The semiconductor industry has experienced rapid growth due to ongoing improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). For the most part, improvement in integration density has resulted from iterative reduction of minimum feature size, which allows more components to be integrated into a given area. As the demand for shrinking electronic devices has grown, a need for smaller and more creative packaging techniques of semiconductor dies has emerged. An example of such packaging systems is Package-on-Package (PoP) technology. In a PoP device, a top semiconductor package is stacked on top of a bottom semiconductor package to provide a high level of integration and component density. PoP technology generally enables production of semiconductor devices with enhanced functionalities and small footprints on a printed circuit board (PCB).
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
In accordance with some embodiments, one or more integrated circuit dies are electrically connected by a fan-out structure (e.g., a redistribution structure, an interposer, a local silicon interconnect (LSI), or the like), and the integrated circuit dies may be encapsulated for further packaging with other package components (e.g., a package substrate or the like). One or more openings may be formed in the molding compound and/or the fan-out structure. The inclusion of the openings may provide the following, non-limiting advantages. For example, the opening may facilitate thermal dissipation of heat away from the semiconductor dies through the openings. As another example, the openings may facilitate the insertion of one or more advantageous components, such as a thermal dissipation feature, electromagnetic interference (EMI) shields, or the like. Further, the openings may facilitate the insertion of structural support elements (e.g., braces or the like) in the package. As a result, improved package performance and/or manufacturing ease may be achieved.
The integrated circuit die 50 may be formed in a wafer, which may include different device regions that are singulated in subsequent steps to form a plurality of integrated circuit dies. The integrated circuit die 50 may be processed according to applicable manufacturing processes to form integrated circuits. For example, the integrated circuit die 50 includes a semiconductor substrate 52, such as silicon, doped or undoped, or an active layer of a semiconductor-on-insulator (SOI) substrate. The semiconductor substrate 52 may include other semiconductor materials, such as germanium; a compound semiconductor including silicon carbide, gallium arsenic, gallium phosphide, indium phosphide, indium arsenide, and/or indium antimonide; an alloy semiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and/or GaInAsP; or combinations thereof. Other substrates, such as multi-layered or gradient substrates, may also be used. The semiconductor substrate 52 has an active surface (e.g., the surface facing upwards in
Devices (represented by a transistor) 54 may be formed at the front surface of the semiconductor substrate 52. The devices 54 may be active devices (e.g., transistors, diodes, etc.), capacitors, resistors, etc. An inter-layer dielectric (ILD) 56 is over the front surface of the semiconductor substrate 52. The ILD 56 surrounds and may cover the devices 54. The ILD 56 may include one or more dielectric layers formed of materials such as Phospho-Silicate Glass (PSG), Boro-Silicate Glass (BSG), Boron-Doped Phospho-Silicate Glass (BPSG), undoped Silicate Glass (USG), or the like.
Conductive plugs 58 extend through the ILD 56 to electrically and physically couple the devices 54. For example, when the devices 54 are transistors, the conductive plugs 58 may couple the gates and source/drain regions of the transistors. Source/drain region(s) may refer to a source or a drain, individually or collectively dependent upon the context. The conductive plugs 58 may be formed of tungsten, cobalt, nickel, copper, silver, gold, aluminum, the like, or combinations thereof. An interconnect structure 60 is over the ILD 56 and conductive plugs 58. The interconnect structure 60 interconnects the devices 54 to form an integrated circuit. The interconnect structure 60 may be formed by, for example, metallization patterns in dielectric layers on the ILD 56. The metallization patterns include metal lines and vias formed in one or more low-k dielectric layers. The metallization patterns of the interconnect structure 60 are electrically coupled to the devices 54 by the conductive plugs 58.
The integrated circuit die 50 further includes pads 62, such as aluminum pads, to which external connections are made. The pads 62 are on the active side of the integrated circuit die 50, such as in and/or on the interconnect structure 60. One or more passivation films 64 are on the integrated circuit die 50, such as on portions of the interconnect structure 60 and pads 62. Openings extend through the passivation films 64 to the pads 62. Die connectors 66, such as conductive pillars (for example, formed of a metal such as copper), extend through the openings in the passivation films 64 and are physically and electrically coupled to respective ones of the pads 62. The die connectors 66 may be formed by, for example, plating, or the like. The die connectors 66 electrically couple the respective integrated circuits of the integrated circuit die 50.
Optionally, solder regions (e.g., solder balls or solder bumps) may be disposed on the pads 62. The solder balls may be used to perform chip probe (CP) testing on the integrated circuit die 50. CP testing may be performed on the integrated circuit die 50 to ascertain whether the integrated circuit die 50 is a known good die (KGD). Thus, only integrated circuit dies 50, which are KGDs, undergo subsequent processing and are packaged, and dies, which fail the CP testing, are not packaged. After testing, the solder regions may be removed in subsequent processing steps.
A dielectric layer 68 may (or may not) be on the active side of the integrated circuit die 50, such as on the passivation films 64 and the die connectors 66. The dielectric layer 68 laterally encapsulates the die connectors 66, and the dielectric layer 68 is laterally coterminous with the integrated circuit die 50. Initially, the dielectric layer 68 may bury the die connectors 66, such that the topmost surface of the dielectric layer 68 is above the topmost surfaces of the die connectors 66. In some embodiments where solder regions are disposed on the die connectors 66, the dielectric layer 68 may bury the solder regions as well. Alternatively, the solder regions may be removed prior to forming the dielectric layer 68.
The dielectric layer 68 may be a polymer such as PBO, polyimide, BCB, or the like; a nitride such as silicon nitride or the like; an oxide such as silicon oxide, PSG, BSG, BPSG, or the like; the like, or a combination thereof. The dielectric layer 68 may be formed, for example, by spin coating, lamination, chemical vapor deposition (CVD), or the like. In some embodiments, the die connectors 66 are exposed through the dielectric layer 68 during formation of the integrated circuit die 50. In some embodiments, the die connectors 66 remain buried and are exposed during a subsequent process for packaging the integrated circuit die 50. Exposing the die connectors 66 may remove any solder regions that may be present on the die connectors 66.
In some embodiments, the integrated circuit die 50 is a stacked device that includes multiple semiconductor substrates 52. For example, the integrated circuit die 50 may be a memory device such as a hybrid memory cube (HMC) module, a high bandwidth memory (HBM) module, or the like that includes multiple memory dies. In such embodiments, the integrated circuit die 50 includes multiple semiconductor substrates 52 interconnected by through-substrate vias (TSVs). Each of the semiconductor substrates 52 may (or may not) have an interconnect structure 60.
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The release layer 104 may be formed of a polymer-based material, which may be removed along with the carrier substrate 102 from the overlying structures that will be formed in subsequent steps. In some embodiments, the release layer 104 is an epoxy-based thermal-release material, which loses its adhesive property when heated, such as a light-to-heat-conversion (LTHC) release coating. In other embodiments, the release layer 104 may be an ultra-violet (UV) glue, which loses its adhesive property when exposed to UV lights. The release layer 104 may be dispensed as a liquid and cured, may be a laminate film laminated onto the carrier substrate 102, or may be the like. The top surface of the release layer 104 may be leveled and may have a high degree of planarity.
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The dielectric layer 108 may be formed on the release layer 104. The bottom surface of the dielectric layer 108 may be in contact with the top surface of the release layer 104. In some embodiments, the dielectric layer 108 is formed of a polymer, such as polybenzoxazole (PBO), polyimide, benzocyclobutene (BCB), or the like. In other embodiments, the dielectric layer 108 is formed of a nitride such as silicon nitride; an oxide such as silicon oxide, phosphosilicate glass (PSG), borosilicate glass (BSG), boron-doped phosphosilicate glass (BPSG), or the like; or the like. The dielectric layer 108 may be formed by any acceptable deposition process, such as spin coating, CVD, laminating, the like, or a combination thereof.
The metallization pattern 110 may be formed on the dielectric layer 108. As an example to form metallization pattern 110, a seed layer is formed over the dielectric layer 108. In some embodiments, the seed layer is a metal layer, which may be a single layer or a composite layer comprising a plurality of sub-layers formed of different materials. In some embodiments, the seed layer comprises a titanium layer and a copper layer over the titanium layer. The seed layer may be formed using, for example, physical vapor deposition (PVD) or the like. A photoresist (not shown) is then formed and patterned on the seed layer. The photoresist may be formed by spin coating or the like and may be exposed to light for patterning. The pattern of the photoresist corresponds to the metallization pattern 110. The patterning forms openings through the photoresist to expose the seed layer. A conductive material is formed in the openings of the photoresist and on the exposed portions of the seed layer. The conductive material may be formed by plating, such as electroplating or electroless plating, or the like. The conductive material may comprise a metal, like copper, titanium, tungsten, aluminum, or the like. Then, the photoresist and portions of the seed layer on which the conductive material is not formed are removed. The photoresist may be removed by an acceptable ashing or stripping process, such as using an oxygen plasma or the like. Once the photoresist is removed, exposed portions of the seed layer are removed, such as by using an acceptable etching process, such as by wet or dry etching. The remaining portions of the seed layer and conductive material form the metallization pattern 110.
The dielectric layer 112 may be formed on the metallization pattern 110 and the dielectric layer 108. In some embodiments, the dielectric layer 112 is formed of a polymer, which may be a photo-sensitive material such as PBO, polyimide, BCB, or the like, that may be patterned using a lithography mask. In other embodiments, the dielectric layer 112 is formed of a nitride such as silicon nitride; an oxide such as silicon oxide, PSG, BSG, BPSG; or the like. The dielectric layer 112 may be formed by spin coating, lamination, CVD, the like, or a combination thereof. The dielectric layer 112 is then patterned to form openings 114 exposing portions of the metallization pattern 110. The patterning may be formed by an acceptable process, such as by exposing the dielectric layer 112 to light when the dielectric layer 112 is a photo-sensitive material or by etching using, for example, an anisotropic etch. If the dielectric layer 112 is a photo-sensitive material, the dielectric layer 112 can be developed after the exposure.
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The adhesive 118 is on back-sides of the integrated circuit dies 50 and adheres the integrated circuit dies 50 to the back-side redistribution structure 106, such as to the dielectric layer 112. The adhesive 118 may be any suitable adhesive, epoxy, die attach film (DAF), or the like. The adhesive 118 may be applied to back-sides of the integrated circuit dies 50, may be applied over the surface of the carrier substrate 102 if no back-side redistribution structure 106 is utilized, or may be applied to an upper surface of the back-side redistribution structure 106 if applicable. For example, the adhesive 118 may be applied to the back-sides of the integrated circuit dies 50 before singulating to separate the integrated circuit dies 50.
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The metallization pattern 126 is then formed. The metallization pattern 126 includes conductive elements extending along the major surface of the dielectric layer 124 and extending through the dielectric layer 124 to physically and electrically couple to the through vias 116 and the integrated circuit dies 50. As an example to form the metallization pattern 126, a seed layer is formed over the dielectric layer 124 and in the openings extending through the dielectric layer 124. In some embodiments, the seed layer is a metal layer, which may be a single layer or a composite layer comprising a plurality of sub-layers formed of different materials. In some embodiments, the seed layer comprises a titanium layer and a copper layer over the titanium layer. The seed layer may be formed using, for example, PVD or the like. A photoresist is then formed and patterned on the seed layer. The photoresist may be formed by spin coating or the like and may be exposed to light for patterning. The pattern of the photoresist corresponds to the metallization pattern 126. The patterning forms openings through the photoresist to expose the seed layer. A conductive material is then formed in the openings of the photoresist and on the exposed portions of the seed layer. The conductive material may be formed by plating, such as electroplating or electroless plating, or the like. The conductive material may comprise a metal, like copper, titanium, tungsten, aluminum, or the like. The combination of the conductive material and underlying portions of the seed layer form the metallization pattern 126. The photoresist and portions of the seed layer on which the conductive material is not formed are removed. The photoresist may be removed by an acceptable ashing or stripping process, such as using an oxygen plasma or the like. Once the photoresist is removed, exposed portions of the seed layer are removed, such as by using an acceptable etching process, such as by wet or dry etching.
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The metallization pattern 130 is then formed. The metallization pattern 130 includes portions on and extending along the major surface of the dielectric layer 128. The metallization pattern 130 further includes portions extending through the dielectric layer 128 to physically and electrically couple the metallization pattern 126. The metallization pattern 130 may be formed in a similar manner and of a similar material as the metallization pattern 126. In some embodiments, the metallization pattern 130 has a different size than the metallization pattern 126. For example, the conductive lines and/or vias of the metallization pattern 130 may be wider or thicker than the conductive lines and/or vias of the metallization pattern 126. Further, the metallization pattern 130 may be formed to a greater pitch than the metallization pattern 126.
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The metallization pattern 134 is then formed. The metallization pattern 134 includes portions on and extending along the major surface of the dielectric layer 132. The metallization pattern 134 further includes portions extending through the dielectric layer 132 to physically and electrically couple the metallization pattern 130. The metallization pattern 134 may be formed in a similar manner and of a similar material as the metallization pattern 126. The metallization pattern 134 is the topmost metallization pattern of the front-side redistribution structure 122. As such, all of the intermediate metallization patterns of the front-side redistribution structure 122 (e.g., the metallization patterns 126 and 130) are disposed between the metallization pattern 134 and the integrated circuit dies 50. In some embodiments, the metallization pattern 134 has a different size than the metallization patterns 126 and 130. For example, the conductive lines and/or vias of the metallization pattern 134 may be wider or thicker than the conductive lines and/or vias of the metallization patterns 126 and 130. Further, the metallization pattern 134 may be formed to a greater pitch than the metallization pattern 130.
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The openings 160 may facilitate heat transfer away from the integrated circuit dies 50 by increasing a number of heat dissipation surfaces in the first package component 100. For example, the sidewalls of the openings 160 may provide additional heat dissipation surfaces in the first package component 100. In some embodiments, the openings 160 may further facilitate process integration by allowing subsequent features to be inserted in the openings 160. For example, in some embodiments, heat transfer structures, EMI shielding structures, mechanical braces, or the like may be subsequently inserted in the openings 160 for improved structural integrity and/or performance in the resulting semiconductor package. The openings 160 may each have a maximum width W2 that is in a range of 0.05 mm to 10 mm.
The openings 160 may have any suitable shape. For example, referring to
In other embodiments, referring to
In other embodiments, referring to
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In other embodiments, edge openings 160 (e.g., as illustrated by
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The substrate 202 may include active and passive devices (not shown). A wide variety of devices such as transistors, capacitors, resistors, combinations of these, and the like may be used to generate the structural and functional requirements of the design for the second package components 200. The devices may be formed using any suitable methods.
The substrate 202 may also include metallization layers (not shown) and the conductive vias 208. The metallization layers may be formed over the active and passive devices and are designed to connect the various devices to form functional circuitry. The metallization layers may be formed of alternating layers of dielectric material (e.g., low-k dielectric material) and conductive material (e.g., copper) with vias interconnecting the layers of conductive material and may be formed through any suitable process (such as deposition, damascene, dual damascene, or the like). In some embodiments, the substrate 202 is substantially free of active and passive devices.
The substrate 202 may have bond pads 204 on a first side of the substrate 202 to couple to the stacked dies 210, and bond pads 206 on a second side of the substrate 202, the second side being opposite the first side of the substrate 202, to couple to the conductive connectors 152. In some embodiments, the bond pads 204 and 206 are formed by forming recesses (not shown) into dielectric layers (not shown) on the first and second sides of the substrate 202. The recesses may be formed to allow the bond pads 204 and 206 to be embedded into the dielectric layers. In other embodiments, the recesses are omitted as the bond pads 204 and 206 may be formed on the dielectric layer. In some embodiments, the bond pads 204 and 206 include a thin seed layer (not shown) made of copper, titanium, nickel, gold, palladium, the like, or a combination thereof. The conductive material of the bond pads 204 and 206 may be deposited over the thin seed layer. The conductive material may be formed by an electro-chemical plating process, an electroless plating process, CVD, atomic layer deposition (ALD), PVD, the like, or a combination thereof. In an embodiment, the conductive material of the bond pads 204 and 206 is copper, tungsten, aluminum, silver, gold, the like, or a combination thereof.
In some embodiments, the bond pads 204 and the bond pads 206 are UBMs that include three layers of conductive materials, such as a layer of titanium, a layer of copper, and a layer of nickel. Other arrangements of materials and layers, such as an arrangement of chrome/chrome-copper alloy/copper/gold, an arrangement of titanium/titanium tungsten/copper, or an arrangement of copper/nickel/gold, may be utilized for the formation of the bond pads 204 and 206. Any suitable materials or layers of material that may be used for the bond pads 204 and 206 are fully intended to be included within the scope of the current application. In some embodiments, the conductive vias 208 extend through the substrate 202 and couple at least one of the bond pads 204 to at least one of the bond pads 206.
In the illustrated embodiment, the stacked dies 210 are coupled to the substrate 202 by wire bonds 212, although other connections may be used, such as conductive bumps. In an embodiment, the stacked dies 210 are stacked memory dies. For example, the stacked dies 210 may be memory dies such as low-power (LP) double data rate (DDR) memory modules, such as LPDDR1, LPDDR2, LPDDR3, LPDDR4, or the like memory modules.
The stacked dies 210 and the wire bonds 212 may be encapsulated by a molding material 214. The molding material 214 may be molded on the stacked dies 210 and the wire bonds 212, for example, using compression molding. In some embodiments, the molding material 214 is a molding compound, a polymer, an epoxy, silicon oxide filler material, the like, or a combination thereof. A curing process may be performed to cure the molding material 214; the curing process may be a thermal curing, a UV curing, the like, or a combination thereof.
In some embodiments, the stacked dies 210 and the wire bonds 212 are buried in the molding material 214, and after the curing of the molding material 214, a planarization step, such as a grinding, is performed to remove excess portions of the molding material 214 and provide a substantially planar surface for the second package components 200.
After the second package components 200 are formed, the second package components 200 are mechanically and electrically bonded to the first package component 100 by way of conductive connectors 152 and a metallization pattern of the front-side redistribution structure 122. In some embodiments, the stacked dies 210 may be coupled to the integrated circuit dies 50A and 50B through the wire bonds 212, the bond pads 204 and 206, the conductive connectors 152, and the front-side redistribution structure 122.
The conductive connectors 152 may be ball grid array (BGA) connectors, solder balls, metal pillars, controlled collapse chip connection (C4) bumps, micro bumps, electroless nickel-electroless palladium-immersion gold technique (ENEPIG) formed bumps, or the like. The conductive connectors 152 may include a conductive material such as solder, copper, aluminum, gold, nickel, silver, palladium, tin, the like, or a combination thereof. In some embodiments, the conductive connectors 152 are formed by initially forming a layer of solder through evaporation, electroplating, printing, solder transfer, ball placement, or the like. Once a layer of solder has been formed on the structure, a reflow may be performed in order to shape the material into the desired bump shapes. In another embodiment, the conductive connectors 150 comprise metal pillars (such as a copper pillar) formed by sputtering, printing, electro plating, electroless plating, CVD, or the like. The metal pillars may be solder free and have substantially vertical sidewalls. In some embodiments, a metal cap layer is formed on the top of the metal pillars. The metal cap layer may include nickel, tin, tin-lead, gold, silver, palladium, indium, nickel-palladium-gold, nickel-gold, the like, or a combination thereof and may be formed by a plating process.
The conductive connectors 152 may be formed to extend through the dielectric layer 136 to contact the metallization pattern 134. Openings are formed through the dielectric layer 136 to expose portions of the metallization pattern 134. The openings may be formed, for example, using laser drilling, etching, or the like. The conductive connectors 152 are formed in the openings. In some embodiments, the conductive connectors 152 comprise flux and are formed in a flux dipping process. In some embodiments, the conductive connectors 152 comprise a conductive paste such as solder paste, silver paste, or the like, and are dispensed in a printing process.
In some embodiments, a solder resist (not shown) is formed on the side of the substrate 202 opposing the stacked dies 210. The conductive connectors 152 may be disposed in openings in the solder resist to be electrically and mechanically coupled to conductive features (e.g., the bond pads 206) in the substrate 202. The solder resist may be used to protect areas of the substrate 202 from external damage.
In some embodiments, the conductive connectors 152 have an epoxy flux (not shown) formed thereon before they are reflowed with at least some of the epoxy portion of the epoxy flux remaining after the second package components 200 are attached to the first package component 100.
In some embodiments, an underfill 220 is formed between the first package component 100 and the second package components 200, surrounding the conductive connectors 152. The underfill may reduce stress and protect the joints resulting from the reflowing of the conductive connectors 152. The underfill may be formed by a capillary flow process after the second package components 200 are attached, or may be formed by a suitable deposition method before the second package components 200 are attached. In embodiments where the epoxy flux is formed, it may act as the underfill. Although the underfill 220 is illustrated as being wholly above the opening 160, in other embodiments, the underfill 220 may extend partially into an upper portion of the opening 160.
As further illustrated by
The package substrate 300 includes a substrate core 302 and bond pads 304 over the substrate core 302. The substrate core 302 may be made of a semiconductor material such as silicon, germanium, diamond, or the like. Alternatively, compound materials such as silicon germanium, silicon carbide, gallium arsenic, indium arsenide, indium phosphide, silicon germanium carbide, gallium arsenic phosphide, gallium indium phosphide, combinations of these, and the like, may also be used. Additionally, the substrate core 302 may be an SOI substrate. Generally, an SOI substrate includes a layer of a semiconductor material such as epitaxial silicon, germanium, silicon germanium, SOI, SGOI, or combinations thereof. The substrate core 302 is, in one alternative embodiment, based on an insulating core such as a fiberglass reinforced resin core. One example core material is fiberglass resin such as FR4. Alternatives for the core material include bismaleimide-triazine BT resin, or alternatively, other PCB materials or films. Build up films such as ABF or other laminates may be used for substrate core 302.
The substrate core 302 may include active and passive devices (not shown). A wide variety of devices such as transistors, capacitors, resistors, combinations of these, and the like may be used to generate the structural and functional requirements of the design for the device stack. The devices may be formed using any suitable methods.
The substrate core 302 may also include metallization layers and vias (not shown), with the bond pads 304 being physically and/or electrically coupled to the metallization layers and vias. The metallization layers may be formed over the active and passive devices and are designed to connect the various devices to form functional circuitry. The metallization layers may be formed of alternating layers of dielectric material (e.g., low-k dielectric material) and conductive material (e.g., copper) with vias interconnecting the layers of conductive material and may be formed through any suitable process (such as deposition, damascene, dual damascene, or the like). In some embodiments, the substrate core 302 is substantially free of active and passive devices.
The package substrate 300 may further include external connectors 310 on under bump metallization (UBMs) 312. Conductive connectors 310 are formed on the UBMs 312. The conductive connectors 310 may be ball grid array (BGA) connectors, solder balls, metal pillars, controlled collapse chip connection (C4) bumps, micro bumps, electroless nickel-electroless palladium-immersion gold technique (ENEPIG) formed bumps, or the like. The conductive connectors 310 may include a conductive material such as solder, copper, aluminum, gold, nickel, silver, palladium, tin, the like, or a combination thereof. In some embodiments, the conductive connectors 310 are formed by initially forming a layer of solder through evaporation, electroplating, printing, solder transfer, ball placement, or the like. Once a layer of solder has been formed on the structure, a reflow may be performed in order to shape the material into the desired bump shapes. In another embodiment, the conductive connectors 310 comprise metal pillars (such as copper pillars) formed by a sputtering, printing, electro plating, electroless plating, CVD, or the like. The metal pillars may be solder free and have substantially vertical sidewalls. In some embodiments, a metal cap layer is formed on the top of the metal pillars. The metal cap layer may include nickel, tin, tin-lead, gold, silver, palladium, indium, nickel-palladium-gold, nickel-gold, the like, or a combination thereof and may be formed by a plating process. The conductive connectors 310 may be used to attach the package substrate 300 to another package component, such as a printed circuit board (PCB), mother board, another package substrate or the like.
In some embodiments, the conductive connectors 150 are reflowed to attach the first package component 100 to the bond pads 304. The conductive connectors 150 electrically and/or physically couple the package substrate 300, including metallization layers in the substrate core 302, to the first package component 100. In some embodiments, a solder resist 306 is formed on the substrate core 302. The conductive connectors 150 may be disposed in openings in the solder resist 306 to be electrically and mechanically coupled to the bond pads 304. The solder resist 306 may be used to protect areas of the substrate 202 from external damage.
The conductive connectors 150 may have an epoxy flux (not shown) formed thereon before they are reflowed with at least some of the epoxy portion of the epoxy flux remaining after the first package component 100 is attached to the package substrate 300. This remaining epoxy portion may act as an underfill to reduce stress and protect the joints resulting from reflowing the conductive connectors 150. In some embodiments, an underfill 308 may be formed between the first package component 100 and the package substrate 300 and surrounding the conductive connectors 150. The underfill 308 may be formed by a capillary flow process after the first package component 100 is attached or may be formed by a suitable deposition method before the first package component 100 is attached.
In some embodiments, passive devices (e.g., surface mount devices (SMDs), not shown) may also be attached to the first package component 100 (e.g., to the UBMs 138) or to the package substrate 300 (e.g., to the bond pads 304). For example, the passive devices may be bonded to a same surface of the first package component 100 or the package substrate 300 as the conductive connectors 150. The passive devices may be attached to the package component 100 prior to mounting the first package component 100 on the package substrate 300, or may be attached to the package substrate 300 prior to or after mounting the first package component 100 on the package substrate 300.
Other features and processes may also be included. For example, testing structures may be included to aid in the verification testing of the 3D packaging or 3DIC devices. The testing structures may include, for example, test pads formed in a redistribution layer or on a substrate that allows the testing of the 3D packaging or the 3DIC, the use of probes and/or probe cards, and the like. The verification testing may be performed on intermediate structures as well as the final structure. Additionally, the structures and methods disclosed herein may be used in conjunction with testing methodologies that incorporate intermediate verification of known good dies to increase the yield and decrease costs.
Thus, a completed semiconductor package 400 comprising a first package component 100, a second package component 200, and a package substrate 300 is provided. The first package component 100 comprises integrated circuit dies 50 that are electrically connected to each other by fan-out structures, specifically, the redistribution structures 122 and 106. The first package component 100 may comprise one or more openings 160 disposed therein, which help facilitate the transfer of heat away from the integrated circuit dies 50 in the first package component by increasing a number of heat dissipation surfaces in the first package component 100. For example, the sidewalls of the openings 160 may provide additional heat dissipation surfaces in the first package component 100. The openings 160 may extend completely through the first package component 100 as illustrated by
In some embodiments, the openings 160 may facilitate process integration by allowing additional features to be inserted in the openings 160. For example,
As illustrated in
In some embodiments, the openings 160 may facilitate process integration by allowing additional features to be inserted in the openings 160. As another example,
Although
The devices may be interconnected by an interconnect structure 506 comprising, for example, metallization patterns 506A in one or more dielectric layers 506B (also referred to as insulating material layers 506B) on the semiconductor substrate 502. The dielectric layers 506B may be formed of dielectric materials that are deposited by CVD processes and patterned using damascene processes (e.g., single damascene processes, dual damascene processes, or the like). As an example of a damascene process, a dielectric layer 506B may be deposited, and openings may be patterned in the dielectric layer 506B (e.g., with photolithography and/or etching). Subsequently, the openings in the dielectric layer 506B may be filled with a conductive material, and excess conductive material may be removed through a planarization process (e.g., a chemical mechanical polish (CMP) or the like) to form a metallization pattern 506A. The interconnect structures 506 electrically connect the devices on the substrate 502 to form one or more integrated circuits. Although
The interposer 500 further includes through vias 501, which may be electrically connected to the metallization patterns 506A in the interconnect structure 506. The through vias 501 may comprise a conductive material (e.g., copper, or the like) and may extend from a metallization pattern 506A into the substrate 502. One or more insulating barrier layers 503 may be formed around at least portions of the through vias 501 in the substrates 502. The insulating barrier layers 503 may comprise, for example, silicon oxide, silicon nitride, silicon oxynitride, or the like, and may be used to physically and electrically isolate the through vias 501 from each other and the substrate 502. In subsequent processing steps, the substrate 502 may be thinned to expose the through vias 501 (see
In an embodiment, the interposer 500 further comprises contact pads 508, which allow connections to be made to the interconnect structure 506 and the devices on the substrate 502. The contact pads 508 may comprise copper, aluminum (e.g., 28K aluminum), or another conductive material. The contact pads 508 are electrically connected to the metallization patterns 506A of the interconnect structure 506. One or more passivation films may be disposed on the interconnect structure 506, and the contact pads 508. For example, the interconnect structure 506 may include passivation films 510 and 512. The passivation films 510 and 512 may each comprise an inorganic material, such as silicon oxide, silicon oxynitride, silicon nitride, or the like. In some embodiments, the materials of the passivation films 510 and 512 may be the same or different from each other. Further, the materials of the passivation films 510 and 512 may be the same or different from the materials of the dielectric layers 506B. In some embodiments, the contact pads 508 extend over and cover edges of the passivation film 510, and the passivation film 512 extends over and covers edges of the contact pads 508.
UBMs 514 are formed for external connection to one or more integrated circuit dies. The UBMs 514 have bump portions on and extending along the major surface of the passivation film 512, and have via portions extending through the passivation film 512 to physically and electrically couple the contact pads 508. As a result, the UBMs 514 are electrically coupled to the metallization patterns 506A and the through vias 501. The UBMs 514 may be formed of the same material and process as the metallization patterns 126 described above.
The interposer 500 may be formed as part of a larger wafer (e.g., connected to other interposers 500). In some embodiments, the interposers 500 may be singulated from each other after packaging. Subsequently, as illustrated by the embodiments of
In the illustrated embodiment, the integrated circuit dies 50 are attached to the interposer 500 with solder bonds, such as conductive connectors 526 on UBMs 528 of the integrated circuit dies 50. The integrated circuit dies 50 may be placed on the interposer 500 using, e.g., a pick-and-place tool. The conductive connectors 526 may be formed a similar material and a similar method as described above with respect to the conductive connectors 152 described above (see
As also illustrated in
Subsequently, a backside the substrate 502 is thinned to expose the through vias 501. Exposure of the through vias 501 may be accomplished by a thinning process, such as a grinding process, a chemical-mechanical polish (CMP), an etch-back, combinations thereof, or the like. In some embodiments (not separately illustrated), the thinning process for exposing the through vias 501 includes a CMP, and the through vias 501 protrude at the back-side of the interposer 500 as a result of dishing that occurs during the CMP. In such embodiments, an insulating layer (not separately illustrated) may optionally be formed on the back surface of the substrate 502, surrounding the protruding portions of the through vias 501. The insulating layer may be formed of a silicon-containing insulator, such as, silicon nitride, silicon oxide, silicon oxynitride, or the like, and may be formed by a suitable deposition method such as spin coating, CVD, plasma-enhanced CVD (PECVD), high density plasma CVD (HDP-CVD), or the like. After the substrate 502 is thinned, the exposed surfaces of the through vias 501 and the insulating layer (if present) or the substrate 502 are coplanar (within process variations) such that they are level with one another, and are exposed at the back-side of the interposer 500.
In
Conductive connectors 522 are formed on the UBMs 520. The conductive connectors 522 may be ball grid array (BGA) connectors, solder balls, metal pillars, controlled collapse chip connection (C4) bumps, micro bumps, electroless nickel-electroless palladium-immersion gold technique (ENEPIG) formed bumps, or the like. The conductive connectors 522 may include a conductive material such as solder, copper, aluminum, gold, nickel, silver, palladium, tin, the like, or a combination thereof. In some embodiments, the conductive connectors 522 are formed by initially forming a layer of solder through evaporation, electroplating, printing, solder transfer, ball placement, or the like. Once a layer of solder has been formed on the structure, a reflow may be performed in order to shape the material into the desired bump shapes. In another embodiment, the conductive connectors 522 comprise metal pillars (such as copper pillars) formed by a sputtering, printing, electro plating, electroless plating, CVD, or the like. The metal pillars may be solder free and have substantially vertical sidewalls. In some embodiments, a metal cap layer is formed on the top of the metal pillars. The metal cap layer may include nickel, tin, tin-lead, gold, silver, palladium, indium, nickel-palladium-gold, nickel-gold, the like, or a combination thereof and may be formed by a plating process.
A singulation process is performed by cutting along scribe line regions of the interposer 500. The singulation process may include sawing, dicing, or the like. For example, the singulation process can include sawing the encapsulant 120, the interconnect structure 506, and the substrate 502. The singulation process singulates each package 100′ from adjacent packages 100′. The singulation process forms interposers 500 from the singulated portions of the interposer wafer. As a result of the singulation process, the outer sidewalls of the interposer 500 (including the interconnect structure 506, the passivation layers 510/512, and substrate 502) and the encapsulant 120 are laterally coterminous (within process variations). Further the encapsulant 120 may completely surround the integrated circuit dies 50 in a plan view.
The package 100′ will be attached to a package substrate 300, by flip chip bonding, with the conductive connectors 522. The underfill 308 may be formed around the conductive connectors 522 between the first package component 100′ and the package substrate 300, and the openings 160 may be formed through the package 100′, thus completing formation of the integrated circuit package. The openings 160 may have any of the configurations and/or be formed by any of the processes described above with respect to
Referring first to
In
An underfill 620 may be formed around the conductive connectors 614, and between the redistribution structure 600 and the integrated circuit dies 50. The underfill 620 may reduce stress and protect the joints resulting from the reflowing of the conductive connectors 614. The underfill 620 may be formed a similar material and a similar method as described above with respect to the underfill 308. The encapsulant 120 may be then formed around the integrated circuit dies 50 and the underfill 620 over the redistribution structure 600.
A singulation process is performed by cutting along scribe line regions of the redistribution structure 600. The singulation process may include sawing, dicing, or the like. For example, the singulation process can include sawing the encapsulant 120 and the redistribution structure 600. The singulation process singulates each package 100″ from adjacent packages 100″. The singulation process forms redistribution structure 600 from the singulated portions of the wafer. As a result of the singulation process, the outer sidewalls of the redistribution structure 600 and the encapsulant 120 are laterally coterminous (within process variations). Further the encapsulant 120 may completely surround the integrated circuit dies 50 in a plan view.
Conductive connectors 622 and UBMs 624 are formed extending through the dielectric layer 602 to contact the metallization pattern 604. Openings are formed through the dielectric layer 602 to expose portions of the metallization pattern 604. The openings may be formed, for example, using laser drilling, etching, or the like. The conductive connectors 622/the UBMs 625 are formed in the openings. The conductive connectors 622/the UBMs 624 may be formed a similar material and a similar method as described above with respect to the conductive connectors 150/the UBMS 514 described above (see
The first package component 100″ is then attached to the package substrate 300, by flip chip bonding, with the conductive connectors 622. The underfill 308 may be formed around the conductive connectors 622 between the first package component 100″ and the package substrate 300, and the openings 160 may be formed through the package 100″, thus completing formation of the integrated circuit package. The openings 160 may have any of the configurations and/or be formed by any of the processes described above with respect to
Referring first to
In
Next in
A singulation process is performed by cutting along scribe line regions of the fan-out structure 700. The singulation process may include sawing, dicing, or the like. For example, the singulation process can include sawing the encapsulant 120 and the fan-out structure 700. The singulation process singulates each package 100″′ from adjacent packages 100′″. The singulation process forms fan-out structure 700 from the singulated portions of the wafer. As a result of the singulation process, the outer sidewalls of the fan-out structure 700 and the encapsulant 120 are laterally coterminous (within process variations). Further the encapsulant 120 may completely surround the integrated circuit dies 50 in a plan view.
The first package component 100′″ is then attached to the package substrate 300, by flip chip bonding, with the conductive connectors 722. The underfill 308 may be formed around the conductive connectors 722 between the first package component 100′″ and the package substrate 300, and the openings 160 may be formed through the package 100″′, thus completing formation of the integrated circuit package. The openings 160 may have any of the configurations and/or be formed by any of the processes described above with respect to
In accordance with some embodiments, one or more integrated circuit dies are electrically connected by a fan-out structure (e.g., a redistribution structure, an interposer, a local silicon interconnect (LSI), or the like), and the integrated circuit dies may be encapsulated for further packaging with other package components (e.g., a package substrate or the like). One or more openings may be formed in the molding compound and/or the fan-out structure. The inclusion of the openings may facilitate thermal dissipation of heat away from the semiconductor dies through the openings. As another example, the openings may facilitate the insertion of one or more advantageous components, such as a thermal dissipation feature, electromagnetic interference (EMI) shields, structural support (e.g., mechanical braces), or the like. As a result, improved package performance and/or manufacturing ease may be achieved.
In some embodiments, a semiconductor package includes a first package component comprising: an integrated circuit die; an encapsulant surrounding the integrated circuit die; and a fan-out structure electrically connected to the integrated circuit die, wherein a first opening extends completely through the fan-out structure and at least partially through the encapsulant in a cross-sectional view, and wherein the encapsulant at least completely surrounds the first opening in a top-down view. The semiconductor package further includes a package substrate bonded to the first package component. Optionally, in some embodiments, the first opening extends completely through the first package component. Optionally, in some embodiments, the first opening extends completely through the package substrate. Optionally, in some embodiments, a second opening extends completely through the fan-out structure and at least partially through the encapsulant in the cross-sectional view, wherein the encapsulant only partially surrounds the second opening in the top-down view. Optionally, in some embodiments, the semiconductor package further includes a brace in the opening, wherein the brace extends at least partially into the package substrate. Optionally, in some embodiments, the mechanical brace extends completely through the package substrate. Optionally, in some embodiments, the fan-out structure comprises a redistribution structure. Optionally, in some embodiments, the fan-out structure comprises an interposer. Optionally, in some embodiments, the fan-out structure comprises a local silicon interconnect (LSI) die. Optionally, in some embodiments, the semiconductor package further includes through vias extending through the encapsulant.
In some embodiments, a semiconductor package includes a first package component comprising: a first integrated circuit die; a second integrated circuit die; an encapsulant surrounding the first integrated circuit die and the second integrated circuit die; a fan-out structure electrically connecting the first integrated circuit die to the second integrated circuit die; and a conductive package component extending through the fan-out structure into the encapsulant, wherein the conductive package component is a high thermal conductivity component, an EMI shielding component, or a combination thereof. The semiconductor package further includes a package substrate bonded to the first package component. Optionally, in some embodiments, the conductive package component comprises copper or aluminum. Optionally, in some embodiments, the conductive package component only extends partially through the encapsulant. Optionally, in some embodiments, the conductive package component only extends completely through the encapsulant.
In some embodiments, a method of manufacturing a semiconductor package includes forming a first package component, forming the first package component comprising: encapsulating an integrated circuit die in a molding compound; forming a redistribution structure over the molding compound and the integrated circuit die, wherein the redistribution structure is electrically connected to the integrated circuit die; after forming the redistribution structure, patterning an opening extending through the redistribution structure into the encapsulant. The method further includes bonding a package substrate to the first package component. Optionally, in some embodiments, patterning the opening comprises laser machining, mechanical drilling/routing, plasma etching/bombardment, or chemical etching. Optionally, in some embodiments, the method further includes placing a mechanical brace in the opening, the mechanical brace securing the first package component to the package substrate. Optionally, in some embodiments, the method further includes placing a package component in the opening, wherein the package component is a high thermal conductivity component, an EMI shielding component, or a combination thereof. Optionally, in some embodiments, after patterning the opening, a portion of the molding compound remains disposed directly under the opening. Optionally, in some embodiments, patterning the opening comprises patterning the opening through the molding compound.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
This application claims the benefit of U.S. Provisional Application No. 63/365,353, filed on May 26, 2022, which application is hereby incorporated herein by reference.
Number | Date | Country | |
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63365353 | May 2022 | US |