Component carrier with different surface finishes and method for manufacturing the same

Abstract

A component carrier and a method for manufacturing the same are disclosed. The component carrier includes an electrically conductive layer structure and an overhanging end. A first surface finish is formed on a first surface portion of the electrically conductive layer structure. Furthermore, the component carrier further includes a second surface finish on a second surface portion of the electrically conductive layer structure connected to the first surface finish and extending under the overhanging end.

Claims

1. A component carrier, comprising: an electrically conductive layer structure with a first portion extending inside a stack of the component carrier and a second portion extending on the stack including an exposed surface; a first surface finish formed only on a first surface portion of the exposed surface of the electrically conductive layer structure and having an overhanging end; and a second surface finish formed only on a second surface portion of the exposed surface of the electrically conductive layer structure connecting to the first surface finish and extending under the overhanging end.

2. The component carrier according to claim 1, wherein the second surface finish connects to a roughened surface of the first surface finish.

3. The component carrier according to claim 1, wherein the first surface finish comprises: a first layer structure arranged above the electrically conductive layer structure; and a second layer structure arranged above the first layer structure; wherein a thickness of the first layer structure is equal to a thickness of the second surface finish.

4. The component carrier according to claim 3, wherein the first layer structure and/or the second layer structure comprise at least one from the group consisting of nickel, palladium, platinum, gold, copper.

5. The component carrier according to claim 4, wherein a chemical composition of the first layer structure and a chemical composition of the second layer structure differ from each other.

6. The component carrier according to claim 1, wherein the first surface finish comprises: a first layer structure arranged above the electrically conductive layer structure; and a second layer structure arranged above the first layer structure; wherein the second layer structure is a homogeneous layer structure arranged directly on the first layer structure, and wherein the first layer structure comprises nickel and the second layer structure comprises palladium.

7. The component carrier according to claim 1, wherein the second surface finish comprises at least one from the group consisting of organic solderability preservative component, nickel, palladium, platinum, gold, copper.

8. The component carrier according to claim 7, wherein the organic solderability preservative component is an azole.

9. The component carrier according claim 8, wherein the azole is one from the group consisting of benzotriazoles, imidazoles, benzimidazoles.

10. The component carrier according to claim 1, wherein the electrically conductive layer structure comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, and tungsten.

11. The component carrier according to claim 1, wherein the at least one electrically insulating layer structure comprises at least one of the group consisting of resin, reinforced or non-reinforced resin, epoxy resin or Bismaleimide-Triazine resin, FR-4, FR-5, cyanate ester, polyphenylene derivate, glass, prepreg material, polyimide, polyamide, liquid crystal polymer, epoxy-based Build-Up Film, polytetrafluoroethylene, a ceramic, and a metal oxide.

12. The component carrier according to claim 1, wherein the component carrier is shaped as a plate.

13. The component carrier according to claim 1, wherein the component carrier is configured as one of the group consisting of a printed circuit board, and a substrate.

14. The component carrier according to claim 1, configured as a laminate-type component carrier.

15. A method of manufacturing a component carrier, the method comprising: forming a first surface finish only on a first surface portion of an exposed surface of an electrically conductive layer structure; forming an overhanging end of the first surface finish by removing material of the first surface finish; and forming a second surface finish only on a second surface portion of the exposed surface of the electrically conductive layer structure, wherein the second surface finish is connected to the first surface finish and extends under the overhanging end; wherein the electrically conductive layer structure has a first portion extending inside a stack of the component carrier and a second portion extending on the stack including the exposed surface.

16. The method according to claim 15, wherein the removing of material of the first surface finish comprises an etching process.

17. The method according to claim 16, wherein the first surface finish comprises a first layer structure and a second layer structure and wherein the etching process selectively removes material of the first layer structure of the first surface finish.

18. The method according to claim 16, wherein the etching process comprises an application of an etching composition comprising H.sub.2O.sub.2 and H.sub.2SO.sub.4.

19. A component carrier, comprising: an electrically conductive layer structure with a first portion extending inside a stack of the component carrier and a second portion extending on the stack including an exposed surface; a first surface finish formed on a first surface portion of the exposed surface of the electrically conductive layer structure and having an overhanging end; and a second surface finish on a second surface portion of the exposed surface of the electrically conductive layer structure connecting to the first surface finish and extending under the overhanging end; wherein the first portion of the electrically conductive layer structure comprises a first part extending parallel to the exposed surface and a regularly shaped second part connecting the first part with the second portion of the electrically conductive layer structure.

20. The component carrier according to claim 19, wherein the second surface finish connects to an etched surface of the first surface finish.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a first embodiment of a component carrier according to the invention.

(2) FIGS. 2A and 2B illustrate a method for manufacturing the component carrier of FIG. 1 according to an embodiment of the invention.

(3) FIG. 3 shows a second embodiment of a component carrier according to the invention.

(4) FIGS. 4A, 4B and 4C illustrate a method for manufacturing the component carrier of FIG. 3 according to an embodiment of the invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

(5) The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.

(6) The illustrations in the drawings are schematically presented. It is noted that in different figures, similar or identical elements or features are provided with the same reference signs or with reference signs, which are different from the corresponding reference signs only within the first digit. In order to avoid unnecessary repetitions elements or features which have already been elucidated with respect to a previously described embodiment are not elucidated again at a later position of the description.

(7) Further, spatially relative terms, such as “front” and “back”, “above” and “below”, “left” and “right”, et cetera are used to describe an element's relationship to another element(s) as illustrated in the figures. Thus, the spatially relative terms may apply to orientations in use which differ from the orientation depicted in the figures. Obviously all such spatially relative terms refer to the orientation shown in the figures only for ease of description and are not necessarily limiting as an apparatus according to an embodiment of the invention can assume orientations different than those illustrated in the figures when in use.

(8) FIG. 1 shows an embodiment of a component carrier according to the invention. The component carrier 100 as shown in FIG. 1 comprises a laminated stack 108. The laminated stack 108 comprises an electrically insulating layer structure 115 with a first portion of an electrically conductive layer structure 120a, 120b extending inside the laminated stack 108 and with a second portion of the electrically conductive layer structure 150 extending on the laminated stack 108 forming an exposed structured copper surface. The electrically conductive layer structure 120a, 120b, 150 is preferably made of copper. The electrically conductive layer structure 120a, 120b inside the laminated stack 108 is connected to the electrically conductive layer structure 150 extending on the laminated stack 108 by vias 125a, 125b.

(9) The component carrier 100 further comprises a first surface finish 160 formed on a first surface portion of the electrically conductive layer structure 150. The first surface finish 160 forms an overhanging end 162. The overhanging end 162 has a roughened surface 166. The component carrier 100 further comprises a second surface finish 190 on a second surface portion of the electrically conductive layer structure 150 connecting to the first surface finish 160 and extending under the overhanging end 162. The electrically conductive layer structure 150 connects to the overhanging end 162 of the first surface finish 160.

(10) Due to the overhanging end 162 of the first surface finish 160, the interaction surface of the first surface finish 160 and the second surface finish 190 is enlarged compared to the case where a first surface finish 160 and a second surface finish 190 are positioned adjacent to each other without any overlap, i.e. a contact being established only in a sideward way. Therefore the inventive architecture with the overhanging end 162 of the first surface finish 160 under which the second surface finish 190 at least partly extents avoids delamination of the first surface finish and the second surface finish, a decomposition and/or delamination and gap formation at the interface of the two surface finishes.

(11) FIG. 2A illustrates a first step of a method according to an embodiment of the invention. A first surface finish 160 on a first surface portion of the electrically conductive layer structure 150 is formed.

(12) FIG. 2B illustrates a further step of a method according to an embodiment of the invention. An overhanging end 162 and a corresponding cavity 264 of the first surface finish 160 is formed by removing material of the first surface finish 160. An etching process allows for the removal of material of the first surface finish 160 resulting in the cavity 264 having a roughened surface 266 which cavity surface being formed by surface portions of the first surface finish 160, and the electrically conductive layer structure 150.

(13) Next, a second surface finish 190 on a second surface portion of the electrically conductive layer structure 150 is formed, which second surface finish 190 is connected to the first surface finish 160 and extending under the overhanging end 162 (see FIG. 1).

(14) The final component carrier 100 (as shown in FIG. 1) obtained by the illustrated method is a component carrier having a second surface finish 190 connecting to a roughened surface 166 resulting from the etching process of the first surface finish 160.

(15) FIG. 3 shows another embodiment of a component carrier according to the invention. The first surface finish 360 of the component carrier 300 shown in FIG. 3 further comprises a first layer structure 380 arranged above the electrically conductive layer structure 150 and a second layer structure 370 arranged above the first layer structure 380. The second surface finish 390 extends under the overhanging end 362 connecting to surface portions of the second layer structure 370, the first layer structure 380 and the electrically conductive layer structure 150.

(16) FIG. 4A illustrates a first step of a method according to an embodiment of the invention. A first layer structure 380 of a first surface finish 360 is formed on a first surface portion of the electrically conductive layer structure 150 of a method for manufacturing of component carrier 300 as shown in FIG. 3.

(17) FIG. 4B illustrates a further step of a method according to an embodiment of the invention. A second layer structure 370 is formed on the first layer structure 380. Both the first layer structure 380 and the second layer structure 370 form the first surface finish 360.

(18) FIG. 4C illustrates a further step of a method according to an embodiment of the invention. An overhanging end 362 and a corresponding cavity 464 are formed by removing material of the first surface finish 360. An etching process allows for a selective removal of material of the first layer structure 380 of the first surface finish 360 while the second layer structure 370 is basically left intact resulting in a cavity 464 with a roughened surface formed by surface portions of the second layer structure 370, the electrically conductive layer structure 150 and the first layer structure 380. The final component carrier 300 (as shown in FIG. 3) is obtained by providing a second surface finish 390 extending under the overhanging end 362 and connecting to the roughened surface resulting from the etching process of the first surface finish 360.

(19) It should be noted that the term “comprising” does not exclude other elements or steps and the use of articles “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined.

LIST OF REFERENCE SIGNS

(20) 100, 300 component carrier 108 laminated stack 115 electrically insulating layer structure 120a, 120b electrically conductive layer structure 125a, 125b electrically conductive layer structure 150 electrically conductive layer structure 160, 360 first surface finish 380 first layer structure 370 second layer structure 162, 362 overhanging end 166 roughened surface/etched surface 190, 390 second surface finish 264, 464 cavity