Kapton surfaces

Surface Activation of PMR-15 by sulfonation has been described.17 BMI surfaces were made hydrophilic by surface oxidation with UVOCS and/or depositing a sol gel layer of Si02.18 Kapton surfaces were activated with a UVOCS cleaner or by air-plasma. Their water contact angle fell from 64° to 0°. 

Figure 6. RBS profile of a Kapton surface after Pd seeding and brief exposure to an electroless Cu plating bath.

Fig. 3. Scanning electron micrograph of a Kapton polyimide surface that was exposed to the low Earth orbital ram environment for 40 hours on the STS-46 space shuttle mission. The smooth portion of the Kapton surface was covered during exposure and therefore shows no erosion. The rougher portion of the surface shows the topography and extent of erosion (6 /rm deep) resulting from the exposure.

Fig. 21. Time-of-flight distributions of CO2 exiting a continuously oxidized Kapton surface following exposure to pulses of five hyperthermal argon beams whose average translational energies aie shown. The distributions are normalized with respect to the respective incident beam intensity.

Polymers. Ion implantation of polymers has resulted in substantial increases of electrical conductivity (140), surface hardness (141), and surface texturing (142). A four to five order of magnitude increase in the conductivity of polymers after implantation with 2 MeV Ar ions at dose levels ranging from 10 -10 ions/cm has been observed (140). The hardness of polycarbonate was increased to that of steel (141) when using 1 MeV Ar at dose levels between 10 -10 ions/cm. Conductivity, oxidation, and chemical resistance were also improved. Improvements in the adhesion of metallizations to Kapton and Teflon after implantation with argon has been noted (142). 

An all aromatic polyetherimide is made by Du Pont from reaction of pyromelUtic dianhydride and 4,4 -oxydianiline and is sold as Kapton. It possesses excellent thermal stabiUty, mechanical characteristics, and electrical properties, as indicated in Table 3. The high heat-deflection temperature of the resin limits its processibiUty. Kapton is available as general-purpose film and used in appHcations such as washers and gaskets. Often the resin is not used directly rather, the more tractable polyamide acid intermediate is appHed in solution to a surface and then is thermally imidi2ed as the solvent evaporates. 

As stated, the capability of plasma deposits to reduce the access of water to corrosion-sensitive surfaces may be an important motivation for their application in corrosion protection. In order to study this property, Kapton polyimide film was selected as the substrate because of its high inherent permeability to water and its ability to resist elevated temperatures. The response of Kapton film overcoated by PPHMDSO to the permeation of water vapor is shown in Fig. 1. Clearly, the presence of the organo-silicone plasma film greatly reduces water permeation. The magnitude of the effect is much enhanced when plasma polymers are produced at high T and p. 

Fig. 22 Images and data representing development and application of DLS on a chip a one iteration in the design of a microfluidic DLS fabricated from aluminum with the surface anodized black to reduce surface reflections b image of a microfluidic chip that integrates polymer synthesis with DLS. The machined channels have been covered by a Kapton sheet fixed with adhesive c data for temperature depended micelle formation of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (Pluronic P85) at 2% by volume in water. (Derived from [106] with permission)...

An improved process and equipment for cast PTFE films have been developed, which have considerably higher productivity than the method and equipment described above.14 The process essentially uses a vertical coater with multiple stages. The carrier belt has to be made from a material of low thermal mass which can tolerate repeated exposure to the sintering temperature and has surface properties such that it can be wetted by the dispersion, yet the film can be stripped without being stretched. There are several possible belt materials, but KAPTON H (DuPont) was found to be particularly suitable because of its heat resistance, dimensional stability, and surface characteristics.14 The production speeds used in this process are 3 to 10 m/rnin (9 to 30 I t/min). 

We report herein LPD titania films deposited on three kinds of polyimides two high-temperature polyimide resins (PMR-15 and Kapton ) and a bismaleimide glass fiber composite (BMI). We have examined different solution conditions and different surface priming strategies. We have also learned to minimize film cracking by carefully controlling the drying process. 

LPD films of Ti02 on BMI and on Kapton were stable to sonication in water and could not be removed by a standard tape test. Figure 2 shows cross-sectional SEM of samples of BMI and Kapton with surface oxide films ranging in thicknesses from 200-700 nm. The thickness of the titania layer is independent of the activation of the surface or the kind of polymer. The thicker films (Figure 2b and 2d) are comparable ( 20%) to those reported on sulfonate-monolayers (400 nm).12 Thinner films (Figure 2a and 2c) were somewhat thicker than those reported on a clean silicon wafer (200-300 nm vs. 80 nm), likely due to variability in the time needed for the onset of film deposition. 

The following commercial polymeric substrates have been investigated low density polyethylene (PE, Dow Chemical Canada Inc.) polyimide (PI, DuPont Kapton H), polytetrafluoroethylene (PTFE, DuPont Teflon), polycarbonate (PC, Mobay Corp.) and surface-lubricated (with glycerol ester) polyvinylchloride (FVC, Canadian Occidental Petroleum Ltd). After plasma treatment, the samples were exposed to ambient atmosphere for 10 - 30 minutes while being transferred to the following... 

Polyimide KAPTON films were irradiated using a Lambda-Physik EMG200 Excimer laser tuned to 193 nm radiation (ArF). The samples were treated in air, at different fluences all received 10 shots at the repetition rate of 10 Hz. Surface analysis of the different samples was performed using an ESCA-201 system (SSL) with an x-ray microspot facility (150 nm). 

Kapton polyimide has been widely used in the electronic industry because of its low dielectric constant, good mechanical properties and high thermal stability. Many applications require good adhesion between Kapton polyimide film and metal. Various processes to improve adhesion of metal to Kapton polyimide have been reported in the literature. DeAngelo et al., (D describe a process to form metal oxides on the surface of polyimide to improve adhesion. Other efforts to improve adhesion of a metal layer involve roughening of the surface of polyimide substrate by methods such as cathodic sputtering (2), chemical attack (2., 1), and reactive ion etching (1,4). 

We have recently modified the Krause process by incorporating a heat treatment step which results in a novel process for surface texturing of Kapton polyimide (Somasiri, N. L. D. Speckhard, T. A. U. S. Patent Applied For). When the textured polyimide is subsequently metallized, again using the Krause process, good adhesion is obtained after exposure to the solder float test. 

Surface topography of Kapton polyimide as-received, seeded with copper, after the 450°C heat treatment, and after removal of copper oxide by acid etching was examined by scanning electron microscopy. Cross-sectional analysis of Kapton seeded with copper and after 450°C heat treatment was carried out by transmission electron microscopy. 

Kapton films reduced for 15 seconds in the above benzil bath, followed by immersion in 0.05 M PdCl2 / DMF solution have a 45 10 percent charge transfer efficiency for Pd deposition based on the amount of radical-anion form available at the surface. Increasing the amount of film reduction (> 30 sec immersion in the reducing bath) results in increased metal deposition and a visibly darkened surface after exposure to the metal complex solution. Highly... 

Figure 5. RBS profile for a Kapton film prepared by reducing for 15 sec in a 5 percent reduced benzil/ACN solution followed by a 30 sec immersion in a 0.05 M PdCl2/DMF solution shows the presence of a Pd metal deposit at the polyimide surface.

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