Sub-resolution assist features

Patent metadata

Field	Value
Publication number	US-11829066-B2
Application number	US-202117240265-A
Country	US
Kind code	B2
Filing date	Apr 26, 2021
Priority date	Jul 23, 2019
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

Methods of semiconductor device fabrication are provided. In an embodiment, a method of semiconductor device fabrication includes receiving a first mask design comprising a first mask function, determining a transmission cross coefficient (TCC) of an exposure tool, decomposing the TCC into a plurality orders of eigenvalues and a plurality orders of eigenfunctions, calculating a kernel based on the plurality orders of eigenvalues and the plurality orders of eigenfunctions; and determining a first sub-resolution assist feature (SRAF) seed map by convoluting the first mask function and the kernel.

First claim

What is claimed is:

1. A method, comprising:
receiving a mask design comprising a mask function;
providing an exposure tool;
determining a transmission cross coefficient (TCC) of the exposure tool;
decomposing the TCC into a plurality orders of eigenvalues (λ i ) and a plurality orders of eigenfunctions (ϕ i (x,y));
calculating a kernel (Ω(x,y)) based on the following mathematical formula:

Ω
⁡
(

x
,
y

)

=

R
⁢

e
[

∑

i
=
1

N

λ
i

⁢

ϕ
i
*

(

0
,
0

)

⁢

ϕ
i

(

-
x

,

-
y

)

]

and
determining a sub-resolution assist feature (SRAF) seed map (Γ(x,y)) by convoluting the kernel (Ω(x,y)) and the mask function.

2. The method of claim 1 ,
wherein the exposure tool comprises a set of exposure conditions,
wherein the determining of the TCC is based on the set of exposure condition.

3. The method of claim 2 , wherein the set of exposure conditions comprises an illumination intensity of the exposure tool, a numerical aperture of the exposure tool, a thickness of a resist stack to be patterned, or a range of an aberration.

4. The method of claim 2 , further comprising storing the kernel (Ω(x,y)) in a memory medium, wherein the kernel is unique to the set of exposure conditions.

5. The method of claim 4 , further comprising retrieving the stored kernel (Ω(x,y)) for reuse.

6. The method of claim 1 ,
wherein the mask design is assumed to be implemented as an ideal mask,
wherein the mask function includes an X-X component (a xx (x,y)), an X-Y component (a yy (x,y)), a Y-X component (a yx (x,y)), and a Y-Y component (a yy (x,y)),
wherein the plurality orders of eigenvalues include a first plurality orders of X-X interaction eigenfunctions (ϕ i xx (x,y)), a second plurality orders of X-Y interaction eigenfunctions (ϕ i yy (x,y)), a third plurality orders of Y-X interaction eigenfunctions (ϕ i yx (x,y)), and a fourth plurality orders of Y-Y interaction eigenfunctions (ϕ i yy (x,y)),
wherein the kernel (Ω(x,y)) includes an X-Y kernel component (Ω xy (x,y)), a Y-X kernel component (Ω yx (x,y)), and a Y-Y kernel component (Ω yy (x,y)) respectively expressed by the following mathematical formulae:

Ω

X
⁢
X

(

x
,
y

)

=

Re
[

∑

i
=
1

N

λ
i

⁢

ϕ
i

XX
*

(

0
,
0

)

⁢

ϕ
i

X
⁢
X

(

-
x

,

-
y

)

]

,

Ω

X
⁢
Y

(

x
,
y

)

=

Re
[

∑

i
=
1

N

λ
i

⁢

ϕ
i

XY
*

(

0
,
0

)

⁢

ϕ
i

X

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Yamazoe Kenji
• Lei Junjiang
• Peng Danping

Classifications

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• G03F1/70 Primary

  Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging · CPC title

• G03F1/42

  Alignment or registration features, e.g. alignment marks on the mask substrates · CPC title

• G03F1/44

  Testing or measuring features, e.g. grid patterns, focus monitors, sawtooth scales or notched scales · CPC title

• G03F7/2004

  characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light · CPC title