Process of depositing a metallic pattern on a medium

Abstract

Process of depositing a metallic pattern on a medium, said process comprising: generating pulsed laser beams from a pulsed laser source, wherein the laser beams have a wavelength for which the medium is substantially transparent, focussing the laser beams onto a target layer comprising inorganic particles, dispersed in a laser light degradable/combustible organic matrix, said target layer producing ejecta in response to an interaction of said laser beams and said target layer, accumulating at least a portion of said ejecta on said medium within the desired pattern, providing the pattern by electroless metal plating. The invention further relates to a transparent medium comprising a metallic pattern wherein the adhesion between the metallic pattern and the medium is at least 5N/cm.

Claims

1. A process for depositing a metallic pattern on a medium, wherein the process comprises: i) generating pulsed laser beams from a pulsed laser source, wherein the laser beams have a wavelength for which the medium is substantially transparent to thereby provide a laser-transparent medium, ii) guiding the laser beams through the laser-transparent medium and focusing the laser beams which are guided through the laser-transparent medium onto a target layer comprising inorganic particles dispersed in a laser light degradable/combustible organic matrix thereby causing the target layer to produce ejecta in response to an interaction of the laser beams and the target layer, iii) accumulating at least a portion of the ejecta transferred backwardly on the medium within the desired pattern, iv) providing the pattern by electroless metal plating.

2. The process according to claim 1, wherein the concentration of the inorganic particles in the organic matrix is between 20 and 80 wt %.

3. The process according to claim 1, wherein the target layer comprising inorganic particles is a casted film.

4. The process according to claim 1, wherein the organic matrix is a thermoset polymer.

5. The process according to claim 4, wherein the organic matrix comprises less than 5 wt % of aromatic groups based on the total weight of the organic matrix.

Description

EXAMPLES

(1) In the examples below the target layer comprises inorganic particles (A1-A5) and organic matrices (R1, R2) A1 Bismuth oxide Bi.sub.2O.sub.3 A2 Copper oxide (Cu(I)O or, Cu(II)O A3 Iron oxide Fe.sub.2O.sub.3 A4 Copper iodide (Cu (I)I A5 Metallic salts (M-acetate, where M is Pd, or Cu) R1 Neorad DSM-AGI Aliphatic urethane acrylate diluted with 20% DPGDA including. R2 Irgacure 819 Photoinitiator Ciba Specialty Chemicals

(2) As the substantially transparent medium sheets of the following materials are used: P1 Bionate 55D DSM Thermoplastic Polycarbonate Urethane P2 Arnite A06 101 DSM Polyether-ester-terephthalate P3 Xantar 18R Mitsubishi Engineering-Plastics Corporation Polycarbonate P4 RILSAN Clear G350 ARKEMA Polyamide All amounts are in parts per weight.
Method of Preparation of the Target Layer (TL)

(3) Using a Ultra Turrax homogenizer of IKA a number of coating layers including absorber additives where produced. TL02-TL06 were produced, as well as a comparative example TL01. The compositions of the TLs are given in Table 1. The homogenizer speed was 1000 rounds/min.at room temperature.

(4) TABLE-US-00001 TABLE 1 Laser-marking additive Compound Resin (R1) UV-Initiator(R2) Absorber TL01 = Comparative Copper plate Metal TL 02.0 58 2 40 (A1) TL 03.0 58 2 40 (A2) TL 03.1 48.3 1.7 50 (A2) TL 03.2 38.7 1.3 60 (A2) TL 04.0 58 2 40 (A3) TL 04.1 48.3 1.7 50 (A3) TL 04.2 38.7 1.3 60 (A3) TL 05 58 2 40 (A4) TL 06 58 2 40 (A5)
Method of Curing the Target Layer.

(5) Coatings where applied to a glass substrate using a coating applicator bar from Byk with a predefined layer thickness. Following these samples where cured using a UV-H lamp under N2 atmosphere. The applied energy was 2 joule/cm.sup.2. After the UV curing step a thermal post cure was done in a convection oven at 80 C. for 24 hours.

(6) Method of Transferring the Metal Seeds from the Cured TL to the Medium

(7) Through the transparent medium a pattern was written on the coating layer compositions using a diode pumped Nd:YAG IR laser from Trumpf, type Vectomark Compact, wavelength 1064 nm. The target layer was positioned against the medium.

(8) Method of Plating the Transparent Medium

(9) The transparent medium was plated using a commercial available plating bath (Enthone Inc.) at 48 C. receipt as described in table 2.

(10) TABLE-US-00002 TABLE 2 Standard recipe for the preparation of a Copper plating bath. Make up concentration Product name [mL/L] Content ENPLATE LDS CU400 A PC 80 Copper/Formaldehyde/ Stabilizers ENPLATE LDS CU400 B 160 Complexer ENPLATE LDS CU400 C PC 10-15 NaOH/Stabilizers ENPLATE LDS CU400 D 20-35 NaOH/Accelerators ENPLATE LDS CU400 E 0.125 Wetting Agent
Evaluation of Plating Performance.

(11) The marking speed (v [mm/sec]) and frequency (f [kHz]) are varied at given power (p [%]) and focal distance (z=0 [in focus]. An evaluation of the plating performance with respect to copper growth on the surface of the plastic substrate and adhesion ranging from excellent (+++++) to poor ()is given in table 3.

(12) The plating performance is judged visually by observing the deposited amount of copper on the laser activated area and the edge sharpness.

(13) The adhesion performance was rated by a nail scratch test. An evaluation of the plating performance with respect to copper grow on the surface of the plastic substrate and adhesion ranging from excellent (+++++) to poor ()is given in table 3.

(14) TABLE-US-00003 TABLE 3 Plating performance and adhesion performance. Adhesion Used Target Plating Adhesion strength Example medium layer performance performance (N/cm) Comp. P1 Cu plate +++ <1 Ex. TL01 1 P1 TL02 ++++ +++ 3-4 2 P1 TL03.0 +++++ +++++ 5 3 P1 TL03.1 +++++ ++++++ 6-8 4 P1 TL03.2 +++++ +++++++ 10 5 P1 TL04.0 +++++ +++++ 5 6 P1 TL04.1 +++++ +++++++ 6-8 7 P1 TL04.2 +++++ ++++++++ 10 8 P1 TL05 +++++ +++++ 5 9 P1 TL06 +++++ ++ 3 10 P2 TL02 +++++ +++ 34 11 P2 TL03.0 +++++ +++++ 5 12 P2 TL04.0 +++++ +++++ 5 13 P2 TL05 +++++ +++++ 5 14 P2 TL06 +++++ ++ 3 15 P3 TL02 +++++ +++ 3-4 16 P3 TL03.0 +++++ +++++ 5 17 P4 TL03.0 +++++ +++++ 5

(15) The adhesion strength was also measured with a quantitative test method for adhesion of plated LDS-MIDs. A peel test according to DIN 51 221, part 1 was carried out using a Zwick/Roell Peel Testing machine. The test was performed at 20 C. With the prior art sample the adhesion was below 1 N/cm.

(16) The samples made by the process of the present invention have an adhesion strength well above 5 N/cm and values above 10 N/cm could be obtained as well. The invention further relates to a transparent medium comprising a metallic pattern wherein the adhesion between the metallic pattern and the medium is at least 1 N/cm, preferably at least 5 N/cm and more preferably at least 10 N/cm.