Connection arrangement, component carrier and method of forming a component carrier structure

Abstract

A connection arrangement for forming a component carrier structure is disclosed. The connection arrangement includes a first electrically conductive connection element and a second electrically conductive connection element. The first connection element and the second connection element are configured such that, upon connecting the first connection element with the second connection element along a connection direction, a form fit is established between the first connection element and the second connection element that limits a relative motion between the first connection element and the second connection element in a plane perpendicular to the connection direction. A component carrier and a method of forming a component carrier structure are also disclosed.

Claims

1. A connection arrangement for forming a component carrier structure, the connection arrangement comprising: a first electrically conductive connection element; and a second electrically conductive connection element; wherein the first connection element and the second connection element are configured such that, upon connecting the first connection element with the second connection element along a connection direction, a form fit is established between the first connection element and the second connection element that limits a relative motion between the first connection element and the second connection element in a plane perpendicular to the connection direction, wherein at least one of the connection elements is a pillar having a non-circular cross-section, wherein at least one of the connection elements is composed by a plurality of pillars, wherein some of the pillars are interconnected by elongated pads.

2. The connection arrangement according to claim 1, further comprising: a third connection element arranged in the connection direction between the first connection element and the second connection element for accomplishing a form fit both between the first and third connection elements and between the second and third connection elements.

3. The connection arrangement according to claim 1, wherein cooperating surfaces of the connection elements are configured for promoting centering of the connection elements upon their connection, wherein a cooperating surface of one of the first and the second connection elements has a concave shape and a cooperating surface of the other one of the first and the second connection elements has a complementary convex shape.

4. The connection arrangement according to claim 1, wherein at least one of the connection elements has a concave connection surface with a dimple which is at least partially filled by a solderable material.

5. The connection arrangement according to claim 1, wherein the first connection element and the second connection element establish an electric contact and a mechanical contact both in the connection direction and in a direction perpendicular to the connection direction.

6. The connection arrangement according to claim 5, wherein the first connection element is composed of multiple spaced bodies delimiting an accommodation volume for receiving and accommodating the second connection element.

7. The connection arrangement according to claim 1, wherein at least one of the connection elements is a copper pillar, a via, a land, a solder ball or a ball comprising a central non-solderable body coated with solderable material.

8. The connection arrangement according to claim 1, wherein one of the first and second connection elements forms a part of a component to be embedded or surface mounted in or on a stack of layer structures, and the other one of the first and second connection elements is formed in an interior of the stack or at a main surface of the stack.

9. The connection arrangement according to claim 8, wherein the other one of the first and second connection elements protrudes in the connection direction from the main surface of the stack of a component carrier structure.

10. The connection arrangement according to claim 9, wherein the component carrier structure comprises at least one of a panel, an array, a component carrier, and an arrangement of a component carrier and the component.

11. A component carrier, comprising: a stack including at least one electrically conductive layer structure and/or at least one electrically insulating layer structure; and a connection arrangement in and/or on the stack, the connection arrangement including a first connection element and a second connection element, the connection elements configured such that upon connecting the first connection element with the second connection element along a connection direction, a form fit is established between the first connection element and the second connection element that limits a relative motion between the first connection element and the second connection element in a plane perpendicular to the connection direction, wherein at least one of the connection elements is a pillar having a non-circular cross-section, wherein at least one of the connection elements is composed by a plurality of pillars, wherein some of the pillars are interconnected by elongated pads.

12. The component carrier according to claim 11, comprising at least one of the following features: at least one component being surface mounted on and/or embedded in the component carrier, wherein the at least one component is selected from a group consisting of an electronic component, an electrically non-conductive and/or electrically conductive inlay, a heat transfer unit, a light guiding element, an energy harvesting unit, an active electronic component, a passive electronic component, an electronic chip, a storage device, a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface element, a voltage converter, a cryptographic component, a transmitter and/or receiver, an electromechanical transducer, an actuator, a microelectromechanical system, a microprocessor, a capacitor, a resistor, an inductance, an accumulator, a switch, a camera, an antenna, a magnetic element, a further component carrier, and a logic chip; wherein at least one of the electrically conductive layer structures of the component carrier comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, and tungsten; wherein the electrically insulating layer structure comprises at least one of the group consisting of 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; wherein the component carrier is shaped as a plate; wherein the component carrier is configured as one of the group consisting of a printed circuit board, a substrate, and an interposer; wherein the component carrier is configured as a laminate-type component carrier.

13. A method of forming a component carrier structure, the method comprising: providing a first electrically conductive connection element and a second electrically conductive connection element; connecting the first electrically conductive connection element with the second electrically conductive connection element along a connection direction in such a way that a form fit is established between the first connection element and the second connection element that limits motion of the first connection element and the second connection element relative to each other in a plane perpendicular to the connection direction, wherein at least one of the connection elements is a pillar having a non-circular cross-section, wherein at least one of the connection elements is composed by a plurality of pillars, wherein some of the pillars are interconnected by elongated pads.

14. The method according to claim 13, wherein the first and second connection elements are connected by sound-supported soldering.

15. A connection arrangement for forming a component carrier structure, the connection arrangement comprising: a first electrically conductive connection element; and a second electrically conductive connection element; wherein the first connection element and the second connection element are configured such that, upon connecting the first connection element with the second connection element along a connection direction, a form fit is established between the first connection element and the second connection element that limits a relative motion between the first connection element and the second connection element in a plane perpendicular to the connection direction, wherein the first connection element is composed of multiple spaced bodies delimiting an accommodation volume for receiving and accommodating the second connection element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a longitudinal section of a connection arrangement according to an exemplary embodiment of the invention.

(2) FIG. 2 illustrates different cross-sectional views of first and second connection elements according to exemplary embodiments of the invention.

(3) FIG. 3 illustrates a longitudinal section of a connection arrangement according to an exemplary embodiment of the invention.

(4) FIG. 4 illustrates a longitudinal section and a cross section of a connection arrangement according to an exemplary embodiment of the invention.

(5) FIG. 5 illustrates cross-sectional views and longitudinal sections of a connection arrangement according to an exemplary embodiment of the invention.

(6) FIG. 6 illustrates longitudinal sections of a connection arrangement according to an exemplary embodiment of the invention.

(7) FIG. 7 illustrates cross-sectional views of connection elements according to exemplary embodiments of the invention.

(8) FIG. 8 illustrates a cross-sectional view of connection elements according to an exemplary embodiment of the invention.

(9) FIG. 9 illustrates cross-sectional views and longitudinal sections of connection elements according to exemplary embodiments of the invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

(10) The illustrations in the drawings are schematically presented. In different drawings, similar or identical elements are provided with the same reference signs.

(11) FIG. 1 illustrates a longitudinal section of a connection arrangement according to an exemplary embodiment of the invention. The connection arrangement is basically used to connect two connection partners, for example a component and a stack, or two PCBs. The pair of both connection partners can comprise the connection arrangement.

(12) The connection arrangement can be part of component carrier structure which comprises at least one of a panel, an array, a component carrier, and an arrangement of a component carrier and a component 5.

(13) The component carrier can comprise at least one component 5 being surface mounted on and/or embedded in the component carrier, wherein the at least one component is in particular selected from a group consisting of an electronic component, an electrically non-conductive and/or electrically conductive inlay, a heat transfer unit, a light guiding element, an energy harvesting unit, an active electronic component, a passive electronic component, an electronic chip, a storage device, a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface element, a voltage converter, a cryptographic component, a transmitter and/or receiver, an electromechanical transducer, an actuator, a hermetic device, a microelectromechanical system, a microprocessor, a capacitor, a resistor, an inductance, an accumulator, a switch, a camera, an antenna, a magnetic element, a further component carrier, and a logic chip.

(14) The component carrier can comprise a stack 6 comprising at least one electrically conductive layer structure and/or at least one electrically insulating layer structure, and the connection arrangement.

(15) At least one of the electrically conductive layer structures of the component carrier can comprise at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, titanium, and tungsten, any of the mentioned materials being optionally coated with supra-conductive material such as graphene.

(16) The electrically insulating layer structure can comprise at least one of the group consisting of resin, in particular reinforced or non-reinforced resin, for instance 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.

(17) The component carrier can be shaped as a plate. The component carrier can be configured as one of the group consisting of a printed circuit board, a substrate, and an interposer. The component carrier can be configured as a laminate-type component carrier.

(18) The connection arrangement comprises (in this embodiment three) first electrically conductive connection elements 1 and (in this embodiment three) second electrically conductive connection elements 2. The first connection elements 1 and the second connection elements 2 are configured such that, upon connecting the first connection elements 1 with the second connection elements 2 along a connection direction z, a form fit is directly established between a pair of one of the first connection elements 1 and the corresponding second connection element 2 that limits or even inhibits a relative motion between the first connection element 1 and the second connection element 2 of the pair in a plane perpendicular to the connection direction z.

(19) At least the second connection elements 2 can be formed of copper by a conventional electroplating process.

(20) In this embodiment, the second connection elements 2 each have a concave connection surface 22 with a dimple which is at least partially filled by a solderable material 4. As the solderable material 4, soft solders and alloys of copper, silver, zinc, tin, or lead with optional additives of bismuth, indium, cadmium can be used. Also brazing alloys for example of brass or nickel silver are conceivable. The solderable material 4 can be deposited by any method such as sputtering. By producing the concave connection surface 22 of the second connection elements 2 with the dimple, the same can be used for centering and contacting a matching first connection element 1 which are copper pillars in this embodiment. The use of the dimples further enables the use of a larger amount of solderable material 4 compared with connection surfaces without dimples. The larger amount of solderable material 4 in turn enables larger distances to be bridged between the first and second connection elements 1, 2 in the connection direction z. Ideally, the pillar formed by the first connection element 1 should have a complementary convex shape to enhance the centering process. The convex and concave shapes of the connection surfaces 21, 22 of the first and second connection elements 1, 2 can thus be used as a support for centering the component 5 with respect to the stack 6 before or during soldering. The dimple can be used to assist cohesion forces to center the component 5; this especially applies for a relative light component 5. When a relative heavy component 5 is used, the same can be centered under vibration support such as sound-supported soldering. The centering can take place when the solderable material 4 becomes liquid. As a result, a soldering is achieved without blowholes, and a surface in a connection region can be sealed without cracks, pores etc.

(21) The first connection elements 1 each form a part, for example a terminal, a pad or a contact, of the component 5 to be embedded or surface mounted in or on the stack 6 of layer structures, and the second connection elements 2 are formed in an interior of the stack 6.

(22) Alternatively, instead of being formed in the interior of the stack 6, the second connection elements 2 can protrude in the connection direction z from the main surface of the stack 6 of the component carrier structure, or they can be formed at or on a main surface of the stack 6. In the context of the present invention, the term “main surface” designates that surface where terminals or contacts are arranged or that surface which extends perpendicular to a direction in which the conductive and insulating layers are superposed (layered) on each other.

(23) FIG. 2 illustrates different cross-sectional views of first and second connection elements 1, 2 according to exemplary embodiments of the invention.

(24) At the left side of FIG. 2, a cross section of the second connection element 2 is shown, which has a non-circular cross-section.

(25) In the upper middle of FIG. 2, the first connection element 1 has a circular cross-section, whereas in the lower middle of FIG. 2, the first connection element 1 has a non-circular cross-section. As can be taken from the right side of FIG. 2, a contact surface between the first and second connection elements 1, 2 is enlarged with the first connection element 1 having the non-circular cross-section.

(26) The non-circular cross-sections can have an oval, elliptic or any other non-circular shape. Due to the non-circular cross-sections, the registration tolerances can be enlarged. The accuracy in a contacting process can also be increased.

(27) FIG. 3 illustrates a longitudinal section of a connection arrangement according to an exemplary embodiment of the invention. Each first connection element 1 has a first cooperating surface 11, and each second connection element 2 has a second cooperating surface 12. During connecting the first and second connection elements 1, 2, the first and second cooperating surfaces 11, 21 cooperate and engage with each other. The cooperating surfaces 11, 21 of the connection elements 1, 2 are configured for promoting centering of the connection elements 1, 2 upon their connection.

(28) The first and second cooperating surfaces 11, 21 have complementary shapes. In more detail, the cooperating surface 11, 21 of one of the first and the second connection elements 1, 2 has a concave shape and the cooperating surface 11, 21 of the other one of the first and the second connection elements 1, 2 has a complementary convex shape in the cross section perpendicular to the connection direction z.

(29) The second connection elements 2 can be formed of copper by a conventional electroplating process. Each second connection element 2 has a shape of a pillar or of an elevated land which protrudes from a solder mask 8, which is provided as an uppermost layer on the stack 6. At the top of each pillar or elevated land, the cooperating surfaces 11, 21 are provided.

(30) For example, by the complementary (convex or concave) shapes of the cooperating surfaces 21, 22 of the first and second connection elements 1, 2, where one of them can optionally have the shape of an elevated land, the centering of the first and second connection elements 1, 2 and thus between the connection partners is improved.

(31) FIG. 4 illustrates a longitudinal section and a cross section of a connection arrangement according to an exemplary embodiment of the invention. The top longitudinal view depicts the connection arrangement before soldering, and the lower longitudinal view depicts the connection arrangement after soldering.

(32) A plurality of first connection elements 1 and one second connection element 2 establish an electric contact and a mechanical contact both in the connection direction z and in a direction perpendicular to the connection direction z. In more detail, the second connection element 2 is guided by the first connection elements 1 along the connection direction z during connecting the first connection elements 1 with the second connection element 2.

(33) The first connection element 1 is composed of multiple spaced bodies 1 delimiting an accommodation volume for receiving and accommodating the second connection element 2.

(34) The embodiment of FIG. 4 uses a key-lock function, and the first and second connection elements 1, 2 can have a shape of conical cylinders or pillars. The pillars can be placed in such a way that the key-lock function is enabled. It is advantageous if the pillar(s) of at least one of the first and second connection elements 1, 2 has (have) a conical design so that a good centering property is achieved.

(35) It is to be noted that a connection by means of the key-lock function can also achieved by other connection elements except for the pillars.

(36) FIG. 5 illustrates a cross-sectional view and longitudinal sections of a connection arrangement according to an exemplary embodiment of the invention. The longitudinal view at the top right position depicts the connection arrangement before soldering, and the longitudinal view at the lower left position depicts the connection arrangement after soldering.

(37) The embodiment of FIG. 5 is similar to the embodiment of FIG. 4, except for the first and second connection elements 1, 2 which are coated with solderable material 7. As the solderable material 7, soft solders and alloys of copper, silver, zinc, tin, or lead with optional additives of bismuth, indium, cadmium can be used. Also brazing alloys for example of brass or nickel silver are conceivable. The solderable material 7 can be deposited by any method such as sputtering, electroless tin plating or electrolytic deposition of a tin/sliver alloy. On the one hand, such coated copper pillars enable a very reliable key lock connection because a relatively large surface is soldered. On the other hand, a use of smaller solder layers can result in a reduction of a short-circuit bond between connection points. It is to be noted that a connection by means of the key-lock function can also achieved by other coated connection elements except for the pillars.

(38) FIG. 6 illustrates longitudinal sections of a connection arrangement according to an exemplary embodiment of the invention. In this embodiment, the connection arrangement is provided to connect two component carriers 9, 10 to each other, which are for example two printed circuit boards (PCB). Each component carrier 9, 10 comprises a stack 6 having at least one electrically conductive layer structure and/or at least one electrically insulating layer structure, a solder mask 8 at an outermost connection surface of each stack 6, and the connection arrangement in and/or on each stack 6.

(39) The connection arrangement comprises first and second connection elements 1, 2 which are formed as vias in the respective electrically conductive layer structure of the stacks 6. The connection arrangement further comprises a third connection element 3 arranged in the connection direction z between the first connection element 1 and the second connection element 2 for accomplishing a form fit both between the first and third connection elements 1, 3 and between the second and third connection elements 2, 3. In the embodiment of FIG. 6, a form fit is thus indirectly formed between the first and second connection elements 1, 2, whereas, in contrast thereto, the form fit in the embodiments of FIGS. 1 and 3 is rather directly formed between the first and second connection elements 1, 2.

(40) The third connection element 3 is made of or comprises a soldering material and has a convex shape. If the third connection element 3 is a solder ball with a copper core, a defined distance between the component carriers 9, 10 can be set.

(41) The first and second connection elements 1, 2 each have a land with a cooperating surface 11, 21 which is configured for promoting centering of the connection elements 1, 2, 3 upon their connection. The cooperating surfaces 11, 21 of the first and second connection elements 1, 2 each have a concave shape in a section perpendicular to the connection direction, which corresponds to the complementary convex shape of the third connection element 3. Thus, there are dimples in the cooperating surfaces 11, 21, which allow the use of a larger volume of soldering material. At the same time, larger distances in the connection direction z can be bridged between the connection partners.

(42) The first and second connection elements 1, 2 formed as vias can be used as a centering aid when connecting both component carriers 9, 10. The solder masks 8 can be used to create a centering aid for the lands having the concave cooperating surfaces 11, 21.

(43) FIG. 7 illustrates cross-sectional views of connection elements according to exemplary embodiments of the invention. At the left side of FIG. 7, the connection element 1, 2 has a circular cross-section, whereas the connection element 1, 2 at the right side of FIG. 7 has a non-circular cross-section. In more detail, the cross section of the connection element 1, 2 at the right side of FIG. 7 is composed by regularly arranging (in this embodiment four) circular cross sections around a central circular cross section. Thus, the cross section of the connection element 1, 2 at the right side of FIG. 7 is blossom-shaped or shamrock-shaped.

(44) FIG. 8 illustrates a cross-sectional view of connection elements according to an exemplary embodiment of the invention. Each connection element 1, 2 has an alveolar-shaped, honeycomb-shaped or hexagonal cross section. Furthermore, a plurality of connection elements 1, 2 are arranged adjacent to each other. Due to the hexagonal or honeycomb-shaped cross sections, the highest packing density of the connection elements 1, 2 can be achieved. The edges of the alveolar-shaped, honeycomb-shaped or hexagonal cross section can be rounded.

(45) FIG. 9 illustrates cross-sectional views and longitudinal sections of connection elements according to exemplary embodiments of the invention.

(46) At the left upper side of FIG. 9, a cross section of a connection element 1, 2 is shown, and at the left lower side of FIG. 9, a front view of the connection element 1, 2 is shown. The connection element 1, 2 at the left side of FIG. 9 is composed of a plurality of circular or non-circular pillars 20. Some of the pillars are interconnected by elongated lands 21.

(47) At the right upper side of FIG. 9, a cross section of a connection element 1, 2 is shown, and at the right lower side of FIG. 9, a front view of the connection element 1, 2 is shown. The connection element 1, 2 at the right side of FIG. 9 is composed of a star-shaped basis element 23. At each tip of the star-shaped basis element 23, a circular or non-circular pillar 22 is arranged.

(48) The elongated lands 21 and the star-shaped basis element 23, which interconnect the pillars 20 and 22, respectively, can have a contribution to a reduction in the number of rewiring layers.

(49) Due to the non-circular cross sections of the connection elements 1, 2 in the embodiments of FIGS. 2 and 7-9, the mechanical strength, in particular the buckling strength and the section modulus can be improved even when the surface area is equivalent to a circular cross section. Due to a larger circumference, skin effects (i.e. an increased resistance of current-carrying conductors at high frequencies) can be reduced.

(50) In all embodiments of the present invention, at least one of the connection elements 1, 2, 3 can be a pillar, in particular a copper pillar, a via, a land, a solder ball or a ball comprising a central non-solderable body coated with solderable material 7. The pillar can be a conical pillar. The connection joints can include two or more pillars. Ideally, three pillars are preferred in view of the mechanical reliability.

(51) The copper pillar can be built-up on a copper plate, on a copper pad or on a copper foil. The copper pillar can be connected to the copper plate or pad by pressing and spot welding. The copper pillar can otherwise be connected by compression bonding or ultrasonic bonding. The copper pillar can have a tolerance of 6 μm or less. The copper pillar can also be deposited by a galvanic process on the copper foil, pad or plate.

(52) In all embodiments of the present invention, the connection elements 1, 2 (for example the pillars) can have an aspect ratio between the length and a largest or main diameter of more than 1, preferably of more than 2, more preferred more than 3.

(53) Generally, the first and second connection elements 1, 2 can be connected by sound-supported soldering.

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

(55) Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants is possible which use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.