Patent Application
20200163223
This application claims the benefit of the filing date of Chinese Patent Application No. 201811384918.5, filed Nov. 20, 2018, the disclosure of which is hereby incorporated herein by reference.
Embodiments of the invention generally relate to a method of manufacturing a component carrier, to the component carrier, and to a semi-finished product.
In the context of growing product functionalities of component carriers equipped with one or more electronic components and increasing miniaturization of such electronic components as well as a rising number of electronic components to be mounted on the component carriers such as printed circuit boards, increasingly more powerful array-like components or packages having several electronic components are being employed, which have a plurality of contacts or connections, with ever smaller spacing between these contacts. Removal of heat generated by such electronic components and the component carrier itself during operation becomes an increasing issue. At the same time, component carriers shall be mechanically robust and electrically reliable so as to be operable even under harsh conditions. In particular, efficiently embedding an electronic component into a component carrier and later-on electrically connecting said embedded electronic component remains a challenge.
However, the prior art methods suffer from warpage issues, especially in the case when large dies are embedded. In order to overcome this issue, very thick core structures are used, even though thin core design provide many advantages over thick core structures, e.g. with respect to space requirements and heat dissipation. But in the case of thin core processing there is a high risk of yield drop regarding the process described above. Furthermore, thermal management is problematic due to heat produced by the embedded chip. This is especially true in the thick core structure, wherein it is more difficult to efficiently dissipate the produced heat.
There may be a need to provide a method of manufacturing a component carrier with an embedded component in an efficient and robust manner.
A method of manufacturing a component carrier, the component carrier, and a semi-finished product according to the independent claims are provided.
According to an exemplary embodiment of the invention, a method of manufacturing a first component carrier and a second component carrier is provided. The method comprising: i) providing a separation component comprising a first separation surface and a second separation surface being opposed to the first separation surface, ii) coupling a first base structure having a first cavity with the first separation surface, iii) coupling a second base structure having a second cavity with the second separation surface, iv) placing a first electronic component in the first cavity, v) connecting the first base structure with the first electronic component to form the first component carrier, vi) placing a second electronic component in the second cavity, vii) connecting the second base structure with the second electronic component to form the second component carrier, viii) separating the first component carrier from the first separation surface of the separation component, and ix) separating the second component carrier from the second separation surface of the separation component.
According to a further exemplary embodiment of the invention, a component carrier is provided. The component carrier comprises: i) a layer stack comprising electrically conductive layer structures and electrically insulating layer structures, wherein at least one electrically insulating layer structure is a low Young modulus layer structure formed of a low Young modulus material (in particular with a Young modulus of less than 10 GPa) and wherein the layer stack is at least partially formed as a redistribution structure, and ii) an electronic component embedded in a cavity of the layer stack and electrically connected with the redistribution structure such that a first electric contact of the electronic component is transferred via the redistribution structure to a second electric contact at a main surface of the layer stack, wherein the second electric contact is larger than the first electric contact. Hereby, the electronic component is arranged between (in particular directly between) the low Young modulus layer structure and the redistribution structure.
According to a further exemplary embodiment of the invention, a semi-finished product is provided. The semi-finished product comprises: i) a separation component having a first separation surface and a second separation surface, wherein the second separation surface is opposed to the first separation surface, ii) a first component carrier or first base structure comprising a first electronic component placed (in particular embedded) in a cavity of the first component carrier or first base structure, wherein the first component carrier or first base structure is coupled with the first separation surface, iii) a second component carrier or second base structure comprising a second electronic component placed (in particular embedded) in a cavity of the second component carrier or second base structure, wherein the second component carrier or second base structure is coupled with the second separation surface, iv) a first electrically insulating layer formed between the first separation surface and the first component carrier or first base structure such that the first component carrier or first base structure is attached to the first electrically insulating layer, and v) a second electrically insulating layer formed between the second separation surface and the second component carrier or second base structure such that the second component carrier or first base structure is attached to the second electrically insulating layer.
In the context of the present application, the term “component carrier” may particularly denote any support structure which is capable of accommodating one or more components thereon and/or therein for providing mechanical support and/or electrical connectivity. In other words, a component carrier may be configured as a mechanical and/or electronic carrier for components. In particular, a component carrier may be one of a printed circuit board (PCB), an organic interposer, a substrate-like-PCB (SLP), and an IC (integrated circuit) substrate. A 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 component carrier may comprise a layer stack (comprising e.g. at least one electrically insulating layer structure and at least one electrically conductive layer structure) and an electronic component embedded in a cavity of the layer stack. In another embodiment, the component carrier may comprise a base structure connected to an electronic component embedded in a cavity of the base structure. The base structure may be a layer stack or a single layer.
In the context of the present application, the term “base structure” may refer to a preform of a component carrier. For example, the base structure may comprise a layer stack or merely one electrically insulating core structure. Furthermore, the base structure may comprise electrically conductive structures such as vias or layers. Additionally, the base structure comprises a cavity for accommodating an electronic component. The cavity may be formed in a layer stack of the base structure. In another embodiment, the base structure may comprise a hole in a core structure and a temporary carrier may be arranged below the hole. In this manner, a cavity may be formed into which the electronic component could be placed. At a later process stage, e.g. after embedding the electronic component with electrically insulating material, the temporary carrier may be removed. Alternatively, a coreless structure may be used.
In the context of the present application, the difference between a base structure and a component carrier may be seen in that the electronic component, placed into a cavity of the base structure, is connected to said base structure or not. The term “connected” may hereby refer to a physical connection. When the electronic component is merely placed into the cavity, there is not yet a connection present, but a further process step is needed. For example, the electronic component may be embedded in the base structure by further electrically insulating material. In this manner, the electronic component and the base structure would be physically connected. According to a further embodiment, the electronic component may be electrically connected to the base structure, for example by an interconnection via or any other electrically conductive (layer) structure. Also in this manner, there would be a physical connection that goes beyond mere placing. According to a preferred embodiment, the electronic component is at least partially embedded in an additional electrically insulating layer. Said layer may comprise prepreg, i.e. resin material in an uncured state, and may be pressed into the electrically insulating layer in order to be at least partially embedded. Also thereby, the electronic component may be connected to the base structure such that a component carrier is obtained.
In the context of the present application, the term “separation component” may refer to any component that is suitable as a temporary carrier for at least two base structures (i.e. preforms of a component carrier) and also for the component carriers. In a preferred embodiment, the separation component is shaped as a plate with two main surfaces, wherein one main surface is opposed to the other. Each surface may be termed “separation surface” and may be suitable for coupling a base structure. In this manner, on each of the two opposing separation surfaces, one base structure could be coupled. Alternatively, an electrically insulating layer (in a preferred embodiment a prepreg layer with a low Young modulus), may be arranged directly on the separation surfaces and the base structures are then placed onto the electrically insulating layers, respectively. In particular, the base structures may be pressing into the prepreg material. The separation component may be configured such that a feasible detachment of the (semi) finished component carriers is enabled. In an embodiment, the separation component may be configured as a detachment core. An example would be an electrically insulating material that is sandwiched between two copper foils. Hereby, an electrically insulating structure of the component carrier may be easily detachable from the copper foil. The separation component may be a detachment copper foil (DCF).
In the context of the present application, the term “redistribution structure” may refer to an additional structure comprising electrically conductive material (e.g. in the form of a metal layer and/or a conductive via) on an electronic component or a component carrier that makes I/O (inside/outside) pads of an integrated circuit available to other locations. When an electronic component, e.g. an integrated circuit, is manufactured, it usually has a set of I/O pads that are electrically connected (e.g. wire-bonded) to the pins of a package. A redistribution structure may be a structure of wiring on the chip that enables a simpler chip-to-chip, chip-to-component carrier, or component carrier-to-component carrier bonding. In an embodiment, the electric contacts (e.g. pad, terminal) at the component carrier side of the redistribution structure are smaller than the electric contacts at a main surface of the component carrier. The term “redistribution structure” may also include a redistribution layer (RDL) and/or a so-called “fan-out” structure. For example, the redistribution structure may comprise solder balls and/or copper pillars at the side (main surface), which is facing away from the embedded component, in order to be connectable to another, larger, entity. In an exemplary embodiment, the electric contacts of the embedded electronic component may be small in size and a redistribution structure is hence arranged below the electronic component (still within the component carrier). The redistribution structure may hereby be designed such that the small electric contacts of the electronic component are redistributed into terminals of a larger size, e.g. ball-shaped electric contacts (solder balls). In a most basic embodiment, the redistribution structure may be an interconnection via that connects a small electric contact with a larger electric contact. In particular, the small electric contact of an embedded component (in a component carrier) to a larger electric contact at a main surface of the component carrier. In another embodiment, the redistribution structure may comprise two interconnection vias and an electrically conductive layer between the two vias. Hereby, the vias may be arranged such that they are shifted in the horizontal axis with respect to each other. In this manner in can be taken into consideration that the larger electric contact needs more space than the small electric contact. Hence, by applying an electrically conductive layer between the side-shifted vias, the area for arranging the larger electric contacts may be spread.
In the context of the present application, the term “low Young modulus layer structure” may refer to any electrically insulating layer that comprises a Young modulus of less than 10 GPa. The Young modulus may be a mechanical property that measures the stiffness of a solid material. It defines the relationship between stress (force per unit area) and strain (proportional deformation) in a material in the linear elasticity regime of a uniaxial deformation. For example, copper comprises a high Young modulus of 117 GPa, and conventional electrically insulating material of a component carrier, e.g. glass-fiber enforced resin such as FR4, comprises an intermediate Young modulus of around 17 GPa. An example for a low Young modulus layer structure may be a specific prepreg material such as TD002 that comprises a Young modulus that may be much lower than that of FR4, e.g. 7 GPa.
In the context of the present application, the term “arranged in between” may refer to the circumstance that an electronic component is arranged directly in between a low Young modulus layer structure and a redistribution structure as defined above. In other words, the electronic component may be sandwiched between the low Young modulus layer structure and a redistribution structure. In an embodiment, a main surface of the electronic component may be flush with the low Young modulus layer structure. In another preferred embodiment, the electronic component is at least partially embedded in the low Young modulus layer structure. Furthermore, another main surface being opposed to the main surface of the electronic component, may by in direct contact with the redistribution structure. For example, an electric contact of the electronic component may be directly electrically contacted by a part of the redistribution structure, e.g. a via.
According to an exemplary embodiment, the invention is based on the idea that an electronic component may be embedded in a component carrier in a robust manner with respect to warpage and such that an efficient heat dissipation is achieved, when the component carrier is manufactured using a separation component. Conventionally, an electronic component may be embedded into a component carrier as described with regard to
With respect to heat dissipation, this may function much more reliably in a thin component carrier than in a component carrier structure with a thick core structure. Furthermore, with respect to the described component carrier, the thermal management may be highly improved by the specific architecture of an embedded electronic component being sandwiched between an electrically insulating layer structure with a low Young modulus and a (electrically conductive) redistribution structure that electrically connects a small electric contact of the embedded component to a large electric contact at the main surface of the component carrier. Thereby, without the need of additional efforts, the redistribution structure (made of an electrically conductive material such as copper) may function as a heat dissipation structure that efficiently guides the heat produced by the embedded component to the exterior of the component carrier (e.g. using an additional heat distribution layer).
In the following, further exemplary embodiments of the method and the component carrier will be explained.
According to an exemplary embodiment, the method further comprises i) forming, in particular laminating, a first electrically insulating layer on the first separation surface before coupling the first base structure with the first separation surface, and afterwards attaching the first base structure on top of the first electrically insulating layer, and ii) forming, in particular laminating, a second electrically insulating layer on the second separation surface before coupling the second base structure with the second separation surface, and afterwards attaching the second base structure on top of the second electrically insulating layer. This may provide the advantage that the base structures can be attached to the separation component in a flexible and robust manner.
The electrically insulating layers may be laminated onto the first and the second separation surface of the separation component. In a preferred embodiment, the electrically insulating layers have a larger area size than the separation component. Thereby, for example also the sidewalls of the separation component may be covered. In this manner, the separation component may be more robust and the electrically insulating layers do not tend to “fall off” anymore. In an embodiment, the electrically insulating layers may be formed of a deformable material so that the base structures may be pressed into it and thereby may be attached to the separation component in an efficient manner.
According to a further exemplary embodiment, the first electrically insulating layer and the second electrically insulating layer comprise or consist of prepreg material. This may provide the advantage that the base structures can be pressed into a deformable material and are thereby efficiently hold in place.
Prepreg material or “pre-impregnated fibers” may be a thermoset polymer matrix material, such as epoxy, or a thermoplastic resin may be already present. The fibers often take the form of a weave and the matrix may be used to bond them together and/or to other components during a manufacturing process. Prepreg may be a printed circuit board material such as FR4 or FR5 in an uncured state. For example, glass fibers may be embedded in an epoxy matrix, however, the material is still uncured or at least not fully cured so that it is deformable to some extent. Being at least partially deformable, it may be possible to press and/or pierce a physical structure into it. For example, an electrically conductive pillar structure of a base structure or an electronic component may be pressed at least partially into the prepreg material. Prepreg may be brought into a cured state by applying high temperature and/or pressure. The cured material may not be deformable anymore.
According to a further exemplary embodiment, the first electrically insulating layer and the second electrically insulating layer are formed of a low Young modulus material, e.g. a material having a Young modulus of less than 10 GPa, particularly a Young modulus of less than 2 GPa, more particularly a Young modulus of less than 0.5 GPa. This may provide the advantage that stress is absorbed and crack formation is reduced.
According to a further exemplary embodiment, placing the first electronic component in the first cavity is done after coupling the first base structure with the first separation surface, and placing the second electronic component in the second cavity is done after coupling the second base structure with the second separation surface. This may provide the advantage that the described method is applicable in a flexible manner, while still being robust.
The base structure may comprise an electrically insulating layer structure and electrically conductive structures. These first and second base structures may be placed onto the separation sides of a separation component. Hereby, a respective cavity may be provided in the electrically insulating layer structure, yet without an electronic component. The separation component may comprise electrically insulating layer (e.g. prepreg material) as described above or merely adhesive material layers (e.g. of FR4). The base structures may be pressed into the electrically insulating layers or may be merely adhered to the respective adhesive material layers. Then, the first electronic component may be placed in the first cavity (and adhered to the adhesive material) and the second electronic component may be placed in the second cavity. Afterwards, a lamination step (see description below) may be applied in order to embed the first electronic component and the second electronic component with the electrically insulating material of at least one further electrically insulating layer structure. When the base structures have been adhered to the adhesive material, they may be later-on detached from the separation component in an efficient residue-free manner (optionally using thermal treatment). Optionally further layers of electrically conductive and/or electrically insulating material may be applied before detaching the semi-finished component carriers from the separation component. Finally, a solder mask may be applied to the component carrier/base structure.
According to a further exemplary embodiment, i) placing the first electronic component in the first cavity is done before coupling the first base structure with the first separation surface, and ii) placing the second electronic component in the second cavity is done before coupling the second base structure with the second separation surface. The method further comprising: iii) attaching the first base structure on top of the first electrically insulating layer such that a main surface of the first electronic component is directly attached to the first electrically insulating layer, and iv) attaching the second base structure on top of the second electrically insulating layer such that a main surface of the second electronic component is directly attached to the second electrically insulating layer. This may provide the advantage that the placing of the electronic component can be directly integrated into the production process at the desired position.
In an embodiment, the electronic component may be placed in the cavity, when the base structure is already coupled with the separation component. In a further embodiment, the base structure may be coupled with the separation component and the cavity is still accessible. In this manner, the electronic component may be placed into the base structure while the base structure is already coupled to the separation component. In another embodiment, the electronic component may be placed into the cavity (e.g. on a temporary carrier) and is then already at the base structure, when the base structure is coupled with the separation component. In a preferred embodiment, the base structure and the electronic component (already in the cavity of the base structure) are pressed into a deformable/flexible material on top of the separation component, e.g. an additional electrically insulating layer. In this manner, the base structure and the electronic component can be attached in a robust manner. Hence, the electronic components can be directly integrated into the manufacturing and build-up process.
According to a further exemplary embodiment, the method further comprises: at least partially embedding the first electronic component in the first cavity of the first base structure before attaching the first base structure on top of the first electrically insulating layer (and/or coupling the first base structure with the separation component) and/or at least partially embedding the second electronic component in the second cavity of the second base structure before attaching the second base structure on top of the second electrically insulating layer (and/or coupling the second base structure with the separation component). This may provide the advantage that a robust base structure with an at least partially connected electronic component is attached to the separation component in a stable manner.
The electronic component may be at least partially embedded with an electrically insulating material, e.g. prepreg, or fully embedded before the base structure is coupled to the separation component. The prepreg may be cured after embedding the electronic component or during a later process step. In this manner, the base structure may be more stable and robust and the electronic component may be more stabilized and does not fall off easily. Furthermore, the electronic component may be embedded more efficiently in this manner, than by merely being pressed into a prepreg layer of the separation component. Additionally, the base structure may be pressed into the electrically insulating layer of the separation component such that an un-embedded rest of the base structure/electronic component (not embedded by the electrically insulating material) becomes embedded by pressing the base structure into the (uncured) electrically insulating layer.
According to a further exemplary embodiment, the method further comprising: i) pressing the first electronic component in the first electrically insulating layer so that the first electronic component becomes at least partially embedded by the first electrically insulating layer, and/or ii) pressing the second electronic component in the second electrically insulating layer so that the second electronic component becomes at least partially embedded by the second electrically insulating layer. This may provide the advantage that the electronic component can be fixed and embedded in a fast and efficient manner.
In order to connect the electronic component with the base structure, thereby forming the component carrier, the electronic component may at least partially be embedded with electrically insulating material. Embedding an electronic component may provide many advantages, such as protection against stress or other physical impacts, and a thin structure of the whole component carrier. In the described manner, two tasks may be fulfilled at the same time: i) the electronic component is pressed into the electrically insulating layer (which is at least partially deformable and flexible) and thereby fixed at its position in the cavity of the base structure, and ii) the electronic component is at the same time embedded with the material of the electrically insulating layer. In a preferred embodiment, the electrically insulating layer may hereby be an elastic uncured prepreg material. In a following step, a mixture of high temperature and pressure may be applied in order to cure the prepreg material. This may provide a tight connection between the base structure, the electronic component and the electrically insulating layer.
According to a further exemplary embodiment, the method further comprising: i) laminating a first further electrically insulating layer structure on the first base structure or the first component carrier, in particular such that the first electronic component is at least partially embedded with the first further electrically insulating layer structure, and/or ii) laminating a second further electrically insulating layer structure on the second base structure or the second component carrier, in particular such that the second electronic component is at least partially embedded with the second further electrically insulating layer structure.
According to a further exemplary embodiment, the method further comprising: i) forming a first electrically conductive interconnection, in particular a first via, more in particular through the first further electrically insulating layer structure, in order to electrically contact a first electric contact of the first electronic component, and/or ii) forming a second electrically conductive interconnection, in particular a second via, more in particular through the second further electrically insulating layer structure, in order to electrically contact a first electric contact of the second electronic component. This may provide the advantage that a layer built-up can be performed in an efficient manner using established technologies.
For building-up the layer stack of the component carrier, several layers of electrically insulating material may be laminated on top of the electronic component layer. In order to electrically connect the embedded electronic component, electrically conductive interconnection paths may be established. The material of the further electrically insulating layer structures may hereby be used to at least partially embed the electronic component. In another embodiment, the electronic component is at least partially embedded by material of the electrically insulating layer (described above) and is then further embedded by material of the further electrically insulating layer structure. In an exemplary embodiment, the further electrically insulating layer structure may comprise PID and/or ABF (Ajinomoto build-up film). For layer build-up known technology such as standard HDI (high density integration) SAP (semi-additive process) or mSAP (modified semi-additive process) may be used.
An interconnection path may be an electrically conductive via, at least partially filled with an electrically conductive material such as a metal, e.g. copper. Furthermore, metal like copper comprises a high thermal conductivity such that the heat produced by the electronic component may be directly dissipated through the interconnection path. Besides vias, the interconnection path may also comprise metal layers that electrically (and thermally) connect vias with each other in the horizontal plane.
The term “via” may particularly denote a vertical interconnection access being an electrical connection between layers in a component carrier (e.g. a printed circuit board) that goes through the plane of one or more adjacent layers. The term via may include through-hole vias, buried vias, and blind vias. A blind via may be a via that is not completely drilled through an electrically insulating layer, but is merely formed into the electrically insulating layer. For example, the blind via may extend down to an embedded component. In another context, the term blind via may refer to a via in a component carrier which comprises a plurality of layers, wherein the blind via extends through one or several, but not all, of the plurality of layers of the component carrier. For example, a via may connect an electrically conductive layer on top of an electrically insulating layer, through said electrically insulating layer, to another electrically conductive layer below the electrically insulating layer. There are a variety of techniques available for manufacturing a via and/or a photo via in a component carrier. For example, mechanical drilling or laser drilling using e.g. CO2 laser, Excimer laser, Nd-YAG laser, UV laser, and a photo via using PID material.
According to a further exemplary embodiment, the method further comprising: i) forming a second electric contact, in particular formed as a solder ball, on a main surface of the first component carrier, and electrically connecting the second electric contact through the first electrically conductive interconnection with the first electric contact of the first electronic component, wherein the second electric contact is larger than the first electric contact of the first electronic component such that a first redistribution structure is provided, and/or ii) forming a further second electric contact, in particular formed as a solder ball, on a further main surface of the second component carrier, and electrically connecting the further second electric contact through the second electrically conductive interconnection with the second electric contact of the second electronic component, wherein the further second electric contact is larger than the further second electric contact of the second electronic component such that a second redistribution structure is provided. This may provide the advantage, that the embedded electronic component can be electrically connected in a very flexible manner. A redistribution structure has already been described above in detail. Such a structure enables an efficient electrical connection between a small electric contact (pad) to a large electric contact (e.g. solder ball).
According to a further exemplary embodiment, the first electronic component is sandwiched between the first electrically insulating layer, in particular at least partially embedded in the first electrically insulating layer, and the first redistribution structure, and/or the second electronic component is sandwiched between the second electrically insulating layer, in particular at least partially embedded in the second electrically insulating layer, and the second redistribution structure. This may provide the advantage that at the same time, i) an efficient redistribution structure is provided, and ii) a component carrier (with an embedded electronic component) is manufactured in a very efficient manner.
The efficient manner of manufacturing the component carrier, by pressing a base structure into an electrically insulating layer, has already been described above. Due to the use of the separation component and two base structures at the same time, a thick structure may be provided such that also coreless structures may be manufactured without warpage problems. This process may further be advantageously combined with the manufacturing of a redistribution structure that efficiently electrically connects the embedded electronic component to the main surface of the component carrier.
According to a further exemplary embodiment, separating comprises: i) detaching the first component carrier including the first electrically insulating layer from the separation component, and/or ii) detaching the second component carrier including the second electrically insulating layer from the separation component. This may provide the advantage, that the component carriers can be detached from the separation component in an efficient manner. At the same time, the electrically insulating layers become advantageously parts of the component carriers.
Electrically insulating material such as resin may not have good adhesive properties with respect to a copper foil that may be on the separation surface of the separation component. Thus, an easy detachment process is achieved.
According to a further exemplary embodiment, attaching the first base structure on top of the first electrically insulating layer further comprises: i) piercing at least one first electrically conductive pillar structure of the first base structure into the first electrically insulating layer, and/or attaching the second base structure on top of the second electrically insulating layer further comprises: ii) piercing at least one second electrically conductive pillar structure of the second base structure into the second electrically insulating layer. This may provide the advantage, that the base structures are attached to the electrically insulating layers in a very robust manner.
Electrically conductive layer structures (e.g. vias) of the base structures may be enlarged in order to form pillar structures. The pillar structures may be long and extend beyond the surface of the base structure. In this manner, when the base structures are placed onto the electrically insulating layers, the pillar structures are pierced into the electrically insulating layers, which are preferably made of a deformable material.
According to a further exemplary embodiment, the separation component is fully surrounded by material of the first electrically insulating layer and the second electrically insulating layer. This may provide the advantage that an undesired detachment of separation component and electrically insulating layer is prevented.
The separation surfaces of the separation component may comprise a metal layer, e.g. a copper foil. The electrically insulating layer may consist of resin, but also other insulating materials are suitable. By completely surrounding the separation component, the electrically insulating layers may be attached to the separation surface in an especially robust manner to prevent undesired detachment from the separation surfaces.
According to a further exemplary embodiment, the separation component is a detachment core, in particular a (electrically insulating) core structure sandwiched between two detach copper foils. This may provide the advantage, that a very cost-efficient and established component can be directly applied. The separation component may be a so-called detachable copper foil (DCF) which may be a mass product that is easily available in large quantities and may even be reused after the manufacturing process.
In another embodiment, the separation component may comprise a dummy core sandwiched between two dummy insulator layers which are respectively covered with a copper foil. The dummy core may optionally comprise an electrically conductive structure such as a through-via. The separation surface may comprise two copper layers, adhesive material layers, and/or additional release layers.
According to a further exemplary embodiment, the first component carrier and/or the second component carrier is a coreless component carrier. Thereby, an advantageous component carrier can be efficiently produced as a very thin structure and, in particular, reducing or preventing known problems such as warpage.
A coreless component carrier may be significantly thinner than a component carrier with a massive core structure. Hence, the coreless component carrier may be applied in a more flexible manner, e.g. when being integrated into an electronic assembly. Furthermore, a thin component carrier may dissipate heat in a more efficient manner. As has already been described above, a coreless component carrier is, due to its thin design, prone to bending/warpage during a manufacturing process on the panel level. However, two coreless component carrier, each on a separation surface of a separation component, may represent a stable and robust structure that is improved with respect to the previous issues.
According to a further exemplary embodiment, the first electronic component is placed on a first tape of the first base structure, wherein the method further comprises: removing the first tape after coupling the first base structure with the first separation surface; and/or the second electronic component is placed on a second tape of the second base structure, wherein the method further comprises: removing the second tape after coupling the second base structure with the second separation surface. This may provide the advantage that established technologies can be directly integrated into the production process. The temporary carrier may hold the electronic component in the cavity of the base structure in place. At a later step during the manufacturing process, when the electronic component is already fixed (e.g. embedded in electrically insulating material, then the temporary carrier may be detached.
According to a further exemplary embodiment, the component carrier further comprises a heat distribution layer formed on the low Young modulus layer and facing the main surface of the electronic component. In particular, the heat distribution layer is electrically and thermally connected with the electrically conductive interconnection such that the heat distribution layer and the electrically conductive interconnection at least partially surround the cavity. This may provide the advantage that an efficient heat dissipation for the embedded electronic component is provided.
The electronic component is embedded in an electrically insulating material, typically a resin, which may not comprise feasible thermal conductivity properties. As a consequence, the heat produced by the electronic component cannot be efficiently transported and the electronic component may overheat. This problem may be solved by a heat distribution layer (e.g. made of a metal such as copper or another material with feasible thermal conductivity) formed on the electrically insulating layer. Hereby, the heat distribution layer may be formed on the main surface of the component carrier which is opposite to the main surface that comprises the second electric contacts. In other words, the heat distribution layer may be attached at the main surface of the component carrier which main surface is opposed to the other main surface, where the redistribution structure is formed. The heat distribution layer thus may face the main surface of the electric component which does not comprise the first electric contacts. The heat from the electronic component may be guided through vias (of the electrically conductive interconnection) to the heat distribution layer, wherein the heat distribution layer and the vias are electrically and thermally connected with each other. Hereby, the vias may surround the cavity in which the electronic component has been placed. This may enable an especially efficient heat dissipation. Furthermore, the electric interconnection may connect the heat distribution layer with the redistribution structure. As electrically conductive material such as copper generally comprises feasible thermally conductivity, already existing electrical connections may at the same time be used as efficient heat dissipation structures.
According to a further exemplary embodiment, the whole structure of two component carriers and a separation component (i.e. the semi-finished product) may be around 400 μm thick. According to another embodiment, a single build-up layer (i.e. one of the component carriers) may have a thickness below 70 μm. In a further embodiment, each of the two component carriers may have a thickness below 70 μm.
According to an exemplary embodiment, the electronic component can be selected from a group consisting of an electrically non-conductive inlay, an electrically conductive inlay (such as a metal inlay, preferably comprising copper or aluminum), a heat transfer unit (for example a heat pipe), a light guiding element (for example an optical waveguide or a light conductor connection), a die, an electronic component, or combinations thereof. For example, the component can be an active electronic component, a passive electronic component, an electronic chip, a storage device (for instance a DRAM or another data memory), a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface element, a light emitting diode, a photocoupler, a voltage converter (for example 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 microelectromechanical system (MEMS), a microprocessor, a capacitor, a resistor, an inductance, a battery, a switch, a camera, a logic chip, a light guide, and an energy harvesting unit. However, other components may be embedded in or surface mounted on the component carrier. For example, a magnetic element can be used as a component. Such a magnetic element may be a permanent magnetic element (such as a ferromagnetic element, an antiferromagnetic element or a ferromagnetic element, for instance a ferrite coupling structure) or may be a paramagnetic element. However, the component may also be a substrate, an interposer or a further component carrier, for example in a board-in-board configuration. Moreover, also other components, in particular those which generate and emit electromagnetic radiation and/or are sensitive with regard to electromagnetic radiation propagating from an environment, may be used as component.
In an embodiment, the at least one electrically insulating (layer) structure comprises at least one of the group consisting of resin (such as reinforced or non-reinforced resins, for instance epoxy resin or Bismaleimide-Triazine resin, cyanate ester, polyphenylene derivate, glass (in particular glass fibers, multi-layer glass, glass-like materials), prepreg material (such as FR-4 or FR-5), polyimide, polyamide, liquid crystal polymer (LCP), epoxy-based Build-Up Film, polytetrafluoroethylene (Teflon), a ceramic, and a metal oxide. Reinforcing materials such as webs, fibers or spheres, for example made of glass (multilayer glass) may be used as well. Although prepreg particularly FR4 are usually preferred for rigid PCBs, other materials in particular epoxy-based Build-Up Film for substrates for substrates may be used as well. For high frequency applications, high-frequency materials such as polytetrafluoroethylene, liquid crystal polymer and/or cyanate ester resins, low temperature cofired ceramics (LTCC) or other low, very low or ultra-low DK-materials may be implemented in the component carrier as electrically insulating layer structure.
In an embodiment, the component carrier comprises a stack of at least one electrically insulating layer structure and at least one electrically conductive layer structure. For example, the component carrier may be a laminate of the mentioned electrically insulating layer structure(s) and electrically conductive layer structure(s), in particular formed by applying mechanical pressure and/or thermal energy. The mentioned stack may provide a plate-shaped component carrier capable of providing a large mounting surface for further components and being nevertheless very thin and compact. The term “layer structure” may particularly denote a continuous layer, a patterned layer or a plurality of non-consecutive islands within a common plane.
In an embodiment, the component carrier is shaped as a plate. This contributes to the compact design, wherein the component carrier nevertheless provides a large basis for mounting components thereon. Furthermore, in particular a naked die as example for an embedded electronic component, can be conveniently embedded, thanks to its small thickness, into a thin plate such as a printed circuit board.
In an embodiment, the component carrier is configured as one of the group consisting of a printed circuit board, a substrate (in particular an IC substrate), and an interposer.
In the context of the present application, the term “printed circuit board” (PCB) may particularly denote a plate-shaped component carrier which is formed by laminating several electrically conductive layer structures with several electrically insulating layer structures, for instance by applying pressure and/or by the supply of thermal energy. As preferred materials for PCB technology, the electrically conductive layer structures are made of copper, whereas the electrically insulating layer structures may comprise resin and/or glass fibers, so-called prepreg such as FR4 material. The various electrically conductive layer structures may be connected to one another in a desired way by forming through-holes through the laminate, for instance by laser drilling or mechanical drilling, and by filling them with electrically conductive material (in particular copper), thereby forming vias as through-hole connections. Apart from one or more components which may be embedded in a printed circuit board, a printed circuit board is usually configured for accommodating one or more components on one or both opposing surfaces of the plate-shaped printed circuit board. They may be connected to the respective main surface by soldering. A dielectric part of a PCB may be composed of resin with reinforcing particles (such as reinforcing spheres, in particular glass spheres).
In the context of the present application, the term “substrate” may particularly denote a small component carrier having substantially the same size as a component (in particular an electronic component) to be mounted thereon. More specifically, a substrate can be understood as a carrier for electrical connections or electrical networks as well as component carrier comparable to a printed circuit board (PCB), however with a considerably higher density of laterally and/or vertically arranged connections. Lateral connections are for example conductive paths, whereas vertical connections may be for example drill holes. These lateral and/or vertical connections are arranged within the substrate and can be used to provide electrical and/or mechanical connections of housed components or unhoused components (such as bare dies), particularly of IC chips, with a printed circuit board or intermediate printed circuit board. Thus, the term “substrate” also includes “IC substrates”. A dielectric part of a substrate may be composed of resin with reinforcing particles (such as reinforcing spheres, in particular glass spheres). Furthermore, the component carrier may be configured as a substrate-like-printed circuit board (SLP).
The substrate or interposer may consist of at least a layer of glass, Silicon (Si) or a photo-imageable or dry-etchable organic material like epoxy-based Build-Up films or polymer compounds like Polyimide, Polybenzoxazole, or Benzocyclobutene.
In an embodiment, 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. Although copper is usually preferred, other materials or coated versions thereof are possible as well, in particular coated with supra-conductive material such as graphene.
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.
The illustrations in the drawings are schematically presented. In different drawings, similar or identical elements are provided with the same reference signs.
Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the invention have been developed.
According to an exemplary embodiment of the invention, the following steps are included in the manufacturing process: i) providing a low cost detach core (DCF) sandwiched between two prepreg (PPG) layers, ii) performing a lay-up using two base structures (comprising each an electronic component on a temporary carrier), iii) hot pressing (laminating) and trimming (cutting edges), iv) de-taping the temporary carrier and performing a first step of layer build-up, v) performing a second step of layer build-up, vi) providing surface finish and solder resist, vii) again trimming and then detaching the component carriers from the DCF, and viii) attaching a heat distribution layer at the PPG layer and provide solder balls to the redistribution structure.
According to an exemplary embodiment of the invention, a fan-out wafer level packaging (FOWLP) is one of the latest packaging trends in microelectronics. It has a high potential for significant package miniaturization concerning package volume but also its thickness. Technological core of FOWLP is the formation of a reconfigured molded wafer combined with a thin film redistribution layer to yield an SMD-compatible package. Main advantages of FOWLP are the substrate-less package, low thermal resistance, improved RF performance due to shorter interconnects together with direct IC connection by thin film metallization instead of wire bonds or flip chip bumps and lower parasitic effects. Especially the inductance of FOWLP is much lower compared to FC-BGA packages. In addition, the redistribution layer can also provide embedded passives as well as antenna structures using a multi-layer structure. It can be used for multi-chip packages for system-in-package (SiP) and heterogeneous integration. For higher productivity and resulting lower cost, larger mold embedding form factors are forecast for the near future. Besides increasing wafer diameter, an alternative option would be moving to panel sizes leading to fan-out panel level packaging (FOPLP). Panel sizes could range from 18″×24″ (a PCB manufacturing standard) to even larger sizes. However, a FO-PLP (fan-out panel level packaging) substrate embedding the functional chip needs an efficient thermal management to facilitate smooth chip operation. An object of the invention is hence to provide a high yield production method for single side build FO-PLP products with thin core (i.e. component carriers) using DCF (detach copper foil) as a separation component. The FO-PLP products further have an enhanced heat dissipation capacity by surrounding the cavity with the embedded component with heat spread metal (e.g. an electrically conductive interconnection) and a heat dissipation layer (e.g. a heat distribution layer) on the top layer. The heat spread metal and the heat dissipation layer are hereby interconnected by one or more vias.
According to an exemplary embodiment of the invention, in particular when placing the electronic components in the cavities after the base structures have been coupled with the separation component, the following advantages may be provided: i) solving the tape (temporary carrier) twisty issue and make sure it is flat during front side encapsulation, especially for a large component-package ratio, ii) prevent the movement or deformation during lamination, iii) flexible application and more efficiency on first lamination or hot press; two panels (component carriers) proceed at one time is possible, iv) warpage performance becomes better during and after first lamination, v) applying the thermal released adhesive may help to reduce the risk of leaving residuals, and vi) making it more feasible to remove the temporary adhesive layer or carrier (temporary carrier or separation component) with a thermal release adhesive.
According to an exemplary embodiment of the invention, the following steps are performed: i) laminating a double side adhesive (adhesive material) on two sides of a separation component (could be a FR4 material with 400 μm thickness), ii) attaching the base structures with completed cavity and pattern on two sides of the separation component, iii) proceeding the pick & place process for both cores on two sides, iv) proceeding the first lamination or hot press or both cores on two sides at the same time, v) removing the separation component by additional thermal treatment or merely removing it after a lamination step or a hot press process (based on the adhesive selection and process flow requirements), and vi) continuing the further processes as normal CCE (Center Core Embedded) process, laminating or hot pressing on the back side or both sides.
In the following description of exemplary embodiments, generally a double-side build-up (from both separation surfaces of the separation component) is described. However, each of these processes can also be performed with a single-side build-up, i.e. using just one separation surface of the separation component to build just one component carrier. In this case, it may be reasonably sufficient if the separation component has only one separation surface on that surface which is used for realizing the build-up.
In an embodiment (not shown in this Figure), the first electronic component 115 is at least partially embedded (using an electrically insulating material) in the first cavity 111 of the first base structure 110 before attaching the first base structure 110 on top of the first electrically insulating layer 130 and/or the second electronic component 125 is at least partially embedded (using an electrically insulating material) in the second cavity 121 of the second base structure 120 before attaching the second base structure 121 on top of the second electrically insulating layer 140.
It should be noted that the term “comprising” does not exclude other elements or steps and the use of the article “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201811384918.5 | Nov 2018 | CN | national |
