Method for etching protective film, method for producing template, and template produced thereby

• US 10,248,026 B2
• Filed: 09/24/2015
• Issued: 04/02/2019
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Ohtsu, Akihiko
• Primary Examiner(s): Gupta, Yogendra N
• Assistant Examiner(s): Luk, Emmanuel S
• Application Number:
  US14/863,693
• Publication Number:
  US 20160018738A1
• Time in Patent Office: 1,286 Days
• CPC Class Codes: B29C 33/3842 Manufacturing moulds, e.g. shaping the mould surface by machining
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 2237/3341 Reactive etching
• CPC Class Codes: H01J 37/32972 Spectral analysis

Abstract

A substrate having a protective film formed on a front surface and a recess in a back surface opposite the front surface is prepared. A resist pattern is formed on the protective film. The protective film is etched using plasma while applying a bias voltage, using the resist pattern as a mask. The bias voltage is increased according to the manner of decrease in the dielectric constant of a region of the substrate corresponding to a covered region of the front surface at which the protective film is present.

Claims

1. A method for etching a protective film, comprising the steps of:

preparing a substrate having a protective film formed on a front surface and a recess in a back surface opposite the front surface;

forming a resist pattern on the protective film; and

etching the protective film using plasma while applying a bias voltage, using the resist pattern as a mask;

the bias voltage being increased according to the manner of decrease in the dielectric constant of a region of the substrate corresponding to a covered region of the front surface at which the protective film is present in the protective film etching step, resulting from an increase in a percentage of a volume occupied by the recess within a volume of the region of the substrate.

2. A method for etching a protective film as defined in claim 1, wherein:

the bias voltage is increased according to a degree of decrease in the dielectric constant while the dielectric constant is decreasing, and the bias voltage is maintained at a value corresponding to a constant value while the dielectric constant is at the constant value.

3. A method for etching a protective film as defined in claim 1, wherein:

the bias voltage is zero while the dielectric constant is decreasing, then increased to and maintained at a value corresponding to a constant value while the dielectric constant is at the constant value.

4. A method for etching a protective film as defined in claim 1, wherein:

a dimension of the covered region is detected during etching; and

the manner of decrease in the dielectric constant is determined based on the manner of change in the percentage of the recess within the dimension of the substrate corresponding to the covered region.

5. A method for etching a protective film as defined in claim 1, wherein:

plasma components are measured by plasma emission spectroscopy during etching; and

the manner of decrease of the dielectric constant is determined based on the manner of change in the amount of a component which is correlated with etching of the protective film from among the measured components.

6. A method for etching a protective film as defined in claim 1, wherein:

the manner of increase of the bias voltage is determined in advance based on the relationship between etching time and the manner of decrease of the dielectric constant during etching; and

the bias voltage is increased according to the determined manner of increase of the bias voltage.

7. A method for etching a protective film as defined in claim 1, wherein:

the percentage of metal materials within a constituent material of the protective film is 40% or greater.

8. A method for etching a protective film as defined in claim 1, wherein:

the transmittance of the protective film with respect to light having a wavelength of 365 nm is 30% or greater.

9. A method for producing a mold, comprising:

etching a protective film formed on a substrate having a recess on the back surface thereof by a method for etching a protective film as defined in claim 1; and

etching the substrate using the etched protective film as a mask.