CN209767902U - Component carrier and plate - Google Patents

Abstract

A component carrier (104) and a panel (100) are provided. The component carrier includes: a stack (120) comprising at least one electrically insulating layer structure (122) and/or at least one electrically conductive layer structure (124); a component (106) embedded in the stack (120); and at least one stress-relief opening (132) formed in each of the at least one electrically conductive layer structure (124) arranged in the stack (120) on a side of the component (106) such that a portion (136) of the stack (120) extending from the outer main surface (130) of the component carrier (104) up to the main surface (134) of the component (106) on said side and comprising the at least one stress-relief opening (132) is free of electrically conductive material.

Description

Component carrier and plate

Technical Field

The utility model relates to a part holds carrier and plate.

Background

Against the background of increasing product functionality of component carriers equipped with one or more electronic components, increasing miniaturization of such components and increasing number of components to be mounted on component carriers such as printed circuit boards, increasingly powerful array-like components or packages with several components are used, which have a plurality of contacts or connections, the spacing between which is increasingly smaller. Removal of heat generated by such components and the component carriers themselves during operation becomes an increasingly serious problem. At the same time, the component carrier should be mechanically robust and electrically reliable in order to be able to operate even under severe conditions.

Furthermore, efficient first embedded components are also a problem in component carriers. In particular, component carriers with embedded components show a tendency to warp.

it may be desirable to embed components in the component carrier, but with low warpage.

SUMMERY OF THE UTILITY MODEL

According to an exemplary embodiment of the present invention, there is provided a component carrier, including: a stack comprising at least one electrically insulating layer structure (in particular a plurality of electrically insulating layer structures) and/or at least one electrically conductive layer structure (in particular a plurality of electrically conductive layer structures); a component embedded in the stack; and at least one stress-relief opening formed in each of the at least one electrically conductive layer structure arranged in the stack on a side of the component, such that the portion of the stack extending from the outer main surface of the component carrier up to the main surface of the component (in particular perpendicular to the main surface of the stack) on said side and comprising the at least one stress-relief opening is free of electrically conductive material.

According to another exemplary embodiment of the present invention, a method of manufacturing a component carrier is provided, wherein the method comprises: forming a stack comprising at least one electrically insulating layer structure (in particular a plurality of electrically insulating layer structures) and/or at least one electrically conductive layer structure (in particular a plurality of electrically conductive layer structures); embedding a component in the stack; and at least one stress-relief opening formed in each of the at least one electrically conductive layer structure arranged in the stack on one side of the component, such that a portion of the stack extending from an outer main surface of the component carrier (in particular perpendicular to the main surface of the stack) up to the main surface of the component on said side, which portion comprises the at least one stress-relief opening, is free of electrically conductive material.

According to another exemplary embodiment of the present invention, a panel is provided, comprising an array of a plurality of panel sections, each panel section comprising a component carrier having the above-mentioned features.

In the context of the present application, the term "component carrier" may particularly denote any support structure capable of accommodating one or more components thereon and/or therein to provide mechanical support and/or electrical connection. In other words, the component carrier may be configured as a mechanical and/or electronic carrier for the component. In particular, the component carrier may be one of a printed circuit board, an organic interposer, and an IC (integrated circuit) substrate. The component carrier may also be a hybrid board combining different ones of the above-mentioned types of component carriers.

In the context of the present application, the term "stress relief opening" may particularly denote a recess or a through hole formed in the electrically conductive layer structure at a specifically selected position of the component carrier where significant stresses causing a tendency of the component carrier to warp may occur. The stress relief opening may be a void and/or may be at least partially filled with a dielectric material, but should not contain a conductive material. Such a tendency to warp can be effectively prevented by forming a suitably sized and/or shaped stress relief opening at an appropriate position of the electrically conductive layer of the component carrier above the component.

In the context of the present application, the term "plate" may particularly denote a plate-like structure that may be processed in a batch procedure for the manufacture of a component carrier. After processing, such a panel can be singulated into a plurality of component carriers. For example, the plate may have a size of 12 inches x18 inches.

According to an exemplary embodiment of the invention, a component carrier is provided, comprising a stress relief opening reducing stress acting on the component carrier during manufacturing and/or during use. In order to form one or more stress-relief openings above and/or below the embedded component, each metal layer at least on one side of the component (in particular on the non-connecting side of the component) may be interrupted, for example each metal layer may be correspondingly recessed. Conventionally, component carriers with embedded components are particularly prone to warping. However, it has surprisingly been found that such a tendency to warp can be suppressed by forming one or more non-metallic stress-relieving windows vertically above and/or below the embedded component.

thus, exemplary embodiments of the present invention provide an embedded design concept that actively reduces stress of the package or component carrier and achieves the concept of an embedded component carrier (particularly a printed circuit board, PCB) that would otherwise be infeasible due to reliability or warpage issues. A core advantage of exemplary embodiments of the present invention is the realization of a wider range of embedded component applications.

Further exemplary embodiments of the component carrier, the method and the plate will be explained below.

In one embodiment, the mentioned parts consist exclusively of electrically insulating material, in particular exclusively of electrically insulating material of the at least one electrically insulating layer structure. Thus, the at least one stress relief opening or window may be free of a metallic material such as copper. It has surprisingly been found that the provision of a metal-free window extending uninterrupted from the outer surface of the component carrier up to the upper main surface or the lower main surface of the component carrier effectively reduces the mechanical load exerted on the component carrier in which the component is embedded. The corresponding portion of the stack may correspondingly be constituted by a dielectric material, in particular comprising a resin, such as an epoxy resin, optionally comprising a reinforcement, such as in particular a reinforced glass fiber. In particular, the portion may be copper free. Correspondingly, the one or more stress relief openings may be holes extending through one or more conductive layer structures (such as copper foil).

In another embodiment, the portion is a hollow cavity. Thus, it is also possible to form a hollow cavity from the outer main surface of the component carrier up to the embedded component (e.g. by mechanical drilling, milling or laser cutting), so that one or more through holes are also formed through the metal layer between the outer surface and the component.

In an embodiment, a plurality of stress-relief openings are formed in each of the plurality of electrically conductive layer structures arranged in the stacked structure on said side of the component, such that a portion of the stack extending from the outer main surface of the component carrier up to said main surface of the component comprises the plurality of stress-relief openings and is free of electrically conductive material. Thus, even for complex electrical coupling tasks, it may be accomplished with multiple conductive layer structures, each traversed by a corresponding one of the stress relief openings.

In an embodiment, the plurality of stress relief openings are aligned with each other or may be flush with each other. Illustratively, the edges bounding the plurality of stress-relief openings may exhibit the same annular line when the component carrier is viewed from its upper main surface. In other words, connecting the edges defining the plurality of stress-relief openings together may form a circumferential array of vertically extending straight lines. The stresses can be relieved particularly significantly with the described design.

As an alternative to aligning the stress-relief openings, the stress-relief openings may also overlap and/or one stress-relief opening may appear as part of (i.e. may be located within) another stress-relief opening in a viewing direction perpendicular to the main surface of the component carrier.

In an embodiment, the portion is a cylindrical structure, in particular a cylindrical structure, extending through the respective conductive layer structure. When the plurality of aligned stress-relief openings are circular through-holes, the portion including the circular through-holes is cylindrical in shape.

In an embodiment, the portion is defined by a dielectric material of the stack bounded vertically by the components and the main surfaces of the component carrier, laterally by one or more edges or edge portions of the stress-relief opening, and a corresponding extension into the interior of the component carrier. The latter edges or edge portions may correspond to a circumferential closed loop which is visible when the embedded component is viewed from the outside of the component carrier (and assuming that the electrically insulating layer structure is transparent) in a viewing direction perpendicular to the component carrier and the main surfaces of the component.

In an embodiment, the component carrier comprises at least one further stress-relief opening formed in each of the at least one electrically conductive layer structure arranged in the stack on the opposite side of the component, such that the portion of the stack extending from the other, opposite outer main surface of the component carrier up to the opposite other main surface of the component and comprising the at least one further stress-relief opening on said opposite side is free of electrically conductive material. Thus, both opposite main surfaces of the insert part may be provided with corresponding stress relief openings, such that an efficient stress suppression is effectively achieved on both opposite main surfaces of the part of the insert part carrier.

In an embodiment, a component (e.g., a semiconductor chip) includes at least one pad on one or both of two opposing major surfaces of the component. The at least one solder pad may be formed on the opposite further main surface of the component facing away from the at least one stress relief opening, and in particular only on the opposite further main surface. Thus, the pad side of the component may be used for electrical contact purposes, while the opposite non-pad side may be used for stress relief.

In an embodiment, no further stress relief opening is formed on the side of the component on which the at least one pad is formed. Thus, the flexibility required by the circuit designer to make any desired electrical connections on the pad side of the component is not compromised.

Alternatively, however, it is also possible to form one or more additional stress-relief openings also on the pad side of the component, for example extending between adjacent pads. Furthermore, pads may be formed on two opposite main surfaces of the component, and one or more stress relief openings are also formed between one or both of these main surfaces and the outer main surface of the component carrier.

In an embodiment, the at least one stress relief opening is completely circumferentially delimited by the material of the respective conductive layer structure, in particular a through hole, more particularly a circular through hole. It is also possible that the at least one conductive layer structure is a continuous layer having a single via forming a designated one of the at least one stress relief opening. In other words, the stress relief opening may be formed as an annular closed structure. Thus, for example, a continuous metal foil may be provided with one or more internal through holes forming stress relief openings.

In an embodiment, the ratio between the area of the respective (in particular each) of the stress-relief openings and the area of the main surface of the component is at least 10%, in particular at least 20%. It has been found that a significant stress relief can already be obtained when at least 10% of the respective main surface of the component is connected to a portion extending up to the outer main surface of the component carrier and comprising the one or more stress relief openings. When the local area is at least 20%, even excellent stress relieving performance can be obtained. Preferably, the ratio may be less than 90%. Thus, an area of an individual one of the stress relief openings may be smaller than an area of the major surface of the component.

In an embodiment, the at least one stress relief opening is configured for reducing warpage-inducing stresses exerted on the component carrier. The material, position and/or shape of the stress-relief opening and the corresponding above-mentioned portion of the stack are design parameters in this context.

In a preferred embodiment, the component carrier comprises at least one stress relief structure arranged in the stack and at least partially in a central plane of the component. Accordingly, the panel may comprise at least one stress relief structure arranged at least partially in the connecting line connecting at least two of the connection parts. In the context of the present application, the term "stress-relief structure" may particularly denote a physical structure integrated in the panel or the component carrier (on the basis of which the component carrier may be manufactured) at a specific selected location where significant stresses causing a tendency of the component carrier to warp may occur. Such a tendency to warp can be effectively prevented by integrating material and/or appropriately shaped stress relief structures at appropriate locations of the component carrier or panel. According to an exemplary embodiment of the present invention, a panel and a component carrier manufactured on the basis of the panel are provided, which comprise a stress relief structure reducing the stress acting on the component carrier during manufacturing and/or during use. Conventionally, component carriers with embedded components are particularly susceptible to such warping. Surprisingly, however, it has been found that integrating stress-relief structures at virtual (in particular horizontal) connecting lines connecting different components of different component carriers of a panel can suppress this tendency to warp.

In a very preferred embodiment, the component carrier and/or the plate is provided with a combination of at least one stress-relief opening and at least one stress-relief structure as described herein. Therefore, it is possible to efficiently alleviate the stress on the vertical axis in the horizontal plane and perpendicular thereto.

In an embodiment, the at least one stress relief structure is configured to reduce warpage-inducing stresses exerted on the component carrier. The material, position and/or shape of the stress-relief structure is in this context a design parameter.

in an embodiment, at least a portion of the at least one stress relieving structure is shaped as a sheet extending perpendicular to the main surface of the component carrier. For example, a sheet-like cavity or slit may be formed in the stack. Such recesses may then be filled with a conductive material, such as a metal, in particular copper. Such a filling procedure may be accomplished, for example, by electroplating.

In an embodiment, at least a portion of the at least one stress relief structure comprises a plurality of parallel posts extending perpendicular to a major surface of the component carrier. For example, the via may be formed by laser drilling or mechanical drilling, and may then be filled with a conductive material such as a metal, particularly copper.

in an embodiment, at least a portion of the at least one stress relief structure comprises or consists of copper. Any other suitable metallic material may also be used. In another embodiment, the stress-relieving structure may also be constructed of a plastic material or a material having plastic deformation properties.

In an embodiment, at least a portion of the at least one stress mitigating structure may have a plastic stress behavior. It is also possible that at least a portion of the at least one stress relief structure may act as a low modulus elastomeric stress buffer.

In an embodiment, the coordinates of the center of gravity of the at least one stress relieving structure in a direction perpendicular to the main surface of the component carrier correspond to the coordinates of the center of gravity of the component in a direction perpendicular to the main surface of the component carrier. In other words, the height level of the center of gravity of the stress relieving structure and the height level of the center of gravity of the component may be the same, and both may be located on the above-mentioned connecting line. It has been found that the stress propagation occurs mainly in the horizontal direction of the plate or component carrier at the above-mentioned height level and can be suppressed by the described geometry.

In an embodiment of the panel, at least a part of the at least one stress relief structure is arranged in a transition region between the component carriers of the panel. When positioned in the transition region between the panel sections or component carriers, the unused surface area of the panel may be used to improve warpage. At the same time, the component carrier can be made very compact, since in the described embodiment the component carrier itself does not need to comprise stress-relief structures.

In an embodiment of the panel, a part of the stress relief structure is at least partially arranged in a further connecting line connecting at least two of the components and extending perpendicular to the connecting line. Thus, the stress relief function can be achieved in two mutually perpendicular directions in a plane defined by the plate member (more precisely, defined by its two opposite main surfaces). The stress-relief structures may be arranged in two orthogonal directions, thereby further improving the stress-relief effect in the component carrier and the panel.

The component may be selected from the group consisting of: a non-conductive inlay, a conductive inlay (such as a metal inlay, preferably comprising copper or aluminum), a heat transfer unit (e.g., a heat pipe), a light guide element (e.g., a light guide or light guide connector), an electronic component, or a combination thereof. For example, the component may be an active electronic component, a passive electronic component, an electronic chip, a storage device (e.g. a DRAM or another data storage), a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface element, a voltage converter (e.g. a DC/DC converter or an AC/DC converter), a cryptographic component, a transmitter and/or receiver, an electromechanical transducer, a sensor, an actuator, a micro-electromechanical system (MEMS), a microprocessor, a capacitor, a resistor, an inductance, a battery, a switch, a camera, an antenna, a logic chip, a light guide and an energy harvesting unit. However, other components may be embedded in the component carrier. For example, a magnetic element may be used as the component. Such magnetic elements may be permanent magnetic elements (such as ferromagnetic elements, antiferromagnetic elements or ferrimagnetic elements, e.g. ferrite based structures) or may be paramagnetic elements. However, the component may also be another component carrier, for example a plate-in-plate configuration. The one or more components may be surface mounted on the component carrier and/or may be embedded in the component carrier. In addition, components other than the above-described components may be used as the components.

In an embodiment, the plate or component carrier comprises a stack of at least one electrically insulating layer structure and at least one electrically conductive layer structure. For example, the plate or component carrier may be a laminate of the above-described electrically insulating layer structure and electrically conductive structure, in particular formed by applying mechanical pressure, if necessary supported by thermal energy. The stack may provide a plate-like component carrier which is capable of providing a large mounting surface for further components, but which is still very thin and compact. The term "layer structure" may particularly denote a continuous layer, a patterned layer or a plurality of non-continuous islands in a common plane.

In an embodiment, the component carrier is shaped as a plate. This contributes to a compact design, but wherein the component carrier provides a large base for mounting components thereon. In addition, a bare chip, which is an example of an embedded electronic component in particular, can be easily embedded in a thin board such as a printed circuit board owing to its small thickness.

In one embodiment, the component carrier is configured as one of the group consisting of a printed circuit board and a substrate (in particular an IC substrate).

In the context of the present application, the term "printed circuit board" (PCB) may particularly denote a component carrier (which may be plate-like (e.g. planar), three-dimensionally curvilinear (e.g. when manufactured using 3D printing) or which may have any other shape) which is formed by laminating several electrically conductive layer structures together with several electrically insulating layer structures, e.g. by applying pressure, if desired with simultaneous supply of thermal energy. As regards the preferred material for PCB technology, the electrically conductive layer structure is made of copper, whereas the electrically insulating layer structure may comprise resin and/or glass fibres, so-called prepreg or FR4 material. The individual conductive layer structures can be connected to one another in a desired manner by forming through-holes through the laminate, for example by laser drilling or mechanical drilling, and by filling the through-holes with a conductive material, in particular copper, so that the through-holes are formed as through-hole connections. In addition to one or more components that may be embedded in a printed circuit board, printed circuit boards are typically configured to receive one or more components on one surface or two opposing surfaces of a plate-like printed circuit board. The components may be attached to the respective major surfaces by soldering. The dielectric portion of the PCB may include a resin with reinforcing fibers, such as glass fibers.

In the context of the present application, the term "substrate" may particularly denote a small component carrier having substantially the same size as the component (particularly the electronic component) to be mounted thereon. More specifically, a baseplate can be understood as a carrier for electrical connections or electrical networks and a component carrier comparable to a Printed Circuit Board (PCB), although the connection density in the lateral and/or vertical arrangement is much higher. The lateral connections are, for example, conductive paths, while the vertical connections may be, for example, boreholes. These lateral and/or vertical connections are arranged within the substrate and may be used to provide electrical and/or mechanical connection of a housed or unreceived component (such as a bare wafer), in particular an IC chip, to a printed circuit board or an intermediate printed circuit board. Thus, the term "substrate" also includes "IC substrates". The dielectric portion of the substrate may include a resin with reinforcing spheres, such as glass spheres.

In an embodiment, the dielectric material of the at least one electrically insulating layer structure comprises at least one of the group consisting of: resins such as reinforcing or non-reinforcing resins, for example epoxy resins or bismaleimide triazine resins, more particularly FR-4 or FR-5, cyanate esters, polyphenylene derivatives, glass (in particular glass fibers, multilayer glass, glassy materials), prepregs, polyimides, polyamides, Liquid Crystal Polymers (LCP), epoxy based laminates, polytetrafluoroethylene (Teflon), ceramics and metal oxides. Reinforcing materials such as meshes, fibers or spheres, for example made of glass (multiple layers of glass), may also be used. While prepreg or FR4 is generally preferred, other materials may be used. For high frequency applications, high frequency materials such as polytetrafluoroethylene, liquid crystal polymers, and/or cyanate ester resins may be implemented in the component carrier as an electrically insulating layer structure.

In an embodiment, the electrically conductive material of the at least one electrically conductive layer structure comprises at least one of the group consisting of: copper, aluminum, nickel, silver, gold, palladium, and tungsten. While copper is generally preferred, other materials or coated forms thereof are possible, particularly coated with a superconducting material such as graphene.

In an embodiment, the component carrier is a laminate type body. In this embodiment, the semi-finished product or component carrier is a composite of a multilayer structure which is stacked and joined together by applying a compressive force, if desired with heat.

The above aspects 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.

Drawings

Fig. 1A and 1B show a cross-sectional view and partial details, respectively, of a component carrier with stress-relief openings according to an exemplary embodiment of the present invention.

Fig. 2 shows a cross-sectional view of a component carrier with a double-sided stress relief opening according to another exemplary embodiment of the present invention.

Fig. 3 shows a cross-sectional view of an array of panels comprising a component carrier according to an exemplary embodiment of the present invention, wherein stress-relief openings and stress-relief structures are provided.

Fig. 4 shows a plan view of a panel comprising an array of component carriers according to an exemplary embodiment of the present invention.

Fig. 5-8 show plan views of individual plate sections of the plate of fig. 4 showing stress-relief structures, according to various exemplary embodiments of the present invention.

Detailed Description

the illustration in the drawings is schematically. In different drawings, similar or identical elements are provided with the same reference signs.

Before describing exemplary embodiments in more detail, with reference to the accompanying drawings, some basic considerations will be summarized, based on which exemplary embodiments of the present invention are developed.

According to an embodiment, a component carrier (such as a PCB, printed circuit board) with embedded components is provided with high reliability and low mechanical stress.

mechanical stresses inside embedded PCB packages often cause serious problems such as warpage, especially with components having ceramic or silicon surfaces.

In particular, by a suitable design of at least a part of adjacent layers of the component carrier, in particular of the component area of the PCB, a very effective stress relief can be achieved. Based on the studies of the present inventors, it has been possible to significantly improve the reliability of the package by ensuring copper relief design on each layer (in particular each metal layer) in the embedded component region. Based on these studies, excellent results were obtained when the copper of such a conductive layer structure was spatially dug out at least 20% of the component area on each layer by implementing one or more stress relief openings. However, significant improvements can already be obtained when the above-mentioned percentage of area provided by the stress relief openings is at least 10%.

Based on long-term research, exemplary embodiments of the present invention have found a way to additionally reduce stress by preparing an embedded PCB design concept. This solution provides an architecture that significantly improves the reliability of the package or component carrier with little effort. More specifically, mitigation of horizontal accumulated stress may be achieved by a plastic stress barrier or stress mitigation structure. In particular, it may be advantageous to implement a barrier layer which may be made of plastic or metal and which may partially or completely eliminate the accumulated stress in the center of the package or component carrier. The stress relief structure may be made of a plastically deformable material. By taking such measures, the buckling behavior of the embedded PCB or more generally of the component carrier with embedded components may be reduced or avoided. It is highly advantageous that reliability and warpage performance can be significantly improved to significantly extend the range of applications for embedded components. This can be achieved substantially without additional effort.

The inventors have carried out reliability tests which show an improvement in particular in the following respects: without the stress relief design, failure occurred after 3 reflow cycles. With the stress relief design, the product was still acceptable even after 15 reflow cycles. The results were confirmed over 10 batches and were repeated.

fig. 1A illustrates a cross-sectional view of a component carrier 104 having a copper-free stress relief opening 132 in a conductive layer structure 124 vertically above an embedded component 106 according to an exemplary embodiment of the present invention.

The component carrier 104 is shown configured as a laminate type plate Printed Circuit Board (PCB). The component carrier 104 includes a laminate stack 120 including a plurality of electrically insulating layer structures 122, which may include a resin (such as an epoxy resin), optionally including reinforcing particles (e.g., fiberglass). In addition, stack 120 includes a plurality of conductive layer structures 124, which may be continuous copper foil, patterned copper foil, and/or copper-filled vias (e.g., laser vias and/or mechanically drilled vias). The layer structures 122, 124 may be connected to each other by lamination, i.e. by applying heat and/or pressure.

One or more components 106 may be embedded in the stack 120. For example, the component 106 shown in FIG. 1A may be a semiconductor chip, such as a processor or memory.

As can be seen from fig. 1A, in this case, three stress relaxation openings 132 as through-holes are formed in each of the conductive layer structures 124 arranged in the stacked body 120 on the upper side of the component 106. As a result, a portion 136 (dashed line in fig. 1A) of the stack 120 is formed or defined that extends from the outer upper major surface 130 of the component carrier 104 up to the upper major surface 134 of the component 106 and includes the stress relief opening 132. Portion 136 is bounded laterally by an imaginary vertical sidewall 183 defined by the laterally narrowest extent of stress-relief opening 132. The upper end of the portion 136 is defined by the upper major surface 130 of the component carrier 104. The lower end of the portion 136 is defined by the upper major surface 134 of the member 106. The lateral extent of portion 136 corresponds to a vertical line or sidewall 183 associated with a completely uninterrupted dielectric stack portion above component 106. In the illustrated embodiment, the conductive layer structures 124 over the upper major surface 134 of the component 106 are each a continuous layer having only a single via forming one of the designated stress relief openings 132. The entire portion 136 is free of electrically conductive material of the electrically conductive layer structure 124 and, in the embodiment shown, consists only of electrically insulating material of the electrically insulating layer structures 122 of the stack 120. Alternatively, the portion 136 may be or may include a hollow cavity (not shown). The outermost two of the three stress relief openings 133 are vertically aligned with each other, i.e., have sidewalls that are vertically flush with each other. The lowermost stress relief opening 133 is wider.

As also shown in fig. 1A, the component 106 includes a pad 138 only on the lower major surface 134 of the component 106 that faces away from the stress-relief opening 132 in the upper portion of the stack 120. No additional stress relief openings are formed on the bottom or underside of feature 106 on which bond pads 138 are formed. Accordingly, the portion of the stack 120 corresponding to the side of the component 106 having the pad 138 may be referred to as a connection side. Correspondingly, the portion of the stack 120 above the padless major surface 134 of the component 106 may be referred to as the non-connecting side and open upward via the stress relief opening 132.

As can be seen from detail 171 in fig. 1B, which shows a plan view, the stress-relief openings 132 may be completely delimited circumferentially by the material of the respective conductive layer structure 124, so as to form through-holes, in the embodiment shown circular through-holes. Still referring to detail 171, the ratio between the area A1 of stress relief opening 132 shown and the area A2 of rectangular upper major surface 134 of member 106 therein may preferably be at least 10%, more preferably at least 20%. In other words, it is preferable to gouge at least 10% of the part area per layer. Advantageously, such a sufficiently large stress relief opening 132 may effectively reduce warpage-inducing stresses exerted on the component carrier 104.

Embedding the component 106 in the component carrier 104 may be performed with reduced stress using the architecture described with reference to fig. 1A implementing copper relief openings. More precisely, the stress in the xy-plane can be reduced. The xy plane may be defined as a plane corresponding to major surfaces 130, 134 and may be oriented perpendicular to the plane of the paper in fig. 1A, while including a horizontal axis according to fig. 1A. The xy plane stress is schematically indicated in fig. 1A with reference number 177. Further, fig. 1A also indicates an area a2 of the component with reference numeral 179, while an area a1 of the stress relief opening corresponds to reference numeral 181 in fig. 1A.

Fig. 2 illustrates a cross-sectional view of a component carrier 104 having a stress relief opening 132 according to another exemplary embodiment of the present invention.

Advantageously, the component carrier 104 of fig. 2 further comprises further stress-relief openings 133 formed in each of the electrically conductive layer structures 124 of the stack 120 arranged below the lower main surface 134 of the component 106. Thus, a further portion 137 (dashed line in fig. 2) of the stack 120 is formed which extends from the lower main surface 130 of the component carrier 104 up to the lower main surface 134 of the component 106, which further portion comprises a further stress relief opening 133 which is also free of electrically conductive material. Again, portion 137 is defined as a completely uninterrupted dielectric vertical window between member 106 and outer major surface 130, and is bounded by the laterally narrowest limits of stress-relief openings 132.

Even more preferably, the component carrier 104 of fig. 2 may optionally additionally include stress-relief structures 108 disposed in the stack 120 and at least partially within the central plane 112 of the component 106. In particular, by combining the stress relief opening 132 and the stress relief structure 108, very advantageous properties in terms of stress relief may be obtained. The construction and function of the stress relief structure 108 will be described below with reference to fig. 3-8.

Fig. 3 shows a cross-sectional view of a panel 100 comprising an array of component carriers 104 according to an exemplary embodiment of the present invention. Both the stress-relief opening 132 and the stress-relief structure 108 are provided in this embodiment for effectively suppressing stress and preventing warpage. The panel 100 may be used to mass produce the component carrier 104. After the manufacturing process is complete, the sheet 100 may be separated into individual cards or component carriers 104 by singulation (e.g., by cutting or etching) at the singulation lines 163. The component carrier 104 may be a laminated flat plate-shaped Printed Circuit Board (PCB).

The plate 100 comprises a matrix-like array of a plurality of plate sections 102 arranged in rows and columns (compare fig. 4). Each plate section 102 corresponds to the component carrier 104 or a preform of the component carrier 104 (i.e. a semi-finished structure in the form of a part of the plate 100 which can have the function of the component carrier 104 after the manufacturing process is completed). A respective component of the plurality of components 106 (in particular semiconductor chips, e.g. bare wafers) is embedded in each of the plate section 102 or the corresponding component carrier 104. The solder pads 138 of the components 106 are connected to the outside of the respective component carrier 104 by vertical through connections 165, for example copper plated vias. Such a component carrier 100 with embedded components 106 is particularly prone to warping due to high mechanical stresses.

Two respective stress-relief structures of the plurality of stress-relief structures 108, for example made of copper, are arranged between two respective juxtaposed component carriers 104. The stress relief structure 108 is located in and passes through a virtual connection line 110 connecting the components 106 of the component carriers 104. Further, the stress relief structure 108 is partially disposed within and thus passes through a central plane 112 of the component 106. According to fig. 3, the stress-relief structure 108 extends vertically, i.e. perpendicular to the main surface 130 of the plate-like plate member 100. More specifically, the coordinates of the center of gravity of the stress mitigating structure 108 in the vertical direction perpendicular to the horizontal main surface 130 of the board 100 are the same or substantially the same as the coordinates of the center of gravity of the component 106 in the vertical direction perpendicular to the horizontal main surface 130 of the board 100. Descriptively, stress may have a particular effect in the horizontal direction at the center of gravity of the insert part 106 when the mentioned geometrical conditions are achieved, and stress propagation and stress induced artefacts, such as warping, may be prevented. With this arrangement, stress relief structure 108 enables warpage-inducing stresses to be reduced on plate segment 102. Preferably, the lateral distance d between the side wall of the component 106 and the adjacent stress relief structure 108 may be less than 10 mm.

Each of the component carriers 104 comprises a stack 120 comprising an electrically insulating layer structure 122, such as prepreg or FR4, and an electrically conductive layer structure 124, for example made of copper, see detail 161. The designated parts 106 of the respective part carriers 104 are embedded in the stack 120. Some of the stress relief structures 108 are disposed in the stack 120 and partially within the central plane 112 of the component 106. Thus, embedding with reduced stress may be achieved due to the features having elastic stress characteristics. For example, copper plated structures, such as vias, trenches, cavities, may be formed in the stack 120 to act as plastic stress buffers or stress relief structures 108 to sever the cumulative stress chain of the production format, i.e., the panel 100.

Fig. 4 shows a plan view of a panel 100 comprising an array of component carriers 104 according to an exemplary embodiment of the present invention. The stress-relief opening 132 and the corresponding conductive layer structure 124 are omitted from fig. 4 for clarity. Fig. 4 shows that a portion of the stress relief structure 108 is disposed in the plate section 102, while another portion of the stress relief structure 108 is disposed in the transition region 114 between the plate sections 102.

A plastic stress relief buffer or stress relief structure 108 may be introduced to sever the stress chain of the embedded substrate or component 106 in the horizontal plane. The stress may be reduced when implementing at least one plastic property feature in at least one direction, preferably in two perpendicular directions, between successive chains of insert parts 106. The plastic property features may be, for example, copper plated vias or trenches, or the plastic property features may be made of other materials that have plastic stress behavior.

Fig. 5-8 illustrate plan views of various plate sections 102 of the plate 100 of fig. 4 showing stress-relief structures 108, according to various exemplary embodiments of the present invention.

Referring to fig. 5, the stress relief structure 108 is shaped as a sheet 116 extending perpendicular to the component 106. A portion of the stress relief structure 108 extends along a connection line 110 and another portion of the stress relief structure 108 extends along another connection line 111. This enhances the stress relief capability of the singulated component carrier 104 and the panel 100 as a whole. Thus, plating baths in the core, build-up and/or outer layers within the card region may be provided as stress relief structures 108.

Referring to fig. 6, the stress relief structure 108 includes a plurality of parallel columns 118 extending vertically through the plate 100. Thus, plated holes in the core layer, build-up layer, and/or outer layer within the card region may be provided as stress relief structures 108. According to fig. 6, the stress relief structure 108 extends along only a single connection line 110.

Referring to fig. 7, the stress-relief structures 108 are formed in a similar manner as according to fig. 5, however now outside the component carriers 104 and in the transition regions 114 between adjacent component carriers 104. Plating baths in the core/build-up/outer layers outside the card area may be provided as stress relief structures 108.

Referring to fig. 8, the stress-relief structures 108 are formed in a similar manner as according to fig. 6, however now outside the component carriers 104 and in the transition regions 114 between adjacent component carriers 104. Further, according to fig. 8, the stress mitigation structure 108 functions in two dimensions, rather than in one dimension according to fig. 6. Plated holes in the core, build-up and/or outer layers outside the card area may be provided as stress relief structures 108.

It should be noted that the term "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. In addition, elements described in association with different embodiments may be combined.

It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.

The practice of the invention is not limited to the preferred embodiments shown in the drawings and described above. On the contrary, there are numerous variations that use the illustrated solutions and principles according to the invention, even in the case of embodiments that are fundamentally different.

Claims (36)

1. A component carrier, characterized in that the component carrier (104) comprises:

A stack (120) comprising at least one electrically insulating layer structure (122) and/or at least one electrically conductive layer structure (124);

A component (106) embedded in the stack (120);

At least one stress-relief opening (132) formed in each of the at least one electrically conductive layer structure (124) arranged in the stack (120) on one side of the component (106) such that a portion (136) of the stack (120) extending on the side from an outer main surface (130) of the component carrier (104) up to a main surface (134) of the component (106) and including the at least one stress-relief opening (132) is free of electrically conductive material.

2. The component carrier according to claim 1, wherein the portion (136) consists solely of an electrically insulating material.

3. The component carrier according to claim 1, wherein the portion (136) consists solely of the electrically insulating material of the at least one electrically insulating layer structure (122).

4. The component carrier according to claim 1, wherein the portion (136) is a hollow cavity.

5. The component carrier according to claim 1, wherein a plurality of stress-relief openings (132) are formed in each of a plurality of electrically conductive layer structures (124) arranged in the stack (120) on the side of the component (106), such that the portion (136) of the stack (120) extending from the outer main surface (130) of the component carrier (104) up to the main surface (134) of the component (106) comprises the plurality of stress-relief openings (132) and is free of electrically conductive material.

6. The component carrier according to claim 5, wherein at least two of the plurality of stress relief openings (133) are aligned with each other.

7. The component carrier according to claim 5, wherein all of the plurality of stress-relief openings (133) are aligned with each other.

8. The component carrier according to claim 1, wherein the portion (136) is a cylindrical structure with vertical side walls (183).

9. The component carrier according to claim 1, wherein the portion (136) is a cylindrical structure having vertical side walls (183).

10. The component carrier according to claim 1, comprising at least one further stress-relief opening (133) which is formed in each of the at least one electrically conductive layer structure (124) arranged in the stack (120) on the opposite side of the component (106) such that a further portion (137) of the stack (120) extending from the further outer main surface (130) of the component carrier (104) on the opposite side up to the further main surface (134) of the component (106) and comprising the at least one further stress-relief opening (133) is free of electrically conductive material.

11. The component carrier according to claim 1, wherein the component (106) comprises at least one solder pad (138).

12. The component carrier according to claim 11, wherein the at least one solder pad is on a further main surface (134) of the component (106) facing away from the at least one stress-relief opening (132).

13. The component carrier according to claim 11, wherein the at least one solder pad is only on a further main surface of the component (106) facing away from the at least one stress-relief opening (132).

14. The component carrier according to claim 11, wherein no stress relief opening is formed on the side of the component (106) on which the at least one solder pad (138) is formed.

15. The component carrier according to claim 1, wherein the at least one stress-relief opening (132) is completely circumferentially delimited by the material of the respective electrically conductive layer structure (124).

16. The component carrier of claim 15, wherein the at least one stress-relief opening is a through-hole extending through the respective conductive layer structure.

17. The component carrier of claim 15, wherein the at least one stress-relief opening is a circular through-hole extending through the respective conductive layer structure.

18. The component carrier according to claim 1, wherein the at least one electrically conductive layer structure (124) is a continuous layer having a single through hole forming a designated one of the at least one stress relief opening (132).

19. The component carrier according to claim 1, wherein a ratio between an area (a1) of a respective one of the stress relief openings (132) and an area (a2) of the main surface (134) of the component (106) is at least 10%.

20. The component carrier according to claim 1, wherein a ratio between an area (a1) of a respective one of the stress relief openings (132) and an area (a2) of the main surface (134) of the component (106) is at least 20%.

21. The component carrier according to claim 1, wherein a ratio between an area (a1) of each individual one of the stress relief openings (132) and an area (a2) of the main surface (134) of the component (106) is at least 10%.

22. The component carrier according to claim 1, wherein a ratio between an area (a1) of each individual one of the stress relief openings (132) and an area (a2) of the main surface (134) of the component (106) is at least 20%.

23. The component carrier according to claim 1, wherein the at least one stress relief opening (132) is configured for reducing warpage-inducing stresses exerted on the component carrier (104).

24. The component carrier according to claim 1, comprising at least one stress relief structure (108) arranged in the stack (120) and at least partially within a central plane (112) of the component (106).

25. The component carrier according to claim 24, wherein the at least one stress relief structure (108) is configured for reducing warpage-inducing stresses exerted on the component carrier (104).

26. The component carrier according to claim 24, wherein at least a portion of the at least one stress-relief structure (108) is shaped as a sheet (116) extending perpendicular to the main surface (130) of the component carrier (104) and/or comprises a plurality of parallel posts (118) extending perpendicular to the main surface (130) of the component carrier (104).

27. The component carrier according to claim 24, wherein at least a portion of the at least one stress relief structure (108) has plastic stress behavior.

28. The component carrier according to claim 24, characterized in that the coordinates of the center of gravity of the at least one stress-relief structure (108) in a direction perpendicular to the main surface (130) of the component carrier (104) correspond to the coordinates of the center of gravity of the component (106) in a direction perpendicular to the main surface (130) of the component carrier (104).

29. The component carrier of claim 1, wherein the component carrier comprises at least one of the following features:

The at least one conductive layer structure (124) comprises one of the group consisting of: copper, aluminum, nickel, silver, gold, palladium and tungsten, any of the mentioned materials optionally coated with a superconducting material;

The at least one electrically insulating layer structure (122) comprises one of the group consisting of: a resin; a cyanate ester; a polyphenylene derivative; glass; a prepreg material; a polyimide; a polyamide; a liquid crystalline polymer; an epoxy-based laminate film; polytetrafluoroethylene; a ceramic; and a metal oxide;

The component (106) is selected from the group consisting of: electronic components, non-conductive and/or conductive inlays, heat transfer units, energy harvesting units, active electronic components, passive electronic components, electronic chips, storage devices, filters, integrated circuits, signal processing components, power management components, optoelectronic interface elements, voltage converters, cryptographic components, transmitters and/or receivers, electromechanical transducers, actuators, micro-electromechanical systems, microprocessors, capacitors, resistors, inductors, accumulators, switches, cameras, antennas, magnetic elements, light guide elements, further component carriers, and logic chips;

The component carrier (104) is shaped as a plate;

The component carrier (104) is configured as a printed circuit board or substrate.

30. The component carrier of claim 29, wherein the superconducting material is graphene.

31. The component carrier of claim 29, wherein the resin is a reinforced or non-reinforced resin.

32. The component carrier of claim 29, wherein the resin is an epoxy resin, a bismaleimide-triazine resin, FR-4, or FR-5.

33. A panel, characterized in that the panel comprises an array of a plurality of panel sections (102), each comprising a component carrier (104) according to claim 1.

34. The panel as claimed in claim 33, wherein the panel comprises at least one stress relief structure (108) arranged at least partially in a connecting line (110) connecting at least two of the components (106).

35. The panel according to claim 34, characterized in that at least a part of the at least one stress relief structure (108) is arranged in a transition region (114) between the component carriers (104).

36. A plate according to claim 34, characterized in that a part of the stress relief structure (108) is arranged at least partly in a further connection line (111) connecting at least two of the components (106) and extending perpendicular to the connection line (110).