WO2010074481A2

WO2010074481A2 - Half tone mask and fabricating method

Info

Publication number: WO2010074481A2
Application number: PCT/KR2009/007666
Authority: WO
Inventors: Seung Ho Back; Joo Hyun Hwang; Jin Ho Hong; Seung Han Kang
Original assignee: LG Innotek Co Ltd
Current assignee: LG Innotek Co Ltd
Priority date: 2008-12-22
Filing date: 2009-12-22
Publication date: 2010-07-01
Anticipated expiration: 2011-06-22
Also published as: CN102265381A; TW201033727A; KR101079161B1; TWI575304B; WO2010074481A3; KR20100072403A; JP2012513620A

Abstract

A half tone mask and a fabricating method is disclosed where the half tone mask capable of adjusting optical transmittance is provided by stacking translucent materials, wherein the optical transmittance can be implemented that is built up through data base based on, not the theoretical behavior characteristic, but on the actual process, whereby the half tone mask having a transmittance in a wide range of regions, rather than a transmittance in a particular region, can be provided.

Description

HALF TONE MASK AND FABRICATING METHOD

The present invention relates to a half tone mask formed with light interruption region, a translucent region and a transmissive region on a transparent substrate and a fabricating method.

Multiple configurations employed for fabricating liquid crystal displays need multiple mask methods. As a result, fabricating methods become complicated to create a problem of increasing a fabricating cost of a liquid crystal display device. As one of ways for solving the above problems, a current trend is going toward reducing the processing number of masks.

A common photo-mask used in patterning by way of photolithography process includes, as illustrated in FIG.1, a transparent substrate 11, a light transmission unit 13 formed on the transparent substrate 11capable of completely transmitting light and a light interruption unit 15 capable of completely interrupting the light. The conventional mask can only be used in one cycle of photolithography process formed by an exposure-development -etching because the conventional mask can only implement one layer of pattern.

To be more specific, TFT (Thin Film Transistor) and CF (Color Filter) are deposited/coated with lots of layers, and each deposited/coated layer is patterned by photolithography process. Meanwhile, there may be a great economic effect if only one cycle of photolithography process is reduced. However, the conventional mask has a structure of implementing only one layer of pattern, such that an unnecessary non-economical efficiency of manufacturing lots of photo-masks implementing separate patterns exists.

In order to obviate the above-mentioned disadvantages, a slit mask, a gray tone mask and a half tone mask have been developed.

The slit mask uses a scattering property of an entire optical energy in which the light is scattered to adjacent portions when passing a slim slit instead of a slit guaranteeing linearity of wavelength.

However, in case of the slit mask, distribution of light scattered in a fine slit is not uniform to make an exposure energy differentiated for each position, such that it is difficult to obtain a uniform thickness of residual films due to formation of concaveness and convexness in residual film thickness for each position.

The gray tone mask has a structure having a transmissive part through which light completely passes, a light interruption part completely interrupting light and a slit pattern passing light by reducing amount of irradiated light.

However, the disadvantage of the gray tone mask is that, due to the fact that the amount of transmissive light is adjusted by using the diffraction phenomenon of light that passes the fine pattern, there is a limit in implementing the slit pattern to thereby restrict the transmissive amount of light capable of being adjusted, such that in case of the gray mask having a size larger than a predetermined dimension cannot implement a uniform patterning.

The half tone mask is a mask having a transparent portion formed on a transparent substrate that completely passes light, a light interruption portion completely interrupting light and a translucent portion capable of adjusting the transmittance to allow light to partially pass.

The half tone mask is advantageous in that light having passed the translucent portion is allowed to uniformly pass for each position to form a uniform residual film thickness for each position. However, the half tone mask suffers from a disadvantage in that it requires an additional process for mask manufacturing to increase the fabricating cost and the number of fabricating processes. The problem of reducing a plurality of mask processes still exists in the half tone mask at the same time.

The present invention is disclosed to solve the aforementioned problems and it is an object of the present invention to provide a half tone mask capable of adjusting optical transmittance by stacking translucent materials, wherein the optical transmittance can be implemented that is built up through data base based on, not the theoretical behavior characteristic, but on the actual process, whereby a half tone mask having a transmittance in a wide range of regions, rather than a transmittance in a particular region, can be provided.

It is another object to provide a fabricating method of a half tone mask capable of increasing precision of half tone mask being fabricated by implementing an optical transmittance necessary for stacking a translucent region with translucent materials to reduce the number of manufacturing processes, and to implement a translucent region by restricting a fluctuation range of optical transmittance between adjacent translucent regions on which the to-be-formed half tone mask is formed in the range of 4 ~ 75%, in manufacturing a multi-tone mask formed with a half tone mask and a plurality of translucent regions.

In some exemplary embodiment, a half tone mask is formed with a plural number (N) of translucent portions each having a different optical transmittance by being stacked with at least one or more translucent materials.

In some exemplary embodiment, in consideration of adjustment width of maximum transmittance capable of fine adjustment in the actual fabricating process, the plural number (N) of translucent portions is such that difference of optical transmittance in adjacent translucent portions is within the range of 4% ~75%.

In some exemplary embodiments, the adjustment of transmittance forms the translucent portions, wherein the transmittance is adjusted by stacked structure of translucent materials each having the same material, or adjusted by stacked structure of translucent materials each having a different material, or by stacked structure of translucent materials each combined with same or different materials.

In some exemplary embodiments, the material forming the translucent materials forming the translucent portions is a material having as a main element one of Cr, Si, Mo, Ta, Ti, Al, Zr, Sn, Zn, In, Mg, Hf, V, Nd, Ge, MgO-Al₂O₃ or Si₃N₄, or is a combined material mixed with at least the two or more elements, or is a material added with at least one of Cox, Ox, Nx, Cx, Fx or Bx to the single main element material or the combined materials.

It should be apparent that the present invention can perform a fabricating method for fabricating the abovementioned half tone mask.

To be more specific, in a fabricating method of a half tone mask formed with at least one or more translucent portions, wherein each translucent portion is stacked with a plurality of translucent materials to adjust an optical transmittance.

In some exemplary embodiments, the step of adjusting the optical transmittance by stacking the translucent materials may comprise sequential removing steps of removing an unnecessary pattern following sequential stacking of the translucent materials.

In some exemplary embodiments, the step of adjusting the optical transmittance by stacking the translucent materials may comprise sequentially stacking the translucent materials to remove the unnecessary pattern while forming translucent portions at particular numbers of locations on the halftone mask (sequential removing step).

That is, the translucent materials necessary for adjusting the transmittance are sequentially stacked and then sequentially removed, whereby the optical transmittance is adjusted by leaving necessary translucent materials to thereby form a translucent portion having a multiple optical transmittance through a very simple process.

In some exemplary embodiments, the step of adjusting the optical transmittance by stacking the translucent materials may comprise: sequentially stacking the translucent materials to remove the unnecessary pattern while forming translucent portions at particular numbers of locations on the halftone mask; and independently forming particular translucent layers, whereby translucent portions each having a different optical transmittance can be formed.

In addition, it should be apparent that the step of adjusting the optical transmittance by stacking the translucent materials may comprise a step of independently performing the sequential removal step or the independent forming step is independently performed at at least one or more locations of the halftone mask to form the translucent portion.

As explained above in the half tone mask, the translucent portions are formed in plural numbers, and a difference of optical transmittance between adjacent translucent portions is preferred to be in the range of 4% ~75%.

In some exemplary embodiments, the step of removing particularly-stacked translucent materials in the entire process may use a method of photolithography.

The present invention is advantageous in that a half tone mask capable of adjusting optical transmittance can be provided by stacking translucent materials, wherein the optical transmittance can be implemented that is built up through data base based on, not the theoretical behavior characteristic, but on the actual process, whereby a half tone mask having a transmittance in a wide range of regions, rather than a transmittance in a particular region, can be provided.

There is another advantage in that, in manufacturing a multi-tone mask formed with a half tone mask and a plurality of translucent regions, a necessary optical transmittance can be implemented by stacking translucent materials in the translucent portions to thereby reduce the fabricating process.

There is still another advantage in that a fluctuation range of optical transmittance between adjacent translucent regions is restricted to a range of 4 ~ 75% to increase precision of the manufactured half tone mask.

There is still further advantage in that adjacent translucent portions can be remarkably differentiated by precise restriction on the transmittance to ease the control of transcribed pattern (pattern of a product formed by using the mask) to allow forming multiple layers using one mask and to facilitate an easy transcribed pattern formation.

FIG. 1 is a conceptual drawing illustrating the conventional photo-mask.

FIG. 2 is a schematic view explaining behavior characteristic of transmittance in a stacked structure of a half tone mask.

FIGS. 3 and 4 are schematic views illustrating an exemplary embodiment of a translucent portion according to the present invention.

FIGS. 5a and 5b are conceptual drawings explaining a transmittance adjustment in a translucent portion and a stacking process thereof according to the present invention.

FIGS. 6a and 6b are schematic views illustrating a structure of a translucent portion according to another exemplary embodiment of the present invention and fabricating method thereof.

FIGS. 7a, 7b and 7c are schematic views illustrating a structure of a translucent portion according to still another exemplary embodiment of the present invention and fabricating method thereof.

Structure and fabricating method according to the present invention will be described in detail with reference to the accompanying drawings.

The gist of the present invention is to provide a half tone mask formed with a plurality of translucent portions on a half tone mask by adjusting an optical transmittance by stacking at least one or more translucent materials.

FIG.2 is a schematic view explaining behavior characteristic of transmittance in a stacked structure of a half tone mask.

Now, an example of a half tone mask comprising an light interruption portion (C) formed with an optical interruption layer (110) on a substrate (100), translucent portions (A, B) adjusting an optical transmittance by stacking translucent layers (120, 130) and a light completely transmissive portion (D), where D portion is the complete transmissive part.

That is, the light interruption portion (C) has a zero (0 percent) optical transmittance, the light completely transmissive portion (D) has a 100% optical transmittance, and the translucent layer (120) has a 70% optical transmittance, and the translucent layer (130) has a 35% optical transmittance.

Theoretically, a final optical transmittance of light that passes the above translucent portions must be approximately 25%, because of 70% optical transmittance at the translucent layer (120) and 35% optical transmittance at the translucent layer (130). However, the theoretical transmittance is hardly applied in actual fabricating processes, and a behavior characteristic of actual transmittance has a difference of 25% transmittance in the A portion, such that it is very difficult to calculate an accurate transmittance. That is, it is very difficult to adjust the transmittance by stacking translucent materials in the actual processes.

The present invention implements a fine error of the optical transmittance in the range of 4 ~ 75% in the stacked structure of translucent material to form a plurality of translucent portions in one single half tone mask. There may be a fatal problem of failing to discriminate the adjacent translucent portions if the fluctuation width of the transmittance between adjacent translucent portions is within a range of less than 4%. That is, there is no discrimination of each translucent portion where the fluctuation width of the transmittance between adjacent translucent portions is within a range of less than 4%, whereby a pattern transcribed in each translucent portion becomes obscure to generate a defect between patterns after the transcription.

Therefore, in formation of translucent portions according to the present disclosure, the transmittance is adjusted by a structure stacked with at least one or more translucent materials capable of adjusting transmittance.

The material forming the translucent materials may be a material having as a main element one of Cr, Si, Mo, Ta, Ti, Al, Zr, Sn, Zn, In, Mg, Hf, V, Nd, Ge, MgO-Al₂O₃ or Si₃N₄, or may be a combined material mixed with at least the two or more elements, or may be a material added with at least one of Cox, Ox, Nx, Cx, Fx or Bx to the single main element material or the combined materials. The translucent material forming each stacked structure is a stacked structure of the same selected material, or a stacked structure of mutually different materials, or a complex stacked structure of these two structures, where the suffix x, y and z is a natural number.

The most salient feature of the present disclosure is that the translucent portions are formed in multiple structures each of which has a mutually different optical transmittance. Another feature is that the adjustment of the optical transmittance is controlled by a stacked structure comprising one or more translucent materials.

Of course, the optical transmittance of translucent material forming the individually stacked translucent portions can be adjusted by varying the composition or thickness of the translucent material. That is, the property of composition forming the translucent material can change the optical transmittance, and difference of thickness in the same composition can adjust the optical transmittance.

As noted above, materials comprising the translucent materials may be a material having as a main element one of Cr, Si, Mo, Ta, Ti, Al, Zr, Sn, Zn, In, Mg, Hf, V, Nd, Ge, MgO-Al₂O₃ or Si₃N₄, which has been already expounded.

Alternatively, the materials may be is a combined material mixed with at least the two or more elements, or is a material added with at least one of Cox, Ox, Nx, Cx, Fx or Bx to the single main element material or the combined materials.

It should be noted that the composition of the stacked translucent portions may be variably applied as long as part of light irradiated can pass therethrough. For example, the stacked translucent portions may be formed by any one or combination of Cr_xO_y, Cr_xCO_y, Cr_xO_yN_z, Si_xO_y, Si_xO_yN_z, Si_xCO_y, Si_xCO_yN_z, Mo_xSi_y, Mo_xO_y, Mo_xO_yN_z, Mo_xCO_y, Mo_xO_yN_z, Mo_xSi_yO_z, Mo_xSi_yO_zN Mo_xSi_yCO_zN, Mo_xSi_yCO_z, Ta_xO_y, Ta_xO_yN_z, Ta_xCO_y, Ta_xO_yN_z, Al_xO_y, Al_xCO_y, Al_xO_yN_z, Al_xCO_yN_z, Ti_xO_y, Ti_xO_yN_z, Ti_xCO_y, where the suffix x, y and z is a natural number and defines the number of each chemical element.

FIG. 3 is a schematic view illustrating an exemplary embodiment of a translucent portion according to the present invention. In other words, the translucent portion is formed by 3 types of translucent materials stacked on a substrate. It should be apparent that the structure may be formed in a singular form or in a plural form on a single half tone mask according to the need. It should be also obvious that the translucent materials may be laid on a light interruption film to form a light interruption portion.

If a transmittance of a first translucent material (H1) is x %, a transmittance of a second translucent material (H2) is y % and a transmittance of a third translucent material (H3) is z %, portions formed by the 3 different transmittances may be an A portion, a B portion and a C portion.

Particularly, z% of light will ultimately pass the C portion, (z X y) % of light will pass the B portion and {(z X y) X x}% of light will pass the C portion. It is preferable that a variation width of optical transmittance in respective A, B and C portion be adjusted to a range of 4% ~75% according to the transmissive characteristics.

Based on this adjustment, a structure of using only a particular transmittance can be avoided to implement a translucent portion through precise adjustment of transmittance in a stacked style of half tone materials in forming translucent portions on the half tone mask.

FIG. 4 is a schematic view illustrating another exemplary embodiment of a translucent portion stacked by a first translucent material (H1, x % of transmittance), a second translucent material (H2, y % of transmittance) and a third translucent material (H3, z % of transmittance) in FIG.3.

That is, the gist of the present invention is that a plurality of translucent materials is stacked on a single half tone mask to adjust each transmittance, whereby an adjustment width of transmittance between adjacent translucent materials is in the range of 4% ~75%, such that the manufacturing cost efficiency can be enhanced by forming translucent portions each having a different transmittance on a single half tone mask to dispense with manufacturing separate masks.

Now, the transmittance adjustment control method will be described with reference to FIG.5a.

A stacked structure of translucent materials for forming the translucent portions is implemented based on data-based experimental data.

First of all, transmittance of each material is formed from data base of each translucent material (DB₁~DBn, where n is a natural number) and a transmittance to be implemented in a particular translucent portion on a half tone mask is selected.

Thereafter, a transmittance to be sputtered in the first translucent material is selected, and a transmittance to be sputtered in the second translucent material is selected. Further, the transmittances of the first and second translucent materials are realized and a transmittance of a combined layer of two films is also embodied.

The database of transmittances is stored in a transmittance database (210), and particularly, calculation of each transmittance is made by a controller (220) to enable formation of a layer (230) on a substrate, whereby two or more transmittances can be implemented within a single mask, and quantitative data stored in the database can be reproduced with oneness or sameness.

The following Table exemplifies a calculation result of transmittance in the stacked translucent portions in the quantitative format according to exemplary embodiment of the present invention.

{Table 1}

where, 'reference T (%)' is a transmittance of 'reference layer (R)' of FIG.5b, and X (%) of FIG.5b defines a transmittance of translucent layers stacked on the reference layer (R).

Now, a calculation example of transmittance based on the stacked layer of the translucent portion relative to Table 1 will be explained with reference to FIG.5b.

The transmittance (Y) of the finally stacked translucent portion may be calculated quantitatively by the above Table 1. Of course, the above calculated data may be changed if transmittance of the translucent portion (reference layer: R) is changed.

FIGS. 6 shows exemplary embodiments of various translucent portions according to the present invention. The fabricating method of translucent portions of a half tone mask will be described with reference to the illustrated structures.

The fabricating method of a half tone mask, which is a known art in which an light interruption portion, a transmissive portion and a translucent portion are stacked on a substrate, and patterned, is omitted for convenience sake.

However, a fabricating method capable of forming a plurality of translucent portions each having a different optical transmittance by stacking a plurality of translucent materials and adjusting the transmittances in a forming process of a single half tone mask according to the present invention will described.

FIG.6a is a conceptual schematic view of a plurality of translucent portions performed in the similar methods to those in FIGS. 3 and 4.

The first translucent material (H1), the second translucent material (H2) and the third translucent material (H3) may be sequentially stacked, and unnecessary sections at each portion are removed according to the sequential removal process. That is, (b-1) a photo-resist (PR) is formed on the third translucent material (H3), part of the third translucent material (H3) is removed through exposure and development, (b-2) photo-resist (PR) is formed to remove part of the second translucent material (H2), (b-3) and finally a translucent portion formed with A, B, C portions is formed, where the variation width of optical transmittance between adjacent portions is preferred to be in the range of 4% ~75%, and where D portion is a complete transmissive portion.

The structures in the translucent portions in FIGS.7a and 7b may be also such that each translucent material is sequentially stacked, and a sequential removal process is performed using the photo-resist, where the complete transmissive portion (P) is formed by completely removing each of the stacked translucent materials in the patterning of the photo-resist in the sequential removal process.

The A and B portions in FIG.7b may be formed by a simplified process through the aforementioned sequential removal method, but the C portion may be implemented through an independently forming process that forms H3 translucent material independently.

In case of variously structured translucent portion in FIG.7c, the A portion may be formed by the sequential removal process while the B and C portions may be formed by the independently forming process.

The present invention is applicable to industries in that a half tone mask capable of adjusting optical transmittance can be provided by stacking translucent materials, wherein the optical transmittance can be implemented that is built up through data base based on, not the theoretical behavior characteristic, but on the actual process, whereby a half tone mask having a transmittance in a wide range of regions, rather than a transmittance in a particular region, can be provided.

There is another application in that, in manufacturing a multi-tone mask formed with a half tone mask and a plurality of translucent regions, a necessary optical transmittance can be implemented by stacking translucent materials in the translucent portions to thereby reduce the fabricating process.

There is still another application to the industries in that a fluctuation range of optical transmittance between adjacent translucent regions is restricted to a range of 4 ~ 75% to increase precision of the manufactured half tone mask.

There is still further application to the industries in that adjacent translucent portions can be remarkably differentiated by precise restriction on the transmittance to ease the control of transcribed pattern (pattern of a product formed by using the mask) to allow forming multiple layers using one mask and to facilitate an easy transcribed pattern formation.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

A half tone mask formed with a plurality of translucent portions each having a different optical transmittance by being stacked with at least one or more translucent materials.
A half tone mask formed with a plurality of translucent portions, wherein the plurality of translucent portions has an optical transmittance different from that of an adjacent translucent portion within the range of 4% ~75%.
The half tone mask of claim 1 or 2, wherein the plurality of translucent portions in stacked structure of translucent materials each having the same material adjusts transmittance.
The half tone mask of claim 1 or 2, wherein the plurality of translucent portions in stacked structure of translucent materials each having a different material adjusts transmittance.
The half tone mask of claim 1 or 2, wherein the plurality of translucent portions in stacked structure of translucent materials each combined with same or different materials adjusts transmittance.
The half tone mask of claim 1 or 2, wherein the material forming the translucent materials is a material having as a main element one of Cr, Si, Mo, Ta, Ti, Al, Zr, Sn, Zn, In, Mg, Hf, V, Nd, Ge, MgO-Al₂O₃ or Si₃N₄, or is a combined material mixed with at least the two or more elements, or is a material added with at least one of Cox, Ox, Nx, Cx, Fx or Bx to the single main element material or the combined materials, where the suffix x, y and z is a natural number and means the number of each chemical element.
A fabricating method of a half tone mask, the method formed with at least one or more translucent portions, wherein each translucent portion is stacked with a plurality of translucent materials to adjust an optical transmittance.
The method of claim 7, wherein the step of adjusting the optical transmittance by stacking the translucent materials includes a sequential removal step of removing an unnecessary pattern following sequential stacking of the translucent materials.
The method of claim 7, wherein the step of adjusting the optical transmittance by stacking the translucent materials comprises: sequentially stacking the translucent materials to remove the unnecessary pattern while forming translucent portions at particular numbers of locations on the halftone mask; and independently forming particular translucent layers.
The method of claim 7 or 8, wherein the step of adjusting the optical transmittance by stacking the translucent materials includes a step of independently performing the sequential removal step or the independent forming step is independently performed at least one or more locations of the halftone mask to form the translucent portion.
The method of any one claim from 7 to 9, wherein the translucent portions are formed in plural numbers, and wherein a difference of optical transmittance between adjacent translucent portions is in the range of 4% ~75%.
The method of claim 7, wherein the sequential removal step uses a method of photolithography.