SURFACE TREATMENT METHOD OF COPPER FOR THE ASSEMBLY OF POLYMER AND COPPER

Abstract

A method to treat the copper surface to manufacture the metallic assembly with the polymer and copper to have excellent bonding strength is disclosed. The present method is for treating the surface of copper for the bonded coupling of the mixture of polymer and copper by providing a method to treat the surface of copper, with

(a) an etching step with electric etching of the surface of copper,
(b) the first anodizing stage to anodize the surface of copper, and
(c) the second anodizing stage to anodize the above is firstly anodized, after an ultrasonic treatment of the secondly anodized copper, the copper is oxidized again.

Claims

1. A method to treat the copper surface for the bonded coupling of the mixture of the polymer and copper, comprising: (a) an etching step with electric etching of the surface of copper; and (b) the first anodizing stage to anodize the surface of copper; (c) the second anodizing stage to anodize the above firstly anodized; the stage (b), including a process to have it processed for 1 to 15 minutes with the current density of 0.01˜5 A/dm.sup.2 while using a pulse rectifier at the temperature of 30 to 90° C. in a mixed solvent of 0.01˜0.05 wt. % of NaNO.sub.2, 0.1˜1 wt. % of NH.sub.4F as an adjuvant, and 0.01˜0.1 wt. % C.sub.2H.sub.4(OH).sub.2 as an additive; and in the (c) stage, the second anodizing treatment proceeds with a mixed solvent of 0.1˜2 wt. % of C.sub.2K.sub.2O.sub.4, 0.1˜0.5 wt. % of Na.sub.2O.sub.3Si as an adjuvant, 0.01˜0.1 wt. % of C.sub.3H.sub.8O.sub.3 as an adjuvant, and 0.001˜0.01 wt. % of C.sub.20H.sub.24Na.sub.2O.sub.10S.sub.2 as an adjuvant, while using a pulse rectifier for 500 ms at the temperature of 30 to 70° C., at the current density of 0.01˜1 A/dm.sup.2, for 1 to 10 minutes.

2. The method of claim 1, wherein in stage (c), further including adding the silane coupling agent of 0.01˜1 wt. %, which is an additive to the mixed solvent.

3. The method of claim 2, in the (c) stage, with the Silane coupling additive as the additive may be one of (RO).sub.3Si—(CH.sub.2).sub.3—NH.sub.2, (RO).sub.3Si—(CH.sub.2).sub.2—Si(OC.sub.2H.sub.5).sub.3, (RO).sub.3Si—(CH.sub.2).sub.3—SH, (RO).sub.3Si-CH═CH.sub.2, (RO).sub.3Si—(CH.sub.3).sub.3—OOC(CH.sub.3)C═CH.sub.2, (RO).sub.3Si—(CH.sub.3).sub.3—O-CHCH.sub.2O and (RO).sub.3Si—(CH.sub.2).sub.15CH.sub.3.

4. The method of claim 1 with ultrasonic waves upon the secondly anodizing stage (c).

5. The method of claim 4, with the ultrasonic treatment with a solvent of H.sub.2SO.sub.4 of 0.001˜0.01 wt. % after adding an additive, C.sub.2H.sub.4(OH).sub.2 of 0.001˜0.01 wt. % for 1 to 3 minutes at 400 W, 24˜100 kHz, at the temperature of 30 to 60° C.

6. The method of claim 4, with the ultrasonic treatment from claim 4 with oxidization treatment.

7. The method of claim 6, with the oxidization treatment with a solvent of H.sub.2O.sub.2 of 0.1˜3 wt. % after adding an additive, Na.sub.2S.sub.2O.sub.3 of 0.001˜0.01 wt. % for 10 seconds to five minutes, at the temperature of 30 to 60° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 represents the copper substrate prior to treatment;

[0019] FIGS. 1A-E represent the changes in the oxide film from each process after treating the surface of copper.

[0020] FIG. 2 is a detailed sequential representation of the final oxide film of FIG. 1.

[0021] FIG. 3 depicts a device for the first and second anodizing and conditions thereof.

[0022] FIG. 4 is an ultrasonic device.

[0023] FIG. 5 represents the response structure of the Silane coupling agent between the polymer and copper.

[0024] FIG. 6(A) are photos of the surface of the oxide film of the copper for each process.

[0025] FIG. 6 (B) are photos of the cross-section of the copper oxide film per process.

[0026] FIG. 7 A represents a specimen produced for the T-Bend test, and it has the polymer overlaid on the copper specimen from each Example.—

[0027] FIG. 7B is a picture of the test results showing “Good” quality from the test results of the T-Bend test and how to conduct such a test.

[0028] FIG. 7C is a picture of the test results showing “No Good” quality from the test results of the T-Bend test and how to conduct such a test.

[0029] FIG. 8 A are top views of a specimen produced for a tensile strength test, and it has the polymer overlaid on the copper specimen from each embodiment.

[0030] FIG. 8B is a view of the specimen of FIG. 8A placed in an experimental apparatus for testing tensile strength, and views of the specimens after each test of temperature and humidity after adding an additive and the first and second anodizing.

[0031] FIG. 9 is the results of the tensile strength test after each test of temperature and humidity after adding an additive and the first and second anodizing.

[0032] FIG. 10A is a photo of the separated side of the specimen from embodiment 1, showing that it has been conveniently separated and has almost no polymer on the copper surface.

[0033] FIG. 10B is a picture of the separated side of the specimen from embodiment 2, showing that 20% of the polymer remains on the copper surface due to the separation.

[0034] FIG. 10C is a picture of the separated side of the specimen from embodiment 3, showing that 40% of the polymer remains on the copper surface due to the separation.

[0035] FIG. 10D is a picture of the separated side of the specimen from embodiment 4, showing that 60% of the polymer remains on the copper surface due to the separation.

[0036] FIG. 10E is a picture of the separated side of the specimen from embodiment 5, showing that 80% of the polymer remains on the copper surface due to the separation.

[0037] FIG. 11 is a comparative graph of the tensile strength test per rest time after conducting the first and second anodizing and adding the additive.

[0038] FIG. 12A is a specimen suitable for a temperature and humidity test.

[0039] FIG. 12B is a picture of a device to experiment with the temperature and humidity test.

[0040] FIG. 13 depicts sealing comparative graphs after conducting the temperature and humidity test, conducting the first and second anodizing, and adding the additive.

DETAILED DESCRIPTION

[0041] Referring the below schematics, this explains how to manufacture the bonding of the polymer and copper with this invention.

[0042] This invention is a method to treat the surface of copper in order to maximize the bonded coupling of the polymer mixture with

(a) an etching step with electric etching of the surface of copper,
(b) the first anodizing stage to anodize the surface of copper, and
(c) the second anodizing stage to anodize the above firstly anodized copper.

[0043] In stage (a), the surface of copper is processed with a mixed solution of 5 wt. % of H.sub.2SO.sub.2, 10 wt. % of HNO.sub.3, 0.1 wt. % of additional surface-active agent, etc., at 30 to 70, while using a 500 ms pulse rectifier, 1˜10 A/dm.sup.2, with electric etching for 5 to 15 minutes.

[0044] The electric etching leaves irregular etching patterns on the surface of the copper.

[0045] In stage (b), it is processed for 1 to 15 minutes with the current density of 0.01˜5 A/dm.sup.2 while using a pulse rectifier at the temperature of 30 to 90° C. in a mixed solvent of 0.01˜0.05 wt. % of NaNO.sub.2, 0.1˜1 wt. % of NH.sub.4F as an adjuvant, and 0.01˜0.1 wt. % of C.sub.2H.sub.4(OH).sub.2 as an additive.

[0046] The first anodizing is to oxidize the surface of the etched copper and generate an oxide film of the copper with fine bumps on its surface.

[0047] In the (c) stage, the second anodizing treatment proceeds with a mixed solvent of 0.1˜2 wt. % of C.sub.2K.sub.2O.sub.4, 0.1˜0.5 wt. % of Na.sub.2O.sub.3Si as an adjuvant, 0.01˜0.1 wt. % of C.sub.3H.sub.8O.sub.3 as an adjuvant, and 0.001˜0.01 wt. % of C.sub.20H.sub.24Na.sub.2O.sub.10S.sub.2 as an adjuvant, while using a pulse rectifier for 500 ms at the temperature of 30 to 70° C., at the current density of 0.01˜1 A/dm.sup.2, for 1 to 10 minutes.

[0048] In the (c) stage, the electrolyte to be used may be one of C.sub.2K.sub.2O.sub.4, NaHCO.sub.3, NaOH, Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, K.sub.2SO.sub.3, Na.sub.2SO.sub.3, NaNO.sub.2, KNO.sub.2, NaNO.sub.3, NaClO.sub.4, CH.sub.3COONa, Na.sub.2B.sub.207, NaH.sub.2PO.sub.2, (NaPO.sub.3).sub.6, Na.sub.2MoO.sub.4, Na.sub.3SiO.sub.3, and Na.sub.2HPO.sub.3.

[0049] In stage (c), through the second anodizing, during the first anodizing on the copper surface, the bumps, generated from the first anodizing will formulate sharp bumps that look like fine thorns of cactus between the thin oxide film, and it will generate a thin rough complex of oxide films, maximize the contacting area, and then maximize the bonding strength between the polymer and copper.

[0050] In stage (c), 0.01˜1 wt. % of a silane coupling additive as an additive is added to the mixed solution to maximize the bonding strength between the copper and polymer after the second anodizing.

[0051] The additional bonding strength was occurred due to the overlapping of van der Waals force between the polymer and the additive remaining in the copper oxide film from the second anodizing.

[0052] In the (c) stage, the Silane coupling additive as the additive may be one of (RO).sub.3Si—(CH.sub.2).sub.3—NH.sub.2, (RO).sub.3Si—(CH.sub.2).sub.2—Si(OC.sub.2H.sub.5).sub.3, (RO).sub.3Si—(CH.sub.2).sub.3—SH, (RO).sub.3Si-CH═CH.sub.2, (RO).sub.3Si—(CH.sub.3).sub.3—OOC(CH.sub.3)C═CH.sub.2, (RO).sub.3Si—(CH.sub.3).sub.3—O—CHCH.sub.2O and (RO).sub.3Si—(CH.sub.2).sub.15CH.sub.3.

[0053] After the stage (c), upon the copper with the second anodizing treatment, the ultrasonic treatment shall proceed with a solvent of H.sub.2SO.sub.4 of 0.001˜0.01 wt. % after adding an additive, C.sub.2H.sub.4(OH).sub.2 of 0.001˜0.01 wt. %, for 1 to 3 minutes at 400 W, 24˜100 kHz, at the temperature of 30 to 60° C.

[0054] From the ultrasonic treatment, via the first and second anodizing, fine micro-cracks are formed on the bumps of the oxide films, generated on the copper surface. It will roughen the surface even further, maximize the contacting area, and then maximize the bonding strength between the polymer and copper.

[0055] Finally, the copper after the ultrasonic treatment, the oxidization treatment shall proceed with a solvent of H.sub.2O.sub.2 of 0.1˜3 wt. % after adding an additive, Na.sub.2S.sub.2O.sub.3 of 0.001˜0.01 wt. %, for 10 seconds to five minutes, at the temperature of 30 to 60° C.

[0056] With the final oxidation treatment, after the ultrasonic treatment, with the fine micro-cracks on the bumps of the oxide films of the copper surface, oxidation will occur, and fine bumps on the oxide films will occur additionally from the micro cracks. By this, the contacting area with the surface of copper shall be maximized and, hence, the bonding strength of the copper and polymer shall be maximized as well.

[0057] FIG. 1 represents the changes in the oxide film from each process after treating the surface of copper.

[0058] FIG. 2 represents the specific shapes of the oxide film, generated from each process.

[0059] After this, specific examples and figures will be explained.

Embodiment 1

[0060] In stage (a), the surface of copper is processed with a mixed solution of 5% wt. H.sub.2SO.sub.2, 10 wt. % HNO.sub.3, 0.1 wt. % additional additive (surfactant), etc., at 30 to 70° C., while using a 500 ms pulse rectifier, 1˜10 A/dm.sup.2 of current density, with electric etching for 5 to 15 minutes.

[0061] In stage (b), a specimen was made only with the first anodizing by leaving it for 1 to 15 minutes with the current density of 0.01˜5 A/dm.sup.2 while using a pulse rectifier at the temperature of 30 to 90° C. in a mixed solvent of 0.01˜0.05 wt. % of NaNO.sub.2, 0.1˜1 wt. % of NH.sub.4F as an adjuvant, and 0.01˜0.1 wt. % of C.sub.2H.sub.4(OH).sub.2 as an additive.

Embodiment 2

[0062] After the etching treatment with etching from the electricity of stage (a),

[0063] after the first anodizing of the stage (b),

[0064] in the (c) stage, the second anodizing treatment proceeds with a mixed solvent of 0.1˜2 wt. % of C.sub.2K.sub.2O.sub.4, 0.1˜0.5 wt. % of Na.sub.2O.sub.3Si as an adjuvant, 0.01˜0.1% of C.sub.3H.sub.8O.sub.3 as an adjuvant, and 0.001˜0.01 wt. % of C.sub.20H.sub.24Na.sub.2O.sub.10S.sub.2 as an adjuvant, while using a pulse rectifier for 500 ms at the temperature of 30 to 70° C., at the current density of 0.01˜1 A/dm.sup.2, for 1 to 10 minutes, on the copper after the first anodizing treatment to produce a specimen.

Embodiment 3

[0065] After the etching treatment with etching from the electricity of stage (a),

[0066] after the first anodizing of stage (b),

[0067] a specimen was made by adding a silane coupling additive with an 0.01˜1 wt. % additive to the mixed solvent for the second anodizing in stage (c).

Embodiment 4

[0068] After the etching treatment with etching from the electricity of stage (a),

[0069] after the first anodizing of stage (b),

[0070] after adding silane coupling additive with an 0.01˜1 wt. % additive to the mixed solvent for the second anodizing during the second anodizing in the stage (c),

[0071] a specimen was made with the ultrasonic treatment with a solvent of H.sub.2SO.sub.4 of 0.001˜0.01 wt. % after adding an additive, C.sub.2H.sub.4(OH).sub.2 of 0.001˜0.01 wt. %, for 1 to 3 minutes at 400 W, 24˜100 kHz, at the temperature of 30 to 60° C., upon the copper after the second anodizing.

Embodiment 5

[0072] After the etching treatment with etching from the electricity of stage (a),

[0073] after the first anodizing of stage (b),

[0074] after adding silane coupling additive with an 0.01 to 1% additive to the mixed solvent for the second anodizing during the second anodizing in the stage (c) 2,

[0075] after the ultrasonic treatment on the copper after the second anodizing,

[0076] a specimen was made by the oxidization treatment with a solvent of H.sub.2O.sub.2 of 0.1˜3 wt. % after adding an additive, Na.sub.2S.sub.2O.sub.3 of 0.001˜0.01 wt. %, for 10 seconds to five minutes, at the temperature of 30 to 60° C., on the copper after the ultrasonic treatment.

[0077] With the specimens from embodiments 1 to 5, tests were conducted to measure the bonding strength and sealing quality by the resistance test, T-Bend test, tensile strength test, and rest time test. The followings are the results thereof.

[Test 1]

[0078] By using the specimens from embodiments 1 to 5, resistance was measured, the capability of carrying-out electricity was confirmed, and the results thereof are notated in Table 1.

TABLE-US-00001 TABLE 1 embodi- embodi- embodi- embodi- embodi- test piece ment 1 ment 2 ment 3 ment 4 ment 5 resistance value good good good good good (pass current)

[Test 2]

[0079] By using the specimens from embodiment 1 to 5, to measure the bonding strength, after 1,000 hours of the temperature and humidity test, the T-bend test was conducted and the results thereof are marked in Table 2.

TABLE-US-00002 TABLE 2 embodi- embodi- embodi- embodi- embodi- test piece ment 1 ment 2 ment 3 ment 4 ment 5 T-bend test No Good Good Good Good Good

[0080] As shown in Table 2, rather than the specimen from embodiment 1 with the first anodizing, the specimens from embodiments 2 to 5 with the second anodizing show more excellent characteristics in the bonding strength.

[0081] FIG. 7a is a specimen produced for the T-Bend test, and it has the polymer overlaid on the copper specimen from each Example.

[0082] FIG. 7b is a picture of the test results showing “Good” quality from the test results of the T-Bend test and how to conduct such a test.

[0083] FIG. 7c is a picture of the test results showing “No Good” quality from the test results of the T-Bend test and how to conduct such a test.

[Test 3]

[0084] By using the specimens from embodiments 1 to 5, to measure the bonding strength, after 1,000 hours of the temperature and humidity test, the T-bend test was conducted and the results thereof are marked in Table 9.

[0085] Just as a graph in FIG. 9, rather than the specimen from embodiment 1, the specimen from embodiment 2 shows excellent tensile strength before and after the temperature and humidity test.

[0086] Also, rather than the specimen from embodiment 2, the specimen from embodiment 3 shows excellent tensile strength before and after the temperature and humidity test.

[0087] Rather than the specimen from embodiment 3, the specimen from embodiment 4 shows excellent tensile strength before and after the temperature and humidity test.

[0088] Finally, rather than the specimen from embodiment 4, the specimen from embodiment 5 shows excellent tensile strength before and after the temperature and humidity test.

[0089] FIG. 8A is a specimen produced for a tensile strength test, and it has the polymer overlaid on the copper specimen from each embodiment.

[0090] FIG. 8B is a picture of the experimental method of the tensile strength test.

[0091] FIG. 10 is a picture of the amount of the polymer remaining on the copper surface, separated from the specimens of embodiments 1 to 5 after conducting the experiments on the tensile strength after the temperature and humidity test.

[0092] FIG. 10A is a picture of the separated side of the specimen from embodiment 1, showing that it has been conveniently separated and has almost no polymer on the copper surface.

[0093] FIG. 10B is a picture of the separated side of the specimen from embodiment 2, showing that 20% of the polymer remains on the copper surface due to the separation.

[0094] FIG. 10C is a picture of the separated side of the specimen from embodiment 3, showing that 40% of the polymer remains on the copper surface due to the separation.

[0095] FIG. 10D is a picture of the separated side of the specimen from embodiment 4, showing that 60% of the polymer remains on the copper surface due to the separation.

[0096] FIG. 10E is a picture of the separated side of the specimen from embodiment 5, showing that 80% of the polymer remains on the copper surface due to the separation.

[0097] The graph in FIG. 11 is the test results of the tensile strength 1 to 12 months after overlaying the polymer on the specimens from each embodiment.

[0098] Likewise, rather than the specimen from embodiment 1, the specimen from embodiment 2 shows better quality in the decline of the tensile strength as time passes.

[0099] Also, rather than the specimen from embodiment 2, the specimen from embodiment 3 shows that tensile strength declines much more as time passes.

[0100] Rather than the specimen from embodiment 3, the specimen from embodiment 4 shows that tensile strength declines much more as time passes.

[0101] Finally, rather than the specimen from embodiment 4, the specimen from embodiment 5 shows that tensile strength declines much more as time passes. [Test 4]

[0102] By using the specimens from embodiments 1 to 5, to measure the sealing condition between the copper and polymer, the temperature and humidity test was conducted and the results thereof are shown in FIG. 13.

[0103] Just as a graph in FIG. 13, rather than the specimen from embodiment 1, the specimen from embodiment 2 shows better sealing quality.

[0104] Also, rather than the specimen from embodiment 2, the specimen from embodiment 3 shows better sealing quality.

[0105] Also, rather than the specimen from embodiment 3, the specimen from embodiment 4 shows better sealing quality.

[0106] Finally, rather than the specimen from embodiment 4, the specimen from embodiment 5 shows the best sealing quality.

[0107] FIG. 12A is a picture of a specimen for a temperature and humidity test.

[0108] FIG. 12B is a picture of a device to experiment with the temperature and humidity test.

[Feasibility to be Used in Industries]

[0109] This invention is a method to manufacture the assembly of the polymer and copper by reinforcing the bonding strength of the polymer and copper with treatments on the copper surface, enhancing the sealing quality of components, making them lighter, and saving money for those components.