Carrier-attached copper foil

Abstract

The present invention provides a carrier-attached copper foil, wherein an ultrathin copper foil is not peeled from the carrier prior to the lamination to an insulating substrate, but can be peeled from the carrier after the lamination to the insulating substrate. A carrier-attached copper foil comprising a copper foil carrier, an intermediate layer laminated on the copper foil carrier, and an ultrathin copper layer laminated on the intermediate layer, wherein the intermediate foil is configured with a Ni layer in contact with an interface of the copper foil carrier and a Cr layer in contact with an interface of the ultrathin copper layer, said Ni layer containing 1,000-40,000 μg/dm.sup.2 of Ni and said Cr layer containing 10-100 μg/dm.sup.2 of Cr is provided.

Claims

1. A carrier-attached copper foil comprising a copper foil carrier, an intermediate layer laminated on the copper foil carrier, and an ultrathin copper layer laminated on the intermediate layer, wherein the intermediate layer is configured with a Ni layer in contact with an interface of the copper foil carrier and a Cr-containing layer in contact with an interface of the ultrathin copper layer, said Ni layer containing 1,000-40,000 μg/dm.sup.2 of Ni and said Cr-containing layer containing 10-100 μg/dm.sup.2 of Cr.

2. The carrier-attached copper foil according to claim 1, wherein the deposition amount of Ni is 1,000-10,000 μg/dm.sup.2 and the deposition amount of Cr is 10-50 μg/dm.sup.2.

3. The carrier-attached copper foil according to claim 1, wherein the mass ratio of Cr to Ni is within the range 0.0005:1 to 0.010:1.

4. The carrier-attached copper foil according to claim 1, wherein the Cr of the Cr-containing layer has been deposited by electrolytic chromating.

5. The carrier-attached copper foil according to claim 1, wherein said Cr-containing layer is formed by electrolytic chromating, wet plating or dry plating.

6. The carrier-attached copper foil according to claim 1, wherein a roughened layer is formed on a surface of the ultrathin copper layer, wherein the surface is opposite to the surface which contacts the Cr-containing layer.

7. The carrier-attached copper foil according to claim 6, wherein said roughened layer is a layer of a single metal or an alloy containing one or more selected from the group consisting of copper, nickel, phosphorous, tungsten, arsenic, molybdenum, chromium, cobalt and zinc.

8. The carrier-attached copper foil according to claim 6, wherein at least one layer selected from an anticorrosion layer, a chromate treatment layer and a silane coupling treatment layer is formed on a surface of the roughened layer.

9. The carrier-attached copper foil according to 1, wherein at least one layer selected from an anticorrosion layer, a chromate treatment layer and a silane coupling treatment layer is formed on a surface of the ultrathin copper layer.

10. A carrier-attached copper foil comprising a copper foil carrier, an intermediate layer laminated on the copper foil carrier, and an ultrathin copper layer laminated on the intermediate layer, wherein the intermediate layer is configured with a Ni layer in contact with an interface of the copper foil carrier and a chromate or Cr-plated layer in contact with an interface of the ultrathin copper layer, said Ni layer containing 1,000-40,000 μg/dm.sup.2 of Ni and said chromate or Cr-plated layer containing 10-100 μg/dm.sup.2 of Cr.

11. The carrier-attached copper foil according to claim 10, wherein the deposition amount of Ni is 1,000-10,000 μg/dm.sup.2 and the deposition amount of Cr is 10-50 μg/dm.sup.2.

12. The carrier-attached copper foil according to claim 10, wherein the mass ratio of Cr to Ni is within the range 0.0005:1 to 0.010:1.

13. The carrier-attached copper foil according to claim 10, wherein the Cr has been deposited by electrolytic chromating.

14. The carrier-attached copper foil according to claim 10, wherein a roughened layer is formed on a surface of the ultrathin copper layer, wherein the surface is opposite to the surface which contacts the Cr-containing layer.

15. The carrier-attached copper foil according to claim 14, wherein said roughened layer is a layer of a single metal or an alloy containing one or more selected from the group consisting of copper, nickel, phosphorous, tungsten, arsenic, molybdenum, chromium, cobalt and zinc.

16. The carrier-attached copper foil according to claim 14, wherein at least one layer selected from an anticorrosion layer, a chromate treatment layer and a silane coupling treatment layer is formed on a surface of the roughened layer.

17. The carrier-attached copper foil according to 10, wherein at least one layer selected from an anticorrosion layer, a chromate treatment layer and a silane coupling treatment layer is formed on a surface of the ultrathin copper layer.

18. A printed wiring board manufactured from the carrier-attached copper foil according to claim 1.

19. A printed wiring board manufactured from the carrier-attached copper foil according to claim 10.

20. A copper clad laminate manufactured from the carrier-attached copper foil according to claim 1.

21. A copper clad laminate manufactured from the carrier-attached copper foil according to claim 10.

22. An electronic device manufactured from the carrier-attached copper foil according to claim 1.

23. An electronic device manufactured from the carrier-attached copper foil according to claim 10.

24. A method of producing a carrier-attached copper foil according to claim 1 comprising: a step of providing a Ni layer on a copper foil carrier; a step of providing a Cr-containing layer on the Ni-layer; a step of providing an ultrathin copper layer on the Cr-containing layer; wherein said Ni layer contains 1,000-40,000 μg/dm.sup.2 of Ni and said Cr-containing layer contains 10-100 μg/dm.sup.2 of Cr.

25. A method of producing a carrier-attached copper foil according to claim 24, wherein the Cr-containing layer is provided by wet plating or dry plating using Cr and Zn.

26. A method of producing a carrier-attached copper foil according to claim 25, wherein the Cr-containing layer is provided by wet plating using a solution containing Cr and Zn.

27. A method of producing a carrier-attached copper foil according to claim 26, wherein the Cr-containing layer is provided by electrolytic chromating using a solution containing Cr and Zn.

Description

EXAMPLES

(1) In the following, the present invention will be explained in details by examples, but it should be understood that the present invention is not restricted to these examples.

(2) 1. Production of a Carrier-Attached Copper Foil

(3) No. 1

(4) As a copper foil carrier, a long length of an electrolytic copper foil having a thickness of 35 μm (JTC manufactured by JX Nippon Mining & Metals Corporation) was prepared. On the shiny side of this copper foil carrier, an electroplating of Ni layer was performed under the following conditions, using a roll-to-roll continuous plating line, and thus a Ni layer having a deposition amount of 4,000 μg/dm.sup.2 was formed.

(5) Ni Layer: Nickel sulfate: 250-300 g/L Nickel chloride: 35-45 g/L Nickel acetate: 10-20 g/L Trisodium citrate: 15-30 g/L Brightener: Saccharine, butynediol or others Dodecyl sodium sulfate: 30-100 ppm pH: 4-6 Bath temperature: 50-70° C. Current density: 3-15 A/dm.sup.2

(6) After rinsing with water and pickling, a Cr layer was subsequently deposited by electrolytic chromating on the Ni layer in a deposition amount of 11 μg/dm.sup.2 using a roll-to-roll continuous plating line under the following conditions.

(7) Electrolytic Chromating Treatment Composition of solution: potassium dichromate: 1-10 g/L and Zinc 0-5 g/L pH: 3-4 Solution temperature: 50-60° C. Current density: 0.1-2.6 A/dm.sup.2 Quantity of coulomb: 0.5-30 As/dm.sup.2

(8) Subsequently, an ultrathin copper layer having a thickness of 5-10 μm was formed by electroplating on the Cr layer using the continuous roll-to-roll plating line under the following conditions.

(9) Ultrathin Copper Layer Copper concentration: 30-120 g/L H.sub.2SO concentration: 20-120 g/L Temperature of electrolytic solution: 20-80° C. Current density: 10-100 A/dm.sup.2
Nos. 2-23

(10) The test No. 1 was modified by adjusting the line speed to vary Ni and Cr deposition amount as shown in Table 1 to produce the various carrier-attached copper foils of Nos. 2-23. The examples of the zero deposition of Ni or Cr are the cases where Ni plating or electrolytic chromating was not performed.

(11) Also, with respect to the examples of Nos. 1, 7, 14 and 18, the surface of the ultrathin copper layer was subjected to roughening treatment, anti-corrosion treatment, chromating treatment and silane coupling treatment in this sequence.

(12) Roughening Treatment Cu: 10-20 g/L Co: 1-10 g/L Ni: 1-10 g/L pH: 1-4 Solution temperature: 40-50° C. Current density Dk: 20-30 A/dm.sup.2 Time: 1-5 seconds Cu deposition: 15-40 mg/cm.sup.2 Co deposition: 100-3,000 μg/dm.sup.2 Ni deposition: 100-1,000 m/dm.sup.2

(13) Anti-Corrosion Treatment Zn: more than 0 up to 20 g/L Ni: more than 0 up to 5 g/L pH: 2.5-4.5 Solution temperature: 30-50° C. Current density Dk: more than 0 up to 1.7 A/dm.sup.2 Time: 1 sec. Zn deposition: 5-250 μg/dm.sup.2 Ni deposition: 5-300 μg/dm.sup.2

(14) Chromating Treatment K.sub.2Cr.sub.2O.sub.7 (Na.sub.2Cr.sub.2O.sub.7 or CrO.sub.3): 2-10 g/L NaOH or KOH: 10-50 g/L ZnO or ZnSO.sub.4. 7H.sub.2O: 0.05-10 g/L pH: 7-13 Bath temperature: 20-80° C. Current density: 0.05-5 A/dm.sup.2 Time: 5-30 seconds. Cr deposition: 10-150 μg/dm.sup.2

(15) Silane Coupling Treatment Aqueous solution of vinyl triethoxysilane (Concentration of vinyl triethoxysilane: 0.1-1.4 wt %) pH: 4-5 Bath temperature: 25-60° C. Immersion time: 5-30 seconds.

(16) Also, with respect to the examples of Nos. 4, 5, 19, 20 and 21, the following roughening treatments 1 and 2, anticorrosion treatment, chromating treatment, and silane coupling treatment were carried out in this order on the surface of the ultrathin copper foil.

(17) Roughening Treatment 1

(18) (Composition of Solution 1)

(19) Cu: 10-30 g/L H.sub.2SO.sub.4: 10-150 g/L W: 0-50 mg/L Dodecyl sodium sulfate: 0-50 mg/L As: 0-200 mg/L
(Electroplating Condition 1) Temperature: 30-70° C. Current density: 25-110 A/dm.sup.2 Roughening coulomb: 50-500 As/dm.sup.2 Plating time: 0.5-20 seconds

(20) Roughening Treatment 2

(21) (Composition of Solution 2)

(22) Cu: 20-80 g/L H.sub.2SO.sub.4: 50-200 g/L
(Electroplating Condition 2) Temperature: 30-70° C. Current density: 5-50 A/dm.sup.2 Roughening coulomb: 50-300 As/dm.sup.2 Plating time: 1-60 seconds

(23) Anticorrosion Treatment

(24) (Composition of Solution)

(25) NaOH: 40-200 g/L NaCN: 70-250 g/L CuCN: 50-200 g/L Zn(CN).sub.2: 2-100 g/L As.sub.2O.sub.3: 0.01-1 g/L
(Solution Temperature) 40-90° C.
(Current Conditions) Current density: 1-50 A/dm.sup.2 Plating time: 1-20 seconds

(26) Chromating Treatment: K.sub.2Cr.sub.2O.sub.7 (Na.sub.2Cr.sub.2O.sub.7 or CrO.sub.3): 2-10 g/L NaOH or KOH: 10-50 g/L ZnOH or ZnSO.sub.4.7H.sub.2O: 0.05-10 g/L pH: 7-13 Bath temperature: 20-80° C. Current density: 0.05-5 A/dm.sup.2 Time: 5-30 seconds.

(27) Silane Coupling Treatment

(28) Aqueous solution of 0.1 vol %-0.3 vol % of 3-glycidoxypropyltrimethoxysilane was spray-coated and then dried and heated at 100-200° C. for 0.1-10 seconds in the air.

(29) Also, with respect to Nos. 2, 6, 8, 22 and 23, the following roughening treatments 1 and 2, anticorrosion treatment, chromating treatment, and silane coupling treatment were carried out in this sequence.

(30) Roughening Treatment 1 Composition of Solution: Cu: 10-20 g/L, sulfuric acid: 50-100 g/L Solution temperature: 25-50° C. Current density: 1-58 A/dm.sup.2 Coulomb quantity: 4-81 As/dm.sup.2

(31) Roughening Treatment 2 Composition of Solution: Cu: 10-20 g/L, Ni: 5-15 g/L, Co: 5-15 g/L pH: 2-3 Solution temperature: 30-50° C. Current density: 24-50 A/dm.sup.2 Coulomb quantity: 34-48 As/dm.sup.2

(32) Anti-Corrosion Treatment Composition of Solution: Ni 5-20 g/L, Co: 1-8 g/L pH: 2-3 Solution temperature: 40-60° C. Current density: 5-20 A/dm.sup.2 Coulomb quantity: 10-20 As/dm.sup.2

(33) Chromating Treatment Composition of Solution: potassium dichromate 1-10 g/L, zinc 0-5 g/L pH: 3-4 Bath temperature: 50-60° C. Current density: 0-2 A/dm.sup.2 (electroless chromating was applicable due to immersion chromating) Coulomb quantity: 0-2 As/dm.sup.2 (electroless chromating was applicable due to immersion chromating)

(34) Silane Coupling Treatment Coating with aqueous solution of diaminosilane (concentration of diaminosilane: 0.1-0.5 wt %)
2. Property Evaluation of the Carrier-Attached Copper Foil

(35) With respect to the carrier-attached copper foil produced according to the above conditions, property evaluation was performed in the following manners. The results are shown in Table 1. Incidentally, with respect to Nos. 1-8, 14 and 18-23, property evaluation was performed for both cases where the surface treatment was not carried out on the surface of the ultrathin copper layer and where the surface treatment was carried out. Table 1 shows the results of the case where the surface treatment was not carried out on the surface of the ultrathin copper layer. The results of property evaluation where the surface treatment was carried out on the surface of the ultrathin copper layer were similar to those where the surface treatment was not carried out on the surface of the ultrathin copper layer.

(36) Pinholes

(37) The number of the pinholes was visually counted using as a light source a backlight for photography of consumer use. The evaluation was based on the following criteria. x: Number of pinholes exceeds 10,000/dm.sup.2 Δ: There are some locations where the number of pinholes exceeds 10,000/dm.sup.2 ∘: Number of pinholes is 100-10,000/dm.sup.2 ⊚: Number of pinholes is less than 100/dm.sup.2
Peel Strength (After BT Press)

(38) The ultrathin copper layer side of the carrier-attached copper foil was laminated to a BT substrate and pressed at 195° C. for 2 hours and the carrier foil was peeled off to measure the peel strength.

(39) TABLE-US-00001 TABLE 1 Ni deposition Cr deposition Cr/Ni Peel strength No. Category (μg/dm2) (μg/dm2) *1000 Pinholes (after BT press) 1 Inventive 4,000 11 2.75 ○ Non-unifrom peeling Example (partial adhesion) 2 Inventive 9,000 11 1.22 ○ Non-unifrom peeling Example (partial adhesion) 3 Inventive 4,000 25 6.25 ⊚ ○ Example (peelable) 4 Inventive 9,000 25 2.78 ⊚ ○ Example 5 Inventive 4,000 35 8.75 ⊚ ○ Example 6 Inventive 9,000 35 3.89 ⊚ ○ Example 7 Inventive 40,000 25 0.63 Δ ○ Example 8 Inventive 40,000 35 0.88 Δ ○ Example 9 Comparative 0 25 — — Not peelable (close adhesion) Example 10 Comparative 4,000 0 0.00 ⊚ Not peelable Example (close adhesion) 11 Comparative 9,000 0 0.00 ⊚ Not peelable Example (close adhesion) 12 Comparative 40,000 0 0.00 X Peeled during in plating line Example due to insufficient adhesion 13 Comparative 90,000 0 0.00 See through Peeled during in plating line Example (many PH) due to insufficient adhesion 14 Inventive 40,000 11 0.28 Δ Non-unifrom peeling Example (partial adhesion) 15 Comparative 90,000 11 0.12 X Peeled during in plating line Example due to insufficient adhesion 16 Comparative 90,000 25 0.28 X Peeled during in plating line Example due to insufficient adhesion 17 Comparative 90,000 35 0.39 X Peeled during in plating line Example due to insufficient adhesion 18 Inventive 1,000 11 11.00 ○ Non-unifrom peeling Example (partial adhesion) 19 Inventive 2,000 12 6.00 ⊚ ○ (peelable) Example 20 Inventive 1,500 10 6.67 ⊚ ○ (peelable) Example 21 Inventive 35,000 90 2.57 Δ ○ (peelable) Example 22 Inventive 9,000 60 6.67 Δ ○ (peelable) Example 23 Inventive 15,000 50 3.33 ○ ○ (peelable) Example