Secondary electron generating composition

Patent metadata

Field	Value
Publication number	US-11487199-B2
Application number	US-202016803871-A
Country	US
Kind code	B2
Filing date	Feb 27, 2020
Priority date	Mar 25, 2014
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

The present invention relates to a resist composition, especially for use in the production of electronic components via electron beam lithography. In addition to the usual base polymeric component (resist polymer), a secondary electron generator is included in resist compositions of the invention in order to promote secondary electron generation. This unique combination of components increases the exposure sensitivity of resists in a controlled fashion which facilitates the effective production of high-resolution patterned substrates (and consequential electronic components), but at much higher write speeds.

First claim

The invention claimed is:

1. A resist composition comprising:
(i) a secondary electron generator, which increases the radiation-sensitivity of the resist composition, comprising a compound having an effective atomic number (Z eff ) greater than or equal to 40; and
(ii) a base component which is a radiation-sensitive resist material that undergoes a change upon exposure to radiation, such that radiation-exposed base component has different solubility properties to unexposed base component,

wherein the effective atomic number (Z eff ) is calculated as:
Z eff =Σa i Z i

where Z i is the atomic number of the ith element in the compound, and a i is the fraction of the sum total of the atomic numbers of all atoms in the compound constituted by said ith element, and wherein the secondary electron generator comprises a d-block, p-block, or f-block metal species.

2. The resist composition as claimed in claim 1 , wherein the resist composition is an electron beam resist composition and/or a photoresist composition.

3. The resist composition as claimed in claim 1 , wherein the secondary electron generator or compound(s) thereof has a Z eff of at least 20 units higher than the resist material, a density greater than that of the resist material, or a density greater than or equal to 2.5 g/cm 3 .

4. The resist composition as claimed in claim 1 , wherein the secondary electron generator is or comprises a metal compound comprising a metal species having an oxidation state of +1 or higher and an atomic number (Z) greater than or equal to 57.

5. The resist composition as claimed in claim 1 , wherein the secondary electron generator is soluble in the resist composition.

6. The resist composition as claimed in claim 1 , wherein the resist material is or comprises a compound having an effective atomic number (Z eff ) less than or equal to 10.

7. The resist composition as claimed in claim 1 , wherein the resist composition is a resist composition comprising:
(i) a resist material having an effective atomic number (Z eff ) less than or equal to 15 and having a density less than or equal to 2 g/cm 3 ;
(ii) a secondary electron generator comprising a compound having an effective atomic number (Z eff ) greater than or equal to 40 and a density greater than or equal to 2.5 g/cm 3 ; and
(iii) optionally a cross-linking agent;

wherein the secondary electron generator is soluble in the resist composition and the resist composition is a solution.

8. The resist composition as claimed in claim 7 , wherein the Z eff excludes any solvates having a boiling point less than or equal to 150° C. at 100 kPa pressure.

9. The resist composition as claimed in claim 1 , wherein the resist composition is free of any particulate matter.

10. The resist composition as claimed in claim 1 , wherein the resist material has a density less than or equal to 2.0 g/cm 3 , and a Z eff less than or equal to 15.

11. The resist composition as claimed in claim 1 , wherein the secondary electron generator is a metal halide.

12. The resist composition as claimed in claim 11 , wherein the metal halide is part of a complex.

13. The resist composition as claimed in claim 1 , wherein the secondary electron generator is a gold-based compound or a mercury-based compound.

14. The resist composition as claimed in claim 1 , wherein the resist material acts as a vehicle for the secondary electron generator.

15. The resist composition as claimed in claim 1 , wherein the resist material is or comprises a non-polymeric complex.

16. The resist composition as claimed in claim 1 , wherein the Z eff excludes any solvates having a boiling point less than or equal to 150° C. at 100 kPa pressure.

17. A method of preparing a resist composition, the method comprising mixing together:
(i) a secondary electron generator, which increases the radiation-sensitivity of the resist composition, comprising a compound having an effective atomic number (Z eff ) greater than or equal to 40; and
(ii) a base component which is a radiation-sensitive resist material that undergoes a change upon exposure to radiation, such that radiation-exposed base component has different solubility properties to unexposed base component,

wherein the effective atomic number (Z eff ) is calculated as:
Z eff =Σa i Z i

where Z i is the atomic number of the ith element in the compound, and a i is the fraction of the sum total of the atomic numbers of all atoms in the compound constituted by said ith element, and wherein the secondary electron generator comprises a d-block, p-block, or f-block metal species.

Assignees

• Univ Manchester

Inventors

• Lewis Scott
• Yeates Stephen
• Winpenny Richard

Classifications

• H10P54/00

  Cutting or separating of wafers, substrates or parts of devices · CPC title

• H10P50/692

  characterised by their composition, e.g. multilayer masks or materials · CPC title

• H10P50/642

  Chemical etching · CPC title

• H10W72/072

  of bump connectors · CPC title

• H10W74/15

  on active surfaces of flip-chip devices, e.g. underfills · CPC title