阅读说明：本技术 形成电容掩模的方法 (Method for forming capacitance mask ) 是由 张峰溢 李甫哲 林盈志 林刚毅 于 2018-06-13 设计创作，主要内容包括：本发明公开一种形成电容掩模的方法,包含有下述步骤。首先,形成一块状牺牲图案以及多个长条状牺牲图案于一掩模层上。接着,形成间隙壁于块状牺牲图案以及此些长条状牺牲图案的侧壁。接续,移除此些长条状牺牲图案但保留块状牺牲图案。续之,填入一材料于此些间隙壁之间以及块状牺牲图案上,其中材料具有一平坦顶面。然后,在填入材料之后,形成一图案化光致抗蚀剂,覆盖块状牺牲图案以及此些间隙壁的一部分,但暴露出此些间隙壁的另一部分。(The invention discloses a method for forming a capacitor mask, which comprises the following steps. First, a block sacrificial pattern and a plurality of strip sacrificial patterns are formed on a mask layer. Then, spacers are formed on the block sacrificial patterns and the sidewalls of the strip sacrificial patterns. Then, the strip-shaped sacrificial patterns are removed, but the block-shaped sacrificial patterns are remained. Then, a material is filled between the spacers and on the block sacrificial pattern, wherein the material has a flat top surface. Then, after filling material, a patterned photoresist is formed to cover the block sacrificial pattern and a part of the spacers, but expose another part of the spacers.)

1. A method of forming a capacitive mask, comprising:

forming a block sacrificial pattern and a plurality of strip sacrificial patterns on a mask layer;

forming a spacer on the side walls of the block sacrificial pattern and the strip sacrificial patterns;

removing the strip sacrificial patterns and retaining the block sacrificial patterns;

filling a material between the spacers and on the block sacrificial pattern, wherein the material has a flat top surface; and

after filling the material, a patterned photoresist is formed to cover the block sacrificial pattern and a portion of the spacers, but expose another portion of the spacers.

2. The method of claim 1, wherein the bulk sacrificial pattern and the strip sacrificial patterns form a patterned organic dielectric layer.

3. The method of forming a capacitive mask of claim 1, further comprising:

forming a plurality of cover layers on the block sacrificial patterns and the strip sacrificial patterns.

4. The method of claim 3, wherein the capping layers comprise a dielectric antireflective coating.

5. The method according to claim 3, wherein the step of forming the spacers on the sidewalls of the bulk sacrificial pattern and the strip sacrificial patterns comprises:

depositing a gap wall material to cover the block sacrificial pattern, the strip sacrificial patterns and the mask layer; and

the spacer material is patterned to form the spacers.

6. The method of claim 5, wherein after patterning the spacer material to form the spacers, the cap layers on the elongated sacrificial patterns are removed while the cap layers on the bulk sacrificial patterns remain.

7. The method according to claim 6, further comprising, after removing the strip-shaped sacrificial patterns:

removing the cap layer on the block sacrificial pattern.

8. The method of claim 7, further comprising, after removing said cap layer over said bulk sacrificial pattern:

the block sacrificial pattern is etched back.

9. The method of forming a capacitive mask of claim 1, further comprising, after forming the patterned photoresist:

removing a portion of the material exposed by the patterned photoresist, thereby exposing a portion of the mask layer; and

the patterned photoresist is removed.

10. The method of claim 9, further comprising, after removing the portion of the material exposed by the patterned photoresist:

the exposed portion of the mask layer is removed.

11. The method of claim 1, wherein the mask layer comprises a polysilicon layer, a silicon nitride layer, an organic dielectric layer and a dielectric anti-reflective coating layer stacked from bottom to top.

12. The method of claim 1, wherein said bulk sacrificial pattern directly contacts one of said spacers.

Technical Field

The present invention relates to a method of forming a capacitor mask, and more particularly, to a method of forming a capacitor mask of a dynamic random access memory with a sacrificial pattern.

Background

Random Access Memory (RAM) can read data and write data when used, and the data disappears immediately after power is turned off. Since the data in the random access memory is easily changed, it is generally applied to a personal computer as a memory for temporarily storing data. The random access memory can be further subdivided into "Dynamic" and "Static". Among them, a "Dynamic Random Access Memory (DRAM)" is called "Dynamic (Dynamic) memory" in which 1bit (1bit) of data is stored by 1 transistor plus 1 capacitor, and power must be periodically supplied to maintain the stored contents when the DRAM is used. Dynamic random access memories are simpler in construction (1 transistor plus 1 capacitor to store 1bit of data) resulting in slower access speeds (longer time is required for the capacitor to charge and discharge), but are also less costly and therefore are generally made with higher capacity but lower speed requirements, for example: main memory (main memory) commonly used on the motherboard of a personal computer.

Disclosure of Invention

The present invention provides a method for forming a capacitor mask, which forms a sacrificial pattern above a mask layer to prevent the mask layer from being damaged when the mask layer is patterned into the capacitor mask.

The invention provides a method for forming a capacitor mask, which comprises the following steps. First, a block sacrificial pattern and a plurality of strip sacrificial patterns are formed on a mask layer. Then, spacers are formed on the block sacrificial patterns and the sidewalls of the strip sacrificial patterns. Then, the strip-shaped sacrificial patterns are removed, but the block-shaped sacrificial patterns are remained. Then, a material is filled between the spacers and on the block sacrificial pattern, wherein the material has a flat top surface. Then, after filling material, a patterned photoresist is formed to cover the block sacrificial pattern and a part of the spacers, but expose another part of the spacers.

In view of the above, the present invention provides a method for forming a capacitor mask, which forms a block sacrificial pattern and a plurality of strip sacrificial patterns on a mask layer, forms spacers on the block sacrificial pattern and sidewalls of the strip sacrificial patterns, and then removes the strip sacrificial patterns while leaving the block sacrificial pattern. Therefore, the invention can avoid the damage of the mask layer under the massive sacrificial pattern when the exposed mask layer is etched and patterned to form the mask without an additional manufacturing process.

Furthermore, the invention fills a material between the clearance walls and on the block sacrificial pattern after removing the long strip sacrificial pattern but retaining the block sacrificial pattern, and forms a patterned photoresist covering part material, thereby avoiding the patterned photoresist remaining between the clearance walls.

Drawings

FIG. 1 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention;

FIG. 9 is a cross-sectional view of a method for forming a capacitor mask in accordance with a preferred embodiment of the present invention.

Description of the main elements

10. 20: patterned photoresist

110: masking layer

112: polycrystalline silicon layer

114: silicon nitride layer

116: organic dielectric layer

118. 118 a: dielectric antireflective coating

120: sacrificial pattern layer

120a, 120 c: bulk sacrificial pattern

120 b: strip-shaped sacrificial pattern

130. 130a, 130 b: cover layer

140: spacer wall

140': gap wall material

150: material

d 1: voids

d 2: without clearance wall zone

h: height

P1, P2, P3, P4, P5: in part

S: flat top surface

W1, W2: width of

Detailed Description

The present invention is directed to a method for forming a mask for forming a capacitor mask of a dynamic random access memory, but the present invention can also be applied to patterning other material layers of a dynamic random access memory or other structures of the material layers, wherein fig. 1-9 are schematic cross-sectional views illustrating the method for forming a capacitor mask according to a preferred embodiment of the present invention. As shown in fig. 1, a mask layer 110 is provided. In the present embodiment, the mask layer 110 may include a polysilicon layer 112, a silicon nitride layer 114, an organic dielectric layer 116 and a dielectric anti-reflective coating layer 118 stacked from bottom to top, but the invention is not limited thereto. The mask layer 110 may be, for example, on a substrate (not shown). The substrate (not shown) may be a semiconductor substrate, such as a silicon substrate, a silicon-containing substrate (e.g., SiC), a iii-v substrate (e.g., GaN), a iii-v silicon-on-silicon substrate (e.g., GaN), a graphene-on-silicon substrate (graphene-on-silicon), a silicon-on-insulator (SOI) substrate, or an epitaxial layer-containing substrate. Then, a sacrificial pattern layer 120 and a cap layer 130 are sequentially stacked on the mask layer 110. The sacrificial pattern layer 120 may be, for example, an organic dielectric layer, and the cap layer 130 may be, for example, a dielectric anti-reflective coating, but the invention is not limited thereto. The sacrificial pattern layer 120 may be a single layer or a plurality of layers, and the cap layer 130 may also be a single layer or a plurality of layers. In the present embodiment, the sacrificial pattern layer 120 and the cap layer 130 are only single-layer structures. Then, a patterned photoresist 10 is formed on the cap layer 130 for patterning the underlying sacrificial pattern layer 120 and the cap layer 130.

As shown in fig. 2, a block-shaped sacrificial pattern 120a and a plurality of strip-shaped sacrificial patterns 120b are formed on the mask layer 110. In the present embodiment, the block sacrificial patterns 120a and the strip sacrificial patterns 120b constitute a patterned organic dielectric layer. In the present embodiment, the strip sacrificial patterns 120b are used to transfer the capacitors forming the dram downwards, and the block sacrificial patterns 120a are the peripheral regions of the dram, but the invention is not limited thereto. In detail, the patterned photoresist 10 is transferred to the cap layer 130 and the sacrificial pattern layer 120, so that the cap layer 130 and the sacrificial pattern layer 120 are etched to form a cap layer 130a on the block sacrificial pattern 120a and a plurality of cap layers 130b on the strip sacrificial patterns 120 b. Subsequently, the patterned photoresist 10 is removed.

As shown in fig. 3-4, spacers 140 are formed on the sidewalls of the block sacrificial patterns 120a and the strip sacrificial patterns 120b, and then the strip sacrificial patterns 120b are removed while leaving the block sacrificial patterns 120 c. Further, reference may be made to fig. 3-4 and 9. First, as shown in fig. 3, a spacer material 140' is deposited to conform to cover the block sacrificial patterns 120a, the strip sacrificial patterns 120b and the mask layer 110. The spacer material 140' may be, for example, a nitride layer, but the invention is not limited thereto. The spacer material 140' is patterned to form spacers 140, as shown in part a of fig. 9. In the present embodiment, after the spacer material 140 'is patterned to form the spacers 140, the cap layer 130b on the elongated sacrificial pattern 120b is removed but the cap layer 130a on the block sacrificial pattern 120a is remained, wherein the patterning of the spacer material 140' and the removal of the cap layer 130b on the elongated sacrificial pattern 120b can be performed by different processes. Since the cap layer 130a on the block sacrificial patterns 120a is remained in the embodiment, only the exposed strip sacrificial patterns 120b can be removed, but the block sacrificial patterns 120a remain, as shown in part b of fig. 9. Next, the cap layer 130a on the bulk sacrificial pattern 120a may be removed, as shown in part c of fig. 9. Then, the block sacrificial pattern 120a is etched back to form a block sacrificial pattern 120c, and the block sacrificial pattern 120c has a height h, as shown in fig. 4. Thus, the height h of the block sacrificial pattern 120c can be adjusted by etching back, so that the material (not shown) subsequently covering the block sacrificial pattern 120c and the spacer 140 can have a flat top surface and the thickness of the material (not shown) can be controlled, wherein the material preferably has a thinner thickness to facilitate the manufacturing process control. In the embodiment, the block sacrificial pattern 120c directly contacts one of the spacers 140, but the invention is not limited thereto.

In another embodiment, the spacer material 140' of fig. 3 may be directly patterned and the cap layers 130a and 130b may be removed to form the spacers 140 of fig. 4 and expose the block sacrificial patterns 120a and the strip sacrificial patterns 120 b. Thereafter, etching may be directly performed to completely remove the strip sacrificial patterns 120b and simultaneously form the block sacrificial patterns 120c, due to an etching loading effect (etching loading effect) generated by a width W1 of the block sacrificial patterns 120a being greater than a width W2 of the strip sacrificial patterns 120 b.

As shown in fig. 5, a material 150 is filled between the spacers 140 and on the block sacrificial pattern 120c, wherein the material 150 has a flat top surface S. The material 150 may be, for example, but not limited to, a bottom anti-reflective-coating (BARC). After filling the material 150, a patterned photoresist 20 is formed to cover the bulk sacrificial pattern 120c and a portion P1 of the spacer 140, but expose another portion P2 of the spacer 140, as shown in fig. 6. Since the material 150 of the present invention completely fills the gap d1 between the spacers 140, the gap d1 between the spacers 140 remained after the removal of the photoresist 20 is prevented.

Next, a portion P3 of the material 150 exposed by the patterned photoresist 20 is removed, but another portion P4 of the material 150 covered by the patterned photoresist 20 remains, thereby exposing a portion P5 of the mask layer 110, as shown in fig. 7. Subsequently, the patterned photoresist 20 is removed.

Thereafter, the exposed portion P5 of the mask layer 110 is patterned, i.e., the mask layer 110 exposed by the gap d1 between the spacers 140 is removed, as shown in fig. 8, thereby forming a portion of the capacitor mask, which is formed by patterning the mask layer 110. In the present embodiment, only the uppermost layer (i.e., the DARC layer 118) of the mask layer 110 is patterned, and a patterned DARC layer 118a is formed first, and then the pattern of the DARC layer 118a is transferred to the underlying material layer, but the invention is not limited thereto. By disposing the block sacrificial pattern 120c on the mask layer 110 without the spacer region d2, the mask layer 110 without the spacer region d2 is prevented from being removed or damaged when patterning the exposed portion P5 of the mask layer 110. In addition, the present invention can form the block sacrificial pattern 120c without an additional process, thereby achieving the function.

In summary, the present invention provides a method for forming a capacitor mask, which forms a block sacrificial pattern and a plurality of strip sacrificial patterns on a mask layer, forms spacers on the block sacrificial pattern and sidewalls of the strip sacrificial patterns, and then removes the strip sacrificial patterns while leaving the block sacrificial pattern. Therefore, the invention can avoid the damage of the mask layer under the massive sacrificial pattern when the exposed mask layer is etched and patterned to form the mask without an additional manufacturing process.

Furthermore, the invention fills a material between the clearance walls and on the block sacrificial pattern after removing the long strip sacrificial pattern but retaining the block sacrificial pattern, and forms a patterned photoresist covering part material, thereby avoiding the patterned photoresist remaining between the clearance walls.

Furthermore, in an embodiment of the present invention, the block sacrificial pattern is etched back before the material is filled, so that the material covering the block sacrificial pattern and the spacer has a flat top surface and the thickness of the material can be controlled.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in the claims of the present invention should be covered by the present invention.