Method for patterning thin films

• US 6,399,258 B2
• Filed: 01/12/2001
• Issued: 06/04/2002
• Est. Priority Date: 01/14/1999
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smithson, Robert L. W., OʼBrien, Dennis P., Florczak, Jeffrey M.
• Primary Examiner(s): Young, Christopher G.
• Application Number:
  US09/759,794
• Publication Number:
  US 20010006766A1
• Time in Patent Office: 508 Days
• Field of Search: 430/17, 430/9, 430/311, 430/325, 430/326, 430/252, 430/253, 430/257
• US Class Current: 430/17
• CPC Class Codes: B41M 5/262 recording or marking of inorganic surfaces or materials, e.g. glass, metal, or ceramics marking of plastic artifacts with inorganic additives B41M5/267
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 19/009 for use with infrared radiation
• CPC Class Codes: G02B 19/0095 for use with ultraviolet radiation
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G02B 27/0911 Anamorphotic systems
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06
• CPC Class Codes: G03F 1/68 Preparation processes not covered by groups G03F1/20 - G03F1/50
• CPC Class Codes: G03F 7/30 Imagewise removal using liquid means
• CPC Class Codes: G03F 7/3014 combined with ultrasonic means
• CPC Class Codes: G03F 7/34 Imagewise removal by selective transfer, e.g. peeling away
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H05K 3/027 the conductive material being removed by irradiation, e.g. by photons, alpha or beta particles

Abstract

Patterned articles, such as RFID antenna, are made by subablation, a process comprising the steps of:

A. providing a substrate having a coating, such as a metal or metal oxide, and an interface comprising the thin region where the coating and the substrate are closest to each other;

B. exposing at least one part of the total area of the coating to a flux of electromagnetic energy, Such as a focused excimer laser beam, sufficient to disrupt the interface but insufficient to ablate the coating, and

C. removing the parts of the coating in registry with the portion of the interface area that was disrupted, by means such as ultrasonic agitation.

The process has advantages over photo-resist processes in that there is no residual chemical resist left on the product and no undercutting of the pattern or image. It has advantages over laser ablation processes in that higher throughput is possible at the same energy level and there is no microscopic debris left on the product surface.

Claims

1. A method of making an imaged surface comprising:

A. providing a substrate having a coating and an interface comprising the region where the coating and the substrate are closest to each other;

B. exposing at least one part of the total area of the coating to a flux of electromagnetic energy sufficient to disrupt the interface but insufficient to ablate the coating; and

C. removing the parts of the coating in registry with the portions of the interface area that was disrupted.

2. The method of claim 1 in which the substrate is polymeric.

3. The method of claim 2 in which the substrate is selected from the group consisting of polyesters, polycarbonates, polyethylene, polyamides, polyvinylchloride, polystyrene, polypropylene, and polyimides.

4. The method of claim 1 in which the electromagnetic energy is selected from the group consisting of light from a flash lamp and laser radiation.

5. The method of claim 4 in which the electromagnetic energy is laser radiation which is shaped and focused onto the coating surface and has a fluence of between 30 and 99 percent of the ablation threshold fluence.

6. The method of claim 5 in which the laser radiation is shaped to a beam with an approximately rectangular cross section.

7. The method of claim 1 in which the adhesive force between the coating and the substrate is between about 40 and 700 g/cm.

8. The method of claim 1 in which step B comprises exposing at least part of the area of the substrate to electromagnetic radiation in an arrangement in which there is a mask between the substrate and the source of the electromagnetic radiation, the distance between the mask and the substrate being referred to as a path.

9. The method of claim 8 in which the path is no greater than 2 millimeters.

10. The method of claim 1 in which the coating is made of a material selected from the group consisting of metals, oxides, metal alloys, lithium niobate, magnesium fluoride, zinc sulfide, LiTaO₃, calcium fluoride, and titanium nitride.

11. The method of claim 1 in which the coating is an organic material.

12. The method of claim 10 in which:

the metals are selected from the group consisting of copper, silver, nickel, chrominum, tin, gold, indium, and aluminum;

the oxides are selected from the group consisting of indium-tin-oxide, silicon oxide, silicon monoxide, zinc oxide, germanium oxide, niobium oxide, tantalum oxide, and aluminum oxide; and

the metal alloys are selected from alloys of the previously listed metals.

13. The method of claim 1 in which step C comprises a method selected from:

A. treating the coated substrate with ultrasonic vibrations in a fluid medium until the parts of the coating in registry with the disrupted parts of the interface are dislodged from the surface of the substrate;

B. contacting the surface of the coated substrate with an adhesive sufficient to selectively lift the parts of the coating in registry with the disrupted parts of the interface from the coated substrate but insufficient to lift the parts of the coating in registry with parts of the interface not disrupted from the coated substrate; and

C. contacting the surface of the substrate exposed to electromagnetic radiation with a high velocity stream of a benign liquid or gas.

14. The method of claim 1 in which there is a tie layer at the interface, and the parts of the tie layer congruent with the parts of the coating removed in step C are also removed.

15. The method of claim 11 in which the coating comprises an acrylate coating.