JPH05243114A - Exposure - Google Patents

Abstract

PURPOSE:To easily form a mask having improved accuracy in pattern diameter control, and to form a complicated transfer pattern. CONSTITUTION:An AZ 1350 resist 12 is applied to an Si substrate 11. Then, i-rays are projected through the mask 13 to be used for formation of a phase shifter, and a phase shifter pattern 12a is formed inside the resist 12. At this time, the amount of exposure is controlled in such a manner that the unexposed part of resist becomes a phase shifter which gives a suitable amount of phase shifting. Further, i-rays are projected, and an exposure pattern 12b is formed inside the resist using a transfer pattern mask 14. Lastly, the pattern is developed, and a resist pattern 15, which will be seen in a residual image resist, is formed on the Si substrate 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photolithography technique, and more particularly to an exposure method for improving resolution and pattern size control accuracy during exposure.

[0002]

2. Description of the Related Art Recently, a phase shift exposure method has been used to form a submicron fine pattern on a resist. The phase shift exposure method is an exposure method for improving the resist pattern transfer accuracy by appropriately rotating a part of the phase of light passing through the mask. Generally, in order to perform phase shift exposure, a phase shifter was formed on a mask, and these masks were used to perform a rotting.

[0003]

In the above-mentioned conventional phase shift exposure method, since the phase shifter is formed on the mask, the mask manufacturing process is complicated, and the transfer pattern and the shifter are formed on the same mask. It was difficult to manufacture a mask having a complicated transfer pattern. Further, since the mask and the phase shifter have a one-to-one correspondence, there is a drawback that the degree of freedom in pattern formation is small at present because the optimum shape of the shifter for the mask is unknown.

An object of the present invention is to provide an exposure method which facilitates the production of a transfer pattern mask and expands the degree of freedom in pattern formation.

[0005]

In order to achieve the above object, in the exposure method according to the present invention, a resist is applied on a substrate and a part of the resist is exposed to change the refractive index of the resist in the exposed part. Then, the pattern is transferred by second exposure.

In addition, a resist is applied on a substrate, a part of the resist is irradiated with ions, then developed to partially remove the resist, and then a second exposure is performed to transfer a pattern. Is.

[0007]

[Operation] In the exposure process of photolithography technology,
By applying a resist on the substrate and exposing a part of the resist, the refractive index of the resist changes in the exposed area. Is formed.

Alternatively, in the exposure step in the photolithography technique, a resist is applied on a substrate, and a part of the resist is ion-irradiated and then developed to partially remove the resist, thereby reducing the film thickness of the resist. Modulation to give a phase shift effect.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a process diagram showing a first embodiment of the present invention.

In FIG. 1A, on the Si substrate 11,
AZ1350 resist 12 is applied. As in (b), i-line is irradiated through the mask 13 for forming the phase shifter to form the phase shifter pattern 12 a inside the resist 12.

At this time, the exposure amount is controlled so that the unexposed portion of the resist becomes a phase shifter which gives an appropriate phase shift amount. Further, in (c), i-line is irradiated to form an exposure pattern 12b inside the resist 12 using the transfer pattern mask 14. When this is developed, the resist pattern 15 seen in the afterimage resist becomes Si as shown in FIG.
It is formed on the substrate 11.

(Embodiment 2) FIG. 2 is a process drawing showing a second embodiment of the present invention. According to the present embodiment, first, as shown in FIG.
In (a), the PMMA resist 22 is applied on the InP substrate 21. Next, as shown in (b), the phase shifter pattern 12a is formed on the resist 22 by performing ion irradiation and development using a focused ion beam device. In this case, the amount of ion exposure is controlled so that the residual image resist portion serves as a phase shifter that gives an appropriate amount of phase shift. Further, in (c), i-line is irradiated to transfer pattern mask 2
At 3, the exposure pattern 22a is formed inside the resist. When this is developed, a resist pattern 24 seen in the developing resist is formed on the InP substrate 21 as shown in (d).

In the above embodiment, the resist AZ1350 is used.
Also, this is an example using PMMA, but in addition to this, KM
R, OSR, LMR-UV, OFPR-800, ODU
Resists such as R-120, EBR-9 and SEL-N can be applied.

[0015]

As described above, according to the present invention,
By forming the phase shifter in the resist mask, the transfer pattern mask can be easily created and a complicated pattern can be formed. Further, since the mask and the phase shifter do not correspond one-to-one, the degree of freedom in pattern formation is expanded.

[Brief description of drawings]

FIG. 1 is a main process chart showing a first embodiment of the present invention.

FIG. 2 is a main process diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 11 Si Substrate 12 Resist 12a Phase Shifter Pattern 12b Exposure Pattern 13 Phase Shifter Forming Mask 14 Transfer Pattern Mask 15 Resist Pattern 21 InP Substrate 22 Resist 22a Exposure Pattern 23 Transfer Pattern Mask 24 Resist Pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI technical display location 7352-4M H01L 21/30 321 7352-4M 361 L

Claims (2)

[Claims] 1. A resist is applied on a substrate, a part of the resist is exposed to change the refractive index of the resist in the exposed part, and then a second exposure is performed to transfer a pattern. Exposure method. 2. A method of applying a resist onto a substrate, irradiating a part of the resist with ions, developing it to partially remove the resist, and then performing a second exposure to transfer the pattern. A characteristic exposure method.