Laser Cutting of 3M™ XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723

Introduction

The 3M™ XYZ-Axis Electrically Conductive Adhesive Transfer Tape (ECATT) 9723 is part of a product line of similar materials including 9703, 9705, 9706, 9709, 9709S and 9709SL. The 9723 ECATT product consists of a 60 micron thick acrylic adhesive layer, filled with conductive fillers that conduct electricity through the thickness (Z-axis) and in the plane of the adhesive (X-Y planes). The acrylic adhesive layer itself is protected with 50 micron thick transparent PET easy-release liner on both the top surface and a 75 micron thick blue PET tight-release liner on the bottom surface. A diagram depicting the layers of the 9723 material is shown in Figure 1.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Layers

Figure 1. ECATT 9723 diagram showing PET liners located on top and bottom of the acrylic adhesive layer. PET layers measure 50µm thick on the top and 75µm on the bottom. The acrylic adhesive layer measures 60µm thick.

3M ECATT materials are flexible adhesive tapes. The delicate tacky nature of these materials makes them difficult to process, resulting in deformation of the materials when processed with traditional mechanical methods. The non-contact nature of laser processing overcomes this difficulty, allowing applications with fine geometry and intricate detail. 3M ECATT materials are only suitable for laser cutting, which produces smooth laser-processed edges and minimal heat affected zones without degrading the physical properties of the materials. Other laser processes are not suggested, as they are not conducive to the intended use of these materials. Technology developed by Universal Laser Systems makes it simple to consistently and repeatedly process these materials to a high degree of dimensional accuracy because the non-contact nature of laser processing eliminates material deformation during processing.

Laser Processing Notes

3M 9723 ECATT was tested to assess laser processing compatibility and determine the best system configuration of laser peak power and wavelength. The PET liners absorb 9.3 micron energy more efficiently than other wavelengths, meaning less peak power was necessary to produce good results with minimum heat affects. The acrylic adhesive layer also absorbs the 9.3 micron wavelength efficiently with clean edges free of heat affects. The metallic fillers in the adhesive layer absorb 1.06 micron energy more efficiently than other wavelengths. The combination of 9.3 micron and 1.06 micron laser wavelengths in the MultiWave Hybrid™ system configuration, which combines the two wavelengths into one simultaneous beam, produces a smooth processed edge with minimal heat affect. The PET liners absorb the bulk of the 9.3 micron laser energy leaving the acrylic adhesive layer relatively unaffected by heat affects and discoloration, while the 1.06 micron is transparent to the PET and acrylic adhesive layers, thus only interacting with the metallic fillers. Microscopy images taken at 300x magnification of the processed edge of the 9723 post processing with the liners in place and the liners removed are shown in Figures 2 and 3, respectively. In these images, it is shown that the PET liners contain most of the heat effects and discoloration, while the acrylic adhesive layer itself is relatively free of heat effect and discoloration.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Figure 2

Figure 2. Microscopy image (300x) of the laser processed edge of 3M ECATT 9723 with the PET liners in place. The heat affected zone measures to 150µm.

3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Figure 3

Figure 3. Microscopy image (300x) of the laser processed edge of 3MECATT 9723 with the PET liners removed from the material. The heat affected zone measures to 60µm.

Further inspection of the laser processed material shows that the acrylic adhesive layer is cleanly processed with the 30 watt 9.3 micron CO2 laser source and the metallic fibers in the material are more efficiently cleaved along the processed edge by the addition of the 1.06 micron laser energy. Figures 4 and 5 depict 3D-rendered microscopy images of the processed surfaces shown in Figures 2 and 3. Figure 4 depicts how the PET layer reacts to the laser energy by forming a “wave” of melted material along the top surface of the processed edge (red area). In Figure 5 the PET liners are removed from the material, showing the smooth flat surface and processed edge of the acrylic adhesive layer, free of adverse heat effects (orange region).
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Figure 4

Figure 4. 3D-rendered microscopy image (300x) of the laser processed edge of the ECATT 9723 with the PET liners in place.

3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Figure 5

Figure 5. 3D-rendered microscopy image (300x) of the laser processed edge of the ECATT 9723 with the PET liners removed.

3M 9723 ECATT was also tested with two alternate system configurations (the 9.3 micron laser energy alone and the 10.6 micron laser energy alone) for comparison and determination of the effectiveness of each system configuration. The results of these tests and the MultiWave Hybrid configuration were compared by analyzing the heat effects, quality of the processed edge, and post-processing requirements. The results of the comparison of these system configurations are listed in tabular form in Table 1 and shown photographically in Figure 6. Both alternate system configurations appear viable with some reduction in quality of the results as stated in the comparison.

Table 1 System Configuration Comparison

System ConfigurationHeat-Affected ZoneProcess CharacteristicsPost-Processing Requirements
MultiWave Hybrid™ (Recommended)Minimal heat-affected zone of approximately 150µm The 1.06 micron laser energy in the MultiWave Hybrid configuration as the advantage that the metallic fibers in the material are more efficiently cleaved along the edge of the processed path, resulting in a cleaner, more consistent edge Processing of the 3M 9723 material with either the MultiWave Hybrid, the 9.3 micron or the 10.6 micron configuration did not require additional post-processing
9.3 MicronHeat-affected zone equivalent to MultiWave Hybrid, approximately 150µmWithout the 1.06 micron laser energy, the metallic fibers protrude more from the processed edge
10.6 MicronIncrease heat-affected zone compared to MultiWave Hybrid, approximately 180µmThe configuration has similar results to the 9.3 micro configuration; without the 1.06 micron energy, the metallic fibers protrude more from the processed edge
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Figure 6

Figure 6. Comparison microscopy images (300x) of the processed edge resulting from MultiWave Hybrid processing (left), 9.3 micron processing (center), and 10.6 micron processing (right). The PET liners were left in place for all three samples.

Processing Example

3M ECATT adhesive tape applications requiring fine geometry and intricate detail without degrading the physical properties of the material can be achieved with Universal Laser Systems technology. An example demonstrating the results of laser cutting 3M ECATT 9723 material using the recommended system configuration is shown in Figure 7.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9723 Figure 7

Figure 7. Example of laser cutting 3M ECATT 9723.

Conclusion

3M 9723 ECATT is suitable for laser processing and was extensively tested to determine the most efficient processing system configuration. Through this testing it was determined that laser cutting is viable with this material and a 30 watt 9.3 micron CO2 laser source combined with the 50 watt 1.06 micron fiber laser source using the MultiWave Hybrid Technology is the best system configuration for the processing of this material. The PET liners and acrylic adhesive layer efficiently absorb the 9.3 micron wavelength laser energy, and the metallic fillers in the adhesive layer efficiently absorb the 1.06 micron wavelength to produce a clean smooth processed edge that has minimal heat affected zone and discoloration.