Pattern forming method, semiconductor device manufacturing method and exposure mask set
First, a first exposure process is performed using dipole illumination with only a grating-pattern forming region as a substantial object to be exposed. Next, a second exposure process is performed with only a standard-pattern forming region as a substantial object to be exposed. A development process is then performed to obtain a resist pattern. A mask for the first exposure process is such that a light blocking pattern is formed on the whole surface of a standard-pattern mask part corresponding to the standard-pattern forming region. A mask for the second exposure is such that a light blocking pattern is formed on the whole surface of a grating-pattern mask part corresponding to the grating-pattern forming region.
1. A pattern forming method on a resist formed on a predetermined substrate, said resist including adjacent first and second regions to be patterned, said method comprising the steps of:
(a) performing a first exposure process with a first exposure mask using dipole illumination substantially on said first region of said resist, said first exposure mask having a repetition pattern in which a line and space are repeated alternately;
(b) performing a second exposure process with a second exposure mask substantially on said second region of said resist, said second exposure mask having a standard pattern that is a pattern excluding said repetition pattern, said standard pattern at least partially including a connection pattern continuous with said repetition pattern; and
(c) performing a development process on said resist having being subjected to said steps (a) and (b); wherein
said first and second exposure masks each include first and second mask parts corresponding to said first and second regions of said resist, respectively,
said first exposure mask is provided with a pattern for forming said repetition pattern on said first mask part, and a light blocking region on the whole surface of said second mask part, and
said second exposure mask is provided with a pattern for forming said standard pattern on said second mask part, and an extension part of said connection pattern of said standard pattern and a light blocking region on said first mask part, said extension part being provided in a first extension region extending inwardly from a boundary line between said first and second mask parts by a first predetermined amount, said light blocking region being provided on the whole surface of a region excluding said first extension region and a second extension region, said second extension region extending inwardly from an edge line corresponding to an edge position of said pattern for forming said repetition pattern by a second predetermined amount.
2. The pattern forming method according to claim 1 , wherein
said first and second exposure masks each include first and second mask parts corresponding to said first and second regions of said resist, respectively,
said first exposure mask is provided with a pattern for forming said repetition pattern on said first mask part, and a light blocking region on the whole surface of said second mask part, and
said second exposure mask is provided with a pattern for forming said standard pattern on said second mask part, and a light blocking region on the whole surface of said first mask part.
3. The pattern forming method according to claim 1 , wherein
a direction in which said line in said repetition pattern is formed is defined as a first direction, and a direction orthogonal to said first direction is defined as a second direction, and
said first and second predetermined amounts include an amount in view of the amount of edge recession of a pattern for forming said space in said repetition pattern, and the amount of overlay deviation in said first direction between said first and second exposure masks of said steps (a) and (b).
4. The pattern forming method according to claim 3 , wherein
a forming width of said extension part of said connection pattern is equivalent to the sum of a forming width of a pattern for forming said line in said repetition pattern and an amount in view of the amount of overlay deviation in said second direction between said first and second exposure masks of said steps (a) and (b) and the amount of dimensional accuracy tolerance.
5. The pattern forming method according to claim 1 , wherein
said first and second exposure masks each include a transmissive part, a half-tone phase shift mask part transmitting light only at a predetermined ratio and inverting a phase of light being transmitted therethrough, and a light blocking part having a smaller transmission factor than said predetermined ratio,
said second mask part of said first exposure mask is formed at least of said light blocking part in a region excluding a boundary adjacent region between said first and second mask parts,
said first mask part of said second exposure mask is formed at least of said light blocking part in a region excluding said boundary adjacent region.
6. The pattern forming method according to claim 5 , wherein
both of said first and second exposure masks are formed of said half-tone phase shift mask part in said boundary adjacent region.
7. The pattern forming method according to claim 6 , wherein
said first exposure mask is locally widened in forming width in a region adjacent to said second mask part, with respect to a pattern corresponding to said line in said first mask part.
8. The pattern forming method according to claim 1 , wherein
said predetermined substrate including a plurality of substrates classifiable by the wafer, and
said steps (a) and (b) are performed on said plurality of substrates in a changed sequence.
9. The pattern forming method according to claim 1 , wherein
said resist includes a positive type resist.
10. The pattern forming method according to claim 1 , wherein
said repetition pattern includes a first partial repetition pattern in which a line and space are repeated in a first direction and a second partial repetition pattern in which a line and space are repeated in a second direction orthogonal to said first direction, and
said first exposure mask includes first and second partial repetition pattern masks having said first and second partial repetition patterns,
said step (a) comprising the steps of:
(a-1) performing an exposure process with said first partial repetition pattern mask on said resist, under a first illumination condition using dipole illumination in which twin lenses are arranged in said first repetition direction; and
(a-2) performing an exposure process with said second partial repetition pattern mask on said resist, under a second illumination condition using dipole illumination in which twin lenses are arranged in said second repetition direction.
11. A semiconductor device manufacturing method, comprising the steps of:
(a) forming a resist on a semiconductor substrate or an object to be patterned inside said semiconductor substrate;
(b) patterning said resist using a pattern forming method on a resist formed on a predetermined substrate comprising the steps of:
(b1) performing a first exposure process with a first exposure mask using dipole illumination substantially on said first region of said resist to be patterned, said first exposure mask having a repetition pattern in which a line and space are repeated alternately;
(b2) performing a second exposure process with a second exposure mask substantially on a second region of said resist to be patterned, said second exposure mask having a standard pattern that is a pattern excluding said repetition pattern, said standard pattern at least partially including a connection pattern continuous with said repetition pattern; and
(b3) performing a development process on said resist having being subjected to said steps (b1) and (b2); and
(c) patterning said object to be patterned with said resist having been patterned as a mask.
12. An exposure mask set comprising:
a first exposure mask including adjacent first and second mask parts, said first mask part having a repetition pattern in which a line and space are repeated alternately; and
a second exposure mask including first and second mask parts equivalent to said first and second mask parts of said first exposure mask, said second mask part having a standard pattern that is a pattern excluding said repetition pattern, at least part of said standard pattern including a connection pattern for being continuous with said repetition pattern, wherein
said first exposure mask is provided with a light blocking region on the whole surface of said second mask part,
said second exposure mask is provided with a light blocking region on at least part of said first mask part,
said first and second exposure masks each include a transmissive part, a half-tone phase shift mask part transmitting light only at a predetermined ratio and inverting a phase of light being transmitted therethrough, and a light blocking part having a smaller transmission factor than said predetermined ratio, said second mask part of said first exposure mask is formed at least of said light blocking part in a region excluding a boundary adjacent region between said first and second mask parts,
said first mask part of said second exposure mask is formed at least of said light blocking part in a region excluding said boundary adjacent region; wherein
a direction in which said line in said repetition pattern is formed is defined as a first direction, and a direction orthogonal to said first direction is defined as a second direction,
said second exposure mask is provided with an extension art of said connection pattern of said standard pattern and a light blocking region on said first mask part, said extension part being provided in a first extension region extending inwardly from a boundary line between said first and second mask parts by a first predetermined amount, said light blocking region being provided on the whole surface of a region excluding said first extension region and a second extension region, said second extension region extending inwardly from an edge line corresponding to an edge position of said pattern for forming said repetition pattern by a second predetermined amount;
said first and second predetermined amounts include an amount in view of the amount of edge recession of a pattern for forming said space in said repetition pattern, and the amount of overlay deviation in said first direction at the time of exposure using said first and second exposure masks, and
a forming width of said extension part of said connection pattern is equivalent to the sum of a forming width of a pattern for forming said line in said repetition pattern and an amount in view of the amount of overlay deviation in said second direction at the time of exposure using said first and second exposure masks and the amount of dimensional accuracy tolerance.
13. The exposure mask set according to claim 12 , wherein
both of said first and second exposure masks are formed of said half-tone phase shift mask part in said boundary adjacent region.