift region 8 can be set lower than that of the first phase shift region 7. [Industrial availability]

根據本發明，可以提供能够穩定地解像微細的孔圖案的光掩模，可優選利用於例如平板顯示器等顯示裝置用電子設備的製造工序中，産業上的可利用性大。可特別優選利用於像顯示裝置用電子設備的製造那樣對DOF的要求值嚴格的光刻工序中。According to the present invention, a photomask capable of stably resolving fine hole patterns can be provided, and it can be preferably used in the manufacturing process of electronic devices for display devices such as flat panel displays, and has great industrial applicability. It can be particularly preferably used in a photolithography process that requires strict DOF, such as the manufacture of electronic equipment for display devices.

1:透過性基板 2:半透過膜 3:圖案 4:開口部 5:相移膜 6:抗蝕劑膜 7:第1相移區域 8:第2相移區域 9:抗蝕劑膜 10:抗蝕劑膜 51:相移膜 100:光掩模 101:透過部 102:第1相移部 103:第2相移部1: Transparent substrate 2: Semi-permeable membrane 3: pattern 4: opening 5: Phase shift film 6: Resist film 7: The first phase shift area 8: 2nd phase shift area 9: resist film 10: Resist film 51: Phase shift film 100: photomask 101: Through Department 102: The first phase shift part 103: 2nd phase shift part

圖1（a）是實施方式1的光掩模的俯視圖，圖1（b）、圖1（c）用於說明其光刻特性（DOF及所需曝光量）的改善效果的圖表。圖2（a）、圖2（b）是表示實施方式1的光掩模的主要工序的剖視圖，圖2（c）是其俯視圖。圖3（a）～圖3（c）是表示實施方式1的光掩模的主要工序的剖視圖，圖3（d）是其俯視圖。圖4是表示實施方式2的光掩模的主要工序的剖視圖。圖5（a）是表示實施方式2的光掩模的主要工序的剖視圖，圖5（a）是其俯視圖。FIG. 1(a) is a plan view of the photomask of Embodiment 1, and FIG. 1(b) and FIG. 1(c) are graphs for explaining the effect of improving the photolithography characteristics (DOF and required exposure amount). 2(a) and 2(b) are cross-sectional views showing main steps of the photomask of Embodiment 1, and FIG. 2(c) is a plan view thereof. 3(a) to 3(c) are cross-sectional views showing main steps of the photomask of Embodiment 1, and FIG. 3(d) is a plan view thereof. 4 is a cross-sectional view showing main steps of the photomask of the second embodiment. FIG. 5(a) is a cross-sectional view showing main steps of the photomask of Embodiment 2, and FIG. 5(a) is a plan view thereof.

100:光掩模100: photomask

101:透過部101: Through Department

102:第1相移部102: The first phase shift part

103:第2相移部103: 2nd phase shift part

Claims

一種光掩模，其特徵在於，具備透過部、第1相移部和第2相移部，所述第1相移部及所述第2相移部包圍所述透過部，所述第2相移部介於所述第1相移部與所述透過部之間，所述第2相移部及所述第1相移部將曝光光的相位反轉，所述第2相移部的透射率比所述第1相移部的透射率低。A photomask characterized by having a transmission part, a first phase shift part, and a second phase shift part, The first phase shift part and the second phase shift part surround the transmission part, The second phase shift part is interposed between the first phase shift part and the transmission part, The second phase shift part and the first phase shift part invert the phase of the exposure light, The transmittance of the second phase shift part is lower than the transmittance of the first phase shift part.

如請求項1所述的光掩模，其中，所述第1相移部的透射率爲8～15%，所述第2相移部的透射率爲3～7%。The photomask according to claim 1, wherein the transmittance of the first phase shift portion is 8 to 15%, and the transmittance of the second phase shift portion is 3 to 7%.

如請求項1或2所述的光掩模，其中，所述第1相移部及所述第2相移部的相移量爲160[°]以上且210[°]以下的範圍。The photomask according to claim 1 or 2, wherein the phase shift amount of the first phase shift portion and the second phase shift portion is in a range of 160 [°] or more and 210 [°] or less.

如請求項1~3中任一項所述的光掩模，其中，所述第1相移部的相移量爲160[°]以上且190[°]以下的範圍，所述第2相移部的相移量爲180[°]以上且210[°]以下的範圍。The photomask according to any one of claims 1 to 3, wherein the phase shift amount of the first phase shift portion is in a range of 160 [°] or more and 190 [°] or less, and the second phase The phase shift amount of the shift part is in the range of 180 [°] or more and 210 [°] or less.

如請求項1~4中任一項所述的光掩模，其中，所述第2相移部是構成所述第1相移部的相移膜與半透過膜的層疊。The photomask according to any one of claims 1 to 4, wherein the second phase shift part is a stack of a phase shift film and a semipermeable film constituting the first phase shift part.