Embodiments of the present disclosure relate to the field of integrated circuits, and more particularly, to techniques, structures, and configurations of recessed semiconductor substrates for package assemblies.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Integrated circuit devices, such as transistors, are formed on dies or chips that continue to scale in size to smaller dimensions. The shrinking dimensions of the dies are challenging conventional substrate fabrication and/or package assembly technologies that are currently used to route electrical signals to or from the semiconductor die. For example, laminate substrate technologies may not produce sufficiently small features on a substrate to correspond with the finer pitches of interconnects or other signal-routing features formed on the dies.
In one embodiment, the present disclosure provides a method comprising providing a semiconductor substrate having (i) a first surface and (ii) a second surface that is disposed opposite to the first surface, forming a dielectric film on the first surface of the semiconductor substrate, forming a redistribution layer on the dielectric film, electrically coupling one or more dies to the redistribution layer, forming a molding compound on the semiconductor substrate, recessing the second surface of the semiconductor substrate, forming one or more channels through the recessed second surface of the semiconductor substrate to expose the redistribution layer; and forming one or more package interconnect structures in the one or more channels, the one or more package interconnect structures being electrically coupled to the redistribution layer, the one or more package interconnect structures to route electrical signals of the one or more dies.
In another embodiment, the present disclosure provides an apparatus comprising a semiconductor substrate having (i) a first surface and (ii) a second surface that is disposed opposite to the first surface, a dielectric film formed on the first surface of the semiconductor substrate, a redistribution layer formed on the dielectric film, one or more dies electrically coupled to the redistribution layer, a molding compound formed on the semiconductor substrate, one or more channels formed through the second surface of the semiconductor substrate, and one or more package interconnect structures disposed in the one or more channels, the one or more package interconnect structures being electrically coupled to the redistribution layer through the one or more channels to route electrical signals of the one or more dies.
Embodiments of the present disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments herein are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.
Embodiments of the present disclosure describe techniques, structures, and configurations for a semiconductor substrate having a recessed region and associated package assemblies. In the following detailed description, reference is made to the accompanying drawings which form a part hereof, wherein like numerals designate like parts throughout. Other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.
The description may use perspective-based descriptions such as up/down, over/under, and/or top/bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of embodiments described herein to any particular orientation.
For the purposes of the present disclosure, the phrase “A/B” means A or B. For the purposes of the present disclosure, the phrase “A and/or B” means “(A), (B), or (A and B).” For the purposes of the present disclosure, the phrase “at least one of A, B, and C” means “(A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).” For the purposes of the present disclosure, the phrase “(A)B” means “(B) or (AB)” that is, A is an optional element.
Various operations are described as multiple discrete operations in turn, in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed and/or described operations may be omitted in additional embodiments.
The description uses the phrases “in an embodiment,” “in embodiments,” or similar language, which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous.
The semiconductor substrate 102 includes a first surface, A1, and a second surface, A2, that is disposed opposite to the first surface A1. The first surface A1 and the second surface A2 generally refer to opposing surfaces of the semiconductor substrate 102 to facilitate the description of various configurations described herein.
According to various embodiments, a portion of the second surface A2 is recessed to provide a thickness, T, that facilitates the formation of one or more channels 104 through the semiconductor substrate 102. In some embodiments, the semiconductor substrate 102 is recessed to have a thickness T between about 10 microns and about 500 microns. The thickness is not limited to this range and other thicknesses, both greater and smaller, can be used in other embodiments.
The semiconductor substrate 102 is fabricated using technologies similar to those that are generally known to fabricate integrated circuit (IC) structures on a die or chip. For example, well-known patterning processes such as lithography/etch and/or deposition processes for fabricating IC devices on a die can be used to form features of the semiconductor substrate 102. By using semiconductor fabrication techniques, the semiconductor substrate 102 can include smaller features than other types of substrates such as laminate (e.g., organic) substrates. The semiconductor substrate 102 facilitates routing of electrical signals, such as input/output (I/O) and/or power/ground signals, for dies, which continue to shrink in size. For example, in some embodiments, the semiconductor substrate 102 allows for fine pitch Si-to-Si interconnects and final line routing between the semiconductor substrate 102 and one or more dies 108.
A dielectric film 105 is formed on the first surface A1 and/or the second surface A2 of the semiconductor substrate. The dielectric film 105 can include, for example, silicon dioxide (SiO2), silicon nitride (SiN), silicon oxynitride (Si2N2O), or other suitable dielectric materials. The dielectric film 105 generally provides electrical isolation for electrically conductive material disposed on the semiconductor substrate to prevent current leakage between the electrically conductive material and the semiconductor material (e.g., silicon) of the semiconductor substrate.
One or more redistribution layers 106 are formed on the dielectric film 105 to route the electrical signals of the one or more dies 108 that are coupled to the semiconductor substrate 102. For example, the one or more redistribution layers 106 can provide electrical routing between the one or more dies 108 and one or more package interconnect structures 114 disposed in the one or more channels 104.
The one or more redistribution layers 106 generally include an electrically conductive material such as, for example, a metal (e.g., copper or aluminum). Other suitable electrically conductive materials can be used to form the one or more redistribution layers 106 in other embodiments.
The one or more redistribution layers 106 can include a variety of structures to route the electrical signals such as, for example, pads, lands, or traces. Although not depicted, a passivation layer comprising an electrically insulative material such as polyimide, for example, can be deposited on the one or more redistribution layers 106 and patterned to provide openings in the passivation layer to allow electrical coupling of the one or more dies 108 to the one or more redistribution layers 106.
One or more dies 108 are coupled to the semiconductor substrate 102. The one or more dies 108 generally comprise a semiconductor material, such as, for example, silicon. In an embodiment, the one or more dies 108 and the semiconductor substrate 102 are fabricated using the same semiconductor material to reduce stress associated with heating/cooling mismatch of materials such as, for example, mismatched coefficients of thermal expansion (CTE).
The one or more dies 108 can be coupled to the semiconductor substrate 102 using any suitable configuration. The one or more dies 108 generally have an active side that includes a surface upon which a plurality of integrated circuit (IC) devices (not shown) such as transistors for logic and/or memory are formed and an inactive side that is disposed opposite to the active side. The active side of the one or more dies 108 is electrically coupled to the one or more redistribution layers 106.
In some embodiments, the active side of the one or more dies 108 is coupled to the one or more redistribution layers 106 using one or more bumps 110 in a flip-chip configuration, as can be seen. In other embodiments, the active side of the one or more dies 108 is electrically coupled to the one or more redistribution layers 106 using other structures, such as, for example, one or more bonding wires to provide a wire-bonding configuration.
The one or more bumps 110 generally comprise an electrically conductive material such as, for example, solder or other metal to route the electrical signals of the one or more dies 108. According to various embodiments, the one or more bumps 110 comprise lead, gold, tin, copper, or lead-free materials, or combinations thereof. The one or more bumps 110 can have a variety of shapes including spherical, cylindrical, rectangular, or other shapes and can be formed using a bumping process, such as, for example, a controlled collapse chip connect (C4) process, stud-bumping, or other suitable process.
Although not shown, one or more other active or passive components can be mounted on the semiconductor substrate 102. The components can include Electronic Compounds and integrated circuits (ICs). The components can include, for example, filter components, resistors, inductors, power amplifiers, capacitors, or packaged ICs. Other active or passive components can be coupled to the semiconductor substrate 102 in other embodiments.
A molding compound 112 is disposed on the first surface A1 of the semiconductor substrate 102. The molding compound 112 generally comprises an electrically insulative material, such as a thermosetting resin, that is disposed to protect the one or more dies 108 from moisture, oxidation, or chipping associated with handling. In some embodiments, the molding compound 112 is disposed to substantially encapsulate the one or more dies 108 and substantially fill a region between the one or more dies 108 and the semiconductor substrate 102 (e.g., between the one or more bumps 110), as can be seen. The molding compound 112 can be selected to have a coefficient of thermal expansion (CTE) that is substantially the same or similar to a CTE of the semiconductor substrate 102 and/or the one or more dies 108 to reduce stress associated with mismatched CTE materials.
According to various embodiments, one or more channels 104, which may also be referred to as vias, are formed through the recessed surface (e.g., the second surface A2) of the semiconductor substrate 102. The one or more channels 104 are filled with an electrically conductive and/or thermally conductive material such as a metal used to form one or more package interconnect structures 114. The one or more channels 104 generally provide an electrical and/or thermal pathway between the first surface A1 and the second surface A2 of the semiconductor substrate 102. In an embodiment where the semiconductor substrate 102 comprises silicon, the one or more channels 104 are one or more through-silicon vias (TSVs). In some embodiments, the one or more channels 104 are tapered. The one or more channels 104 can be straight or have other shapes in other embodiments.
One or more package interconnect structures 114 such as, for example, one or more solder balls or posts are disposed in the one or more channels 104 to further route the electrical signals of the one or more dies 108. The one or more package interconnect structures 114 are electrically coupled to the one or more redistribution layers 106 through the one or more channels 104. In the depicted embodiment of
The one or more package interconnect structures 114 generally comprise an electrically conductive material such as a metal. The one or more package interconnect structures 114 can be formed in a variety of shapes including spherical, planar, or polygon shapes and can be positioned in a variety of positions including in a row or in an array of multiple rows. Although the one or more package interconnect structures 114 are depicted on a peripheral portion of the semiconductor substrate 102, the one or more package interconnect structures 114 can be disposed on or near a central portion of the semiconductor substrate 102 in other embodiments.
The package assembly 100 can be electrically coupled to another electronic device 150 using the one or more package interconnect structures 114 to further route the electrical signals of the one or more dies 108 to the other electronic device 150. The other electronic device 150 can include, for example, as a printed circuit board (PCB) (e.g., motherboard), a module, or another package assembly.
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In the depicted embodiment of
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The molding compound 112 can be used in conjunction with an underfill layer (e.g., underfill 118 of
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The one or more package interconnect structures 114 can be formed according to a variety of suitable techniques including, for example, screen printing, electrical plating, and/or solder ball placement. The one or more package interconnect structures 114 can be configured in a variety of ways including, for example, a ball-grid array (BGA) configuration.
The underfill 118 can be formed, for example, prior to forming the molding compound 112 (e.g., as shown in the package assembly 200 of
The molding compound 112 can be formed such that a backside surface of the one or more dies 108 is exposed to facilitate heat dissipation. In one embodiment, the molding compound 112 can be deposited using a mold that allows the molding compound 112 to be formed such that the backside surface of the one or more dies 108 is exposed. In other embodiments, the molding compound can be deposited to encapsulate the one or more dies and, subsequently, the molding compound can be recessed to expose the backside surface of the one or more dies 108.
At 404, the method 400 further includes forming a dielectric film (e.g., the dielectric film 105 of
At 406, the method 400 further includes forming a redistribution layer (e.g., the one or more redistribution layers 106 of
At 408, the method 400 further includes electrically coupling one or more dies (e.g., the one or more dies 108 of
At 410, the method 400 further includes forming a molding compound (e.g., the molding compound 112 of
At 412, the method 400 further includes recessing a surface (e.g., the second surface A2 of
At 414, the method 400 further includes forming one or more channels (e.g., the one or more channels 104 of
At 416, the method 400 further includes forming one or more under bump metallization (UBM) structures (e.g., the one or more UBM structures 116 of
At 418, the method 400 further includes forming one or more package interconnect structures (e.g., the one or more package interconnect structures 114 of
Although certain embodiments have been illustrated and described herein, a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments illustrated and described without departing from the scope of the present disclosure. This disclosure is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments described herein be limited only by the claims and the equivalents thereof.
This disclosure is a continuation of U.S. application Ser. No. 13/007,059, filed Jan. 14, 2011, which claims priority to U.S. Provisional Patent Application No. 61/301,125, filed Feb. 3, 2010, and to U.S. Provisional Patent Application No. 61/316,282, filed Mar. 22, 2010, and to U.S. Provisional Patent Application No. 61/321,068, filed Apr. 5, 2010, and to U.S. Provisional Patent Application No. 61/325,189, filed Apr. 16, 2010. The disclosures of the applications referenced above are incorporated herein by reference in their entireties.
Number | Date | Country | |
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61325189 | Apr 2010 | US | |
61321068 | Apr 2010 | US | |
61316282 | Mar 2010 | US | |
61301125 | Feb 2010 | US |
Number | Date | Country | |
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Parent | 13007059 | Jan 2011 | US |
Child | 14153892 | US |