Described herein is an improved process for electroplating a conductive metal layer to the surface of a nonconductive material comprising pretreating the material with a carbon black dispersion followed by a graphite dispersion before the electroplating step.
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0. 25. A liquid disperson suitable for use in enhancing the electroplating of a nonconducting surface comprised of:
(a) conductive graphite particles having an average particle diameter of less than about 1.5 microns in said dispersion; (b) an effective dispersing amount of a surfactant which is compatible with said conductive graphite; (c) optionally, a sufficient amount of at least one alkaline hydroxide to raise the pH of said liquid dispersion in the range from about 9 to 14; and (d) liquid dispersing medium, wherein the amount of conductive graphite is sufficient to coat substantially all of said nonconducting surface and is less than about 4% by weight of said liquid dispersion and wherein said liquid dispersion contains less than about 10% by weight solids constituents.
22. A metal-plated nonconductive surface covered with a deposit of a substantially continuous layer of carbon black having an average particle diameter of less than about 3.0 microns thereon and a layer of conductive graphite having an average particle diameter of less than about 1.5 microns deposited over said carbon black deposit and underlying the plated on metal.
1. A process for electroplating a conductive metal layer to the surface of a nonconductive material, comprising the following steps:
(a) contacting said nonconductive surface with a liquid carbon black dispersion comprising: (1) carbon black particles having an average particle diameter of less than about 3.0 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said carbon black; and (3) a first liquid dispersing medium, wherein the amount of carbon black is sufficient to coat substantially all of said nonconducting surfaces and is less than about 4% by weight of said liquid carbon black dispersion; (b) separating substantially all of said first liquid dispersing medium from said carbon black particles, whereby said particles are deposited on said nonconductive surface in a substantially continuous layer; and (c) contacting said carbon black-coated nonconductive surface with a liquid conductive graphite dispersion comprising: (1) conductive graphite particles having an average particle diameter of less than about 1.5 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said conductive graphite; and (3) a second liquid dispersing medium, wherein the amount of conductive graphite is less than about 4% by weight of said liquid conductive graphite dispersion; (d) separating substantially all of said second liquid dispersing medium from said conductive graphite particles, whereby said particles are deposited on said carbon black-coated nonconductive surface; and (e) electroplating a substantially continuous conductive metal layer over the deposited carbon black layer and the deposited conductive graphite layer and said nonconductive surface.
2. The process of
3. The process of
4. The process of
6. The process of
7. The process of
8. The process of
9. The process of
10. The process for electroplating the walls of through holes in a laminated printed wiring board comprised of at least one nonconducting layer laminated to at least two separate conductive metal layers, said process comprising the steps:
(a) contacting said printed wiring board having said through holes in a bath of a liquid carbon black dispersion comprised of: (1) carbon black particles having an average particle diameter of less than about 3.0 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said carbon black; and (3) a first liquid dispersing medium wherein the amount of carbon black is sufficient to coat substantially all of said nonconducting surfaces and is less than about 4% by weight of said liquid carbon black dispersion; (b) separating substantially all of the liquid dispersing medium from said dispersion, thereby depositing said carbon black particles is substantially continuous layer on said nonconducting portions of said hole walls; and (c) contacting said carbon black-coated printed wiring board with a liquid conductive graphite dispersion comprising: (1) conductive graphite particles having an average particle diameter of less than about 1.5 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said conductive graphite; and (3) a second liquid dispersing medium, wherein the amount of conductive graphite is less than about 4% by weight of said liquid conductive graphite dispersion; (d) separating substantially all of said second liquid dispersing medium from said conductive graphite particles, whereby said particles are deposited on said printed wiring board; (e) microetching said metal layers of said printed wiring board to remove any deposited carbon black and graphite therefrom; and (f) electroplating a substantially continuous conductive metal layer over the deposited carbon black layer and the deposited conductive graphite layer on said nonconductive portions of said hole walls, thereby electrically connecting said metal layers of said printed wiring board.
11. The process of
12. The process of
13. The process of
14. The process of
18. The process of
19. The process of
0. 20. A nonconductive surface covered with a deposit of a substantially continuous layer of carbon black having an average particle diameter of less than about 3.0 microns thereon and a layer of conductive graphite having an average particle diameter of less than about 1.5 microns deposited over said carbon black deposit.
21. The A nonconductive surface of
23. The metal-plated nonconductive surface of
0. 26. The dispersion of
0. 27. The dispersion of
0. 28. The dispersion of
0. 29. The dispersion of
conductive graphite having an average particle diameter about 0.05-0.8 microns: 0.1-4% by weight surfactant: 0.01-4% by weight alkaline hydroxide: 0-1% by weight water: Balance.
0. 30. The dispersion of
conductive graphite having an average particle diameter of about 0.01-0.4 microns: 0.2-2% by weight phosphate ester anionic surfactant: 0.05-2% by weight potassium hydroxide: 0.4-0.8% by weight water: Balance.
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This application is a continuation-in-part application of U.S. patent application Ser. No. 07/694,517, filed on May 1, 1991, carbon black graphite dispersion in a proportion sufficient to increase the pH of the resulting graphite-containing dispersion to between about 10 9 and 14, and preferably between about 10 and about 12.
Following is a typical formulation of a suitable aqueous alkaline graphite dispersion showing the general range of proportions as well as the preferred range of proportions for the various components:
| Component | General Range | Preferred Range | |
| Graphite | 0.1-4% by wt. | 0.15-2% by wt. | |
| Surfactant | 0.01-4% | 0.05-2% | |
| Alkaline Hydroxide | 0-1% | 0.4-0.8% | |
| Water | Balance | Balance | |
The liquid graphite dispersion is typically placed in a suitably agitated vessel and the printed wiring board to be treated is immersed in, sprayed with or otherwise contacted with the liquid dispersion. The temperature of the liquid dispersion in an immersion bath is maintained in the range of between about 15°C C. and about 35°C C. and preferably between about 20°C C. and about 30°C C., while the conditioned printed wiring board is immersed therein. The period of immersion generally ranges from about 1 to 10, and preferably from about 3 to 5 minutes. During immersion, the liquid graphite-containing dispersion coats the carbon black layer which was previously applied. The immersed board is then removed from the liquid graphite dispersion bath.
The board is then subjected to a step where substantially all (i.e., more than about 95% by weight) of the water in the applied dispersion is removed and a dried graphite deposit is left in the holes over the carbon black deposit and on other exposed surfaces of the non-conducting layer. This may be accomplished by several methods such as by evaporation at room temperature, by a vacuum, by heating the board for a short time at an elevated temperature, or by an air knife, or by other equivalent means. Heating at an elevated temperature is the preferred method. Heating is generally carried out for between about 30 seconds and 45 minutes at a temperature of from about 75°C to 120°C C., more preferably from about 80°C to 98°C C. To ensure sufficient coverage of the hole walls, the procedure of immersing the board in the liquid graphite dispersion and then drying may be repeated one or more times.
The board is now completely coated with the carbon black and the graphite dispersions. These dispersions are not only coated on the drilled hole surfaces, which is desirable, but also entirely coat the copper plate or foil surfaces which is undesirable. Thus prior to many subsequent operations all carbon black and graphite must be removed from the copper plate or foil surfaces.
The further removal of excessive graphite and/or carbon black specifically from the outer copper surfaces including, especially, the rims of the drilled holes while leaving the coating intact on the glass fibers and epoxy surface of the hole walls, may be achieved by the employment of a microetch bath. Generally, this treatment is carried out at a temperature of about 20°C to 30°C C. for 35 seconds to about 3 minutes. One suitable sodium persulfate-based microetch is "BLACKHOLE MICROCLEAN I" available from Olin Hunt Specialty Products, Inc. This product is preferably combined with sufficient sulfuric acid to make a microetch bath containing 100-300 grams of sodium persulfate per liter of deionized water and about 1 to 10% by weight sulfuric acid. The mechanism by which this microetch works is by not attacking the carbon black material or the graphite material deposited on the copper foil directly, but rather to attack exclusively the first few atomic layers of copper directly below which provides the adhesion for the coating. Hence, the fully coated board is immersed in the microetch solution to "flake" off the carbon black and the graphite from the copper surfaces in the form of micro-flakelets. These micro-flakelets are removed from the microetch bath either by filtration through a pump or via a weir type filter arrangement commonly used in the PWB industry. The liquid carbon black dispersion, the liquid graphite dispersion, the microetch treatment, and the intermittent water rinses are preferably carried out by immersing the PWB in baths constructed of polypropylene or polyvinyl chloride (PVC) and kept agitated by a recirculation pump or pumped in air.
After the microetch step and a subsequent water rinse, the PWB may now either proceed to the photoimaging process and later be electroplated or be directly panel electroplated. It may be preferred to further clean the PWB with a citric acid anti-tarnish solution or any other acid cleaner solution or both after the above microetch step.
The thus treated printed wiring board is then ready for electroplating operation which includes immersing the PWB in a suitable electroplating bath for applying a copper coating on the hole walls of the nonconducting layer.
The present invention contemplates the use of any and all electroplating operations conventionally employed in applying a metal layer to the through hole walls of a PWB. Therefore, this claimed invention should not be limited to any particular electroplating bath parameters.
A typical copper electroplating bath is comprised of the following components in the following proportions:
| General | Preferred | ||||
| Component | Proportions | Proportions | |||
| Copper (as metal) | 2-3 | oz/gal | 2.25-2.75 | oz/gal | |
| Copper Sulfate | 5-10 | oz/gal | 6-9 | oz/gal | |
| 98% Concentrated | 23-32 | oz/gal | 27-30 | oz/gal | |
| H2SO4 (by weight) | 20-100 | mg/l | 40-60 | mg/l | |
| Chloride Ion | |||||
The electroplating bath is normally agitated and preferably maintained at a temperature of between about 20°C and 25°C C. The electroplating bath is provided with anodes, generally constructed of copper, and the printed wiring board to be plated is connected as a cathode to the electroplating circuit. For example, a current of about 30 amps per square foot is impressed across the electroplating circuit for a period of between about 40 and 60 minutes in order to effect copper plating on the hole walls of the dielectric layer positioned between the two plates of copper up to a thickness of about 1 mil±0.2 mil. This copper plating of the hole wall provides a current path between the copper layers of the printed wiring board. Other suitable electroplating conditions may be employed, if desired. Other electroplating bath compositions containing other copper salts or other metal salts such as salts of nickel, gold, palladium, silver, and the like may be employed, if desired.
The printed wiring board is removed from the copper electroplating bath and then washed and dried to provide a board which is further processed. For example, the PWB may be subjected to a tin-lead electroplating operation.
The following examples are presented to define the invention more fully without any intention of being limited thereby. All parts and percentages are by weight and all temperatures are degrees Celsius unless explicitly stated otherwise.
Six double-sided control laminated printed wiring boards and eight double-sided test printed wiring boards were treated by the process of this invention. The boards were comprised of two 35 micron thick copper plates secured by pressure fusing to the opposite sides of an epoxy resin/glass fiber layer. These double-sided printed wiring boards were about 15.24 centimeters wide by 22.86 centimeters in length. There were about 500 to 1,000 holes each about 1.0 millimeters in diameter drilled through the copper plates and epoxy resin/glass fiber layer.
A double-sided printed wiring board described above was prepared for copper electroplating their through holes by first mechanically scrubbing the surfaces of the board. The board was then immersed in the following sequence of aqueous baths for the indicated times:
1. Cleaner (5 mins.).
2. Rinse with tap water (2 mins.).
3. Conditioner (4 mins.).
4. Rinse with tap water (2 mins.).
5. Carbon black preplating dispersion (4 mins.). (Then dry at 93°C C. for 20 mins.)
6. Conditioner (4 mins.).
7. Rinse with tap water (2 mins.).
8. Graphite preplacing dispersion (4 mins.). (Then dry at 93°C C. for 20 mins.)
9. Sodium persulfate microetch (30 secs.).
10. Rinse with tap water (20 secs.).
11. Anti-tarnish solution (20 secs.).
12. Rinse with tap water (20 secs.).
Bath 1 was an aqueous solution containing a cleaner formulation comprised of monoethanolamine, SANDOLEC CF cationic polyelectrolyte, and ethylene glycol in water to remove grease and other impurities from the hole wall surfaces of the board. The bath was heated to about 60°C C. to facilitate this cleaning. The cleaner formulation is available as "BLACKHOLE Cleaner 2" from Olin Hunter Speciality Products, Inc. of West Paterson, NJ.
Bath 3 was a room temperature aqueous alkaline bath which contains monoethanolamine and SANDOLEC CF polyelectrolyte and has a pH of about 10 to condition the hole wall surfaces of the board. The conditioner formulation is available as "BLACKHOLE Conditioner" from Olin Hunt Speciality Products, Inc.
Bath 5 was a room temperature deionized water bath containing the carbon black preplating formulation. In this bath, the proportions of each ingredient were as follows:
| 0.38% | by weight anionic surfactant (1) | |
| 0.6% | by weight KOH (2) | |
| 0.38% | by weight carbon black (3) | |
| 1.24% | by weight solids | |
The balance of the bath was deionized water. This carbon black dispersion of bath 5 was prepared by high speed mixing a concentrated form of this dispersion in a high speed mixer. The surfactant was dissolved in deionized water/KOH to give a continuous phase. Then the carbon black was added. Mixing time was 6 hours. After mixing the concentrate was diluted with sufficient deionized water to make the dispersion in the above indicated proportions.
After bath 5, the boards were placed in a hot air recirculatory oven and heated to 93°C C. for 20 mins. This drying step removed the water from the carbon black coating on the board, thereby leaving a dried deposit of carbon black all over the board and in the through holes of the board. The drying promotes adhesion between the carbon black and the nonconductive surfaces of the board.
Bath 6 was the same as bath 3.
Bath 8 was a room temperature deionized water bath containing the graphite preplating formulation. In this bath, the proportions of each ingredient were as follows:
| 0.4% | by weight anionic surfactant (1) | |
| 0.6% | by weight KOH (2) | |
| 0.6% | by weight graphite (4) | |
| 1.48% | by weight solids | |
The balance of the bath was deionized water. This graphite dispersion of bath 8 was prepared by ball milling a concentrated form of this dispersion in a glass jar with stainless steel balls so that the liquid level was above the ⅛ inch diameter stainless steel balls which occupied approximately ½ of the volume of the milling jar. The material was milled for 12 hours. After milling, the concentrate was diluted with sufficient deionized water to make the dispersion in the above-indicated proportions. After bath 8, the boards were dried as described for bath 5 above.
Bath 9 was a room temperature aqueous bath and contained 200 g of sodium persulfate per liter of deionized water and 0.5% by volume of concentrated H2SO4. Its function was to microetch the copper surfaces of the board so as to remove the deposited carbon black from the surfaces. It does not act on the resin/glass surfaces. This sodium persulfate microetch was made from "BLACKHOLE Microclean I" and is available from Olin Hunt Specialty, Products, Inc. of West Paterson, NJ.
Bath 11 was a room temperature aqueous bath and contained 50 g of citric acid per liter of deionized water and 0.5% by volume of concentrated H2SO4. Its function was to prevent the copper surfaces of the printed wiring bonds from tarnishing.
Rinse baths 2, 4, 7, 10, and 12 were employed to prevent the carryover of chemicals from one treatment bath into the next.
After treatment in bath 12, the boards were air dried and evaluated by measuring the resistance between the two copper plates. This was done by placing an electrode from a Multimeter on each surface and recording the resistance. The results are obtained in Table No. 2 below.
After treatment with this sequence of baths, the printed wiring boards were placed in a commercial electroplating bath sequence including a VERSACLEAN 400 acid cleaner bath, rinse, microetch step, rinse, acid dip, and electroplating bath. The electroplating bath was provided with agitation means and heating means with contained electrolyte chemistry comprised of the following:
| Plating Bath Composition | |||
| Component | Proportion | ||
| Copper (as metal) | 2.5 | oz./gal. | |
| Copper Sulfate | 6.2 | oz./gal. | |
| 98% Concentrated H2SO4 | 30 | oz./gal. | |
| by weight | |||
| Chloride ion | 40 | mg/l | |
The printed wiring board was connected as a cathode in the electroplating vessel having a volume of about 720 liters. Twelve copper bars were immersed in the electrolyte and connected to the cell circuits as anodes. The copper bars had a length of about 91 cm; a width of about 9 cm and a thickness of about 4 cm. Each face was about 819 square cm.
A direct current of 20 amps per square foot was impressed across the electrodes in the electroplating bath for 1 min. The bath was maintained at 25°C C. during this period, and agitation was effected by air sparging. At the end of this period, the board was disconnected from the electroplating circuit, removed from the electrolyte, washed with tap water, and dried.
An examination of the through holes of the resulting electroplated printed wiring boards was conducted and the completeness of copper coverage was noted. (See Table No. 1 below for comparison to standards.) Evaluation of the copper coverage, after 1 minute of plating, was carried out by cross-sectioning and backlight methods.
A double-sided board described above was treated exactly as in Example 1, except that it was electroplated for approximately 55 mins. in order to build up a thickness of copper of approximately 0.001 inches on the hole wall surface. The holes were examined visually comparing them to standards described below. The board was then evaluated for adhesion by subjecting it to a standard solder shock test. The graphite treated holes showed excellent uniformity of the electroplated layer and excellent adhesion to the hole walls.
Two of the double-sided boards described above were treated exactly as in Examples 1 and 2 except that steps 6, 7, and 8 were outlined. One (C-1A) of the boards was electroplated for 1 min.; the second one (C-1B) for approximately 55 mins. This process is referred to as single-pass carbon black. The board C-1B was evaluated for adhesion by subjecting it to a standard solder shock test. The results are shown in Table 3.
Two double-sided boards described above were treated exactly as in Examples 1 and 2 except that step 8 (the graphite dispersion) was replaced by repeating step 5. One of the boards (C-2A) was electroplated for 1 minute and the other board (C-2B) was electroplated for approximately 55 mins. This process is referred to as double-pass carbon black. The board C-2B was evaluated for adhesion by subjecting it to a standard solder shock test. The results of that test are shown in Table 3.
Two double-sided boards described above were treated exactly as in Examples 1 and 2 except that steps 5, 6, and 7 were omitted. One of the boards (C-3A) was electroplated for 1 min. and the other (C-3B) was electroplated for approximately 55 mins. This process is referred to as single-pass graphite. This board (C-3B) was not evaluated for adhesion since significant voids were observed even after 55 mins. of plating.
A double-sided board described above was treated exactly as in Example 1 except that step 8 was replaced in its entirety by an aqueous dispersion comprised of:
| 0.4% | by weight anionic surfactant (1) | |
| 0.6% | by weight KOH (2) | |
| 0.4% | by weight graphite (5) | |
| 1.28% | by weight solids | |
The balance of the bath was deionized water. The graphite dispersion was prepared by grinding a concentrated form of this dispersion in a laboratory attritor (Model 0-1 made by Union Process of Akron, OH) so that the liquid level was just above the ⅛ inch diameter stainless steel balls which occupied approximately one half of the volume of the chamber. The material was ground for 12 hours at 70% full power. After grinding, the concentrate was diluted with sufficient deionized water to make the dispersions in the above indicated proportions.
A double-sided board described was treated exactly as in Example 2 except that Nippon AUP 0.7 micron graphite dispersion, prepared as described in Example 3 above, replaced the Showa Denko graphite dispersion in step 8.
A double-sided board described above was treated exactly as in Example 3 except that Asbury Graphite Micro-850 supplied by Asbury Graphite Mills, Asbury, NJ, replaced the Nippon AUP (0.7 micron) graphite in the dispersion described in step 8.
A double-sided board described above was treated exactly as in Example 4 except that Asbury Graphite Micro-850 replaced Nippon AUP (0.7 micron) graphite in the dispersion described in step 8.
| TABLE 1 | |||
| COOPER COVERAGE OF THROUGH HOLE AFTER | |||
| ELECTROPLATING FOR 1 MIN. AT 20 AMPS/SQ. FT | |||
| Process or | Coverage | ||
| Board | Graphite Used | After 1 Min. | |
| Example 1 | Showa Denka | 100% | |
| Comparative Example 1A | Single-pass | Less than 10% | |
| carbon black | |||
| Comparative Example 2A | Double-pass | Less than 50% | |
| carbon black | |||
| Comparative Example 3A | Single-pass | Less than 50% | |
| graphite | |||
| Example 3 | Nippon AUP | 100% | |
| 0.7 micron | |||
| Example 5 | Asbury Micro- | 100% | |
| 850 | |||
| TABLE 1 | |||
| COOPER COVERAGE OF THROUGH HOLE AFTER | |||
| ELECTROPLATING FOR 1 MIN. AT 20 AMPS/SQ. FT | |||
| Process or | Coverage | ||
| Board | Graphite Used | After 1 Min. | |
| Example 1 | Showa Denka | 100% | |
| Comparative Example 1A | Single-pass | Less than 10% | |
| carbon black | |||
| Comparative Example 2A | Double-pass | Less than 50% | |
| carbon black | |||
| Comparative Example 3A | Single-pass | Less than 50% | |
| graphite | |||
| Example 3 | Nippon AUP | 100% | |
| 0.7 micron | |||
| Example 5 | Asbury Micro- | 100% | |
| 850 | |||
| TABLE 3 | |||
| THROUGH HOLE COPPER COVERAGE & ADHESION | |||
| (SOLDER SHOCK) FOR FULLY-ELECTROPLATED (55 | |||
| MIN. AT 20 AMPS/SQ. FT.) BOARDS BOTH MEASURE- | |||
| MENTS ARE RATED AS COMPARABLE TO THE | |||
| STANDARD 2B. | |||
| Process or | |||
| Graphite | |||
| Board | Used | Coverage | Adhesion |
| Example 2 | Showa | Comparable | Comparable |
| Denko | |||
| Comp. Example 1B | Single-pass | Comparable | Comparable |
| carbon black | |||
| Comp. Example 2B | Double-pass | Acceptable | Acceptable |
| carbon black | |||
| Comp. Example 3B | Single-pass | Some voids | Not done |
| graphite | |||
| Example 4 | Nippon AUP | Comparable | Comparable |
| 0.7 micron | |||
| Example 6 | Asbury 850 | Comparable | Comparable |
Coverage results mean that the cross-sectioned boards were evaluated as to voids and uniformity of thickness. The Examples of present invention (E-2, E-4, and E-6) were all comparable to standard double-pass carbon black process. The adhesion results also show that they were comparable to standard double-pass carbon black process.
Accordingly, these results together show that boards tested according to Examples 1, 3, and 5 exhibit faster plating characteristics than all of Comparison process, while retaining the excellent coverage and adhesion characteristics of those processes.
While the invention has been described above with reference to specific embodiments thereof, it is apparent that many changes, modifications, and variations can be made without departing from the inventive concept disclosed here. Accordingly, it is intended to embrace all such changes, modifications, and variations that fall within the spirit and broad scope of the appended claims. All patent applications, patents, and other publications cited herein are incorporated by reference in their entirety.
Randolph, Catherine M., Nelsen, Barry F.
| Patent | Priority | Assignee | Title |
| 7694416, | Dec 08 2006 | Nitto Denko Corporation | Producing method of wired circuit board |
| Patent | Priority | Assignee | Title |
| 1037469, | |||
| 1352331, | |||
| 2243429, | |||
| 3099608, | |||
| 3163588, | |||
| 3715265, | |||
| 4035265, | Apr 18 1969 | The Research Association of British, Paint, Colour & Varnish | Paint compositions |
| 409096, | |||
| 4090984, | Feb 28 1977 | Owens-Corning Fiberglas Technology Inc | Semi-conductive coating for glass fibers |
| 4239794, | Oct 18 1976 | LCD ACQUISITION CORPORATION | Process of dispersing electro-conductive carbon black and web product made thereby |
| 4276278, | Jan 29 1979 | AMOCO CORPORATION, A CORP OF INDIANA | Spin size and thermosetting aid for pitch fibers |
| 4581301, | Apr 10 1984 | KAPLAN, NORMAN A | Additive adhesive based process for the manufacture of printed circuit boards |
| 4619714, | Aug 06 1984 | REGENTS OF THE UNIVERSITY OF CALIFORNIA THE A CORP OF CA | Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes |
| 4619741, | Apr 11 1985 | MACDERMID ACUMEN, INC | Process for preparing a non-conductive substrate for electroplating |
| 4622107, | May 05 1986 | MACDERMID ACUMEN, INC | Process for preparing the through hole walls of a printed wiring board for electroplating |
| 4622108, | May 05 1986 | MACDERMID ACUMEN, INC | Process for preparing the through hole walls of a printed wiring board for electroplating |
| 4631117, | May 06 1985 | MACDERMID ACUMEN, INC | Electroless plating process |
| 4684560, | Apr 11 1985 | MACDERMID ACUMEN, INC | Printed wiring board having carbon black-coated through holes |
| 4718993, | May 29 1987 | MACDERMID ACUMEN, INC | Process for preparing the through hole walls of a printed wiring board for electroplating |
| 4724005, | Apr 11 1985 | MACDERMID ACUMEN, INC | Liquid carbon black dispersion |
| 4874477, | Apr 21 1989 | MACDERMID ACUMEN, INC | Process for preparing the through hole walls of a printed wiring board for electroplating |
| 4897164, | Apr 24 1989 | MACDERMID ACUMEN, INC | Process for preparing the through hole walls of a printed wiring board for electroplating |
| 4964959, | Apr 12 1990 | MACDERMID ACUMEN, INC | Process for preparing a nonconductive substrate for electroplating |
| 4994153, | Jun 28 1990 | MACDERMID ACUMEN, INC | Process for preparing nonconductive substrates |
| 5015339, | Mar 26 1990 | MACDERMID ACUMEN, INC | Process for preparing nonconductive substrates |
| 5155798, | Feb 21 1989 | GLENRO, INC | Quick-response quartz tube infra-red heater |
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