This invention relates generally to semiconductor processing, and more particularly to semiconductor chips incorporating thru-silicon-vias and methods of fabricating the same.
Some time ago semiconductor chip designers began stacking multiple semiconductor dice (aka “dies”) vertically in order to obtain more functionality without an attendant increase in required package substrate or circuit board area. A variety of techniques have been used to electrically connect adjacent dice in such stacked arrangements. One technique has involved the use of wire bonds leading from contact pads on one die to corresponding contact pads on an adjacent die. Another technique that has been introduced more recently involves the use of so-called thru-silicon-vias (TSV). A typical TSV is a conductive via that extends nearly or perhaps entirely through a semiconductor chip, depending on the presence or absence of any intervening conductor pads at one or the other of the principal surfaces of the chip.
A typical conventional TSV provides electrical routing between opposite principal surfaces of a semiconductor chip. On one side, the conventional TSV is connected to some type of input/output structure (I/O), which is often a solder bump designed to form a solder joint with a package substrate during flip-chip solder reflow. The TSV is not connected directly to the solder bump, but to some intervening structure, such as an outermost metallization structure like a bump pad. The other or backside end of the TSV is connected to some form of backside I/O structure, typically through some intermediary conductor structure. The conventional TSV arrangement includes a single TSV metallurgically joined to a single bump pad.
Conventional TSVs are subjected to Joule heating and electromigration issues that vary in intensity depending on power levels, thermal management, die size and other factors. A one-to-one TSV to bump pad arrangement is subjected to such environmental considerations.
The present invention is directed to overcoming or reducing the effects of one or more of the foregoing disadvantages.
In accordance with one aspect of the present invention, a method of manufacturing is provided that includes forming a first plurality of conductive vias in a layer of a first semiconductor chip. The first plurality of conductive vias includes first ends and second ends. A first conductor pad is formed in ohmic contact with the first ends of the first plurality of conductive vias.
In accordance with another aspect of the present invention, a method of manufacturing is provided that includes forming a first plurality of conductive vias in a layer of a first semiconductor chip. The first plurality of conductive vias includes first ends and second ends. The first semiconductor chip has a first side and a second and opposite side. A first conductor is formed proximate the first side and in ohmic contact with the first ends of the first plurality of conductive vias. A second conductor is formed proximate the second side and in ohmic contact with the second ends of the first plurality of conductive vias.
In accordance with another aspect of the present invention, an apparatus is provided that includes a first semiconductor chip that has a layer and a first conductor pad coupled to the first semiconductor chip. A first plurality of conductive vias traverses the layer and has first ends and second ends. The first ends are in ohmic contact with the first conductor pad.
The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
Various embodiments of a semiconductor chip device that includes two or more stacked substrates are described herein. One example includes at least one semiconductor chip with plural TSVs. However, plural TSVs are formed in ohmic contact with a given conductor structure, such as a bump or pillar pad. With redundancy in TSV-to-pad connections, failure of a given TSV need not open circuit the pad. Additional details will now be described.
In the drawings described below, reference numerals are generally repeated where identical elements appear in more than one figure. Turning now to the drawings, and in particular to
The exemplary structures of the semiconductor chip 15 disclosed herein are not dependent on a particular electronic functionality. Thus, the semiconductor chip IS and the semiconductor chip 25 may be any of a myriad of different types of circuit devices used in electronics, such as, for example, microprocessors, graphics processors, combined microprocessor/graphics processors, application specific integrated circuits, memory devices, active optical devices, such as lasers, or the like, and may be single or multi-core or even stacked laterally with additional dice. Furthermore, one or both of the semiconductor chips 15 and 25 could be configured as an interposer with or without some logic circuits. Thus the term “chip” includes an interposer. The semiconductor chips 15 and 25 may be constructed of bulk semiconductor, such as silicon or germanium, or semiconductor on insulator materials, such as silicon-on-insulator materials, or other chip materials.
The exemplary structures of the semiconductor chip 15 disclosed herein are not dependent on a particular electronic circuit board functionality. Thus, the circuit board 20 may be a semiconductor chip package substrate, a circuit card, or virtually any other type of printed circuit board. Although a monolithic structure could be used for the circuit board 20, a more typical configuration will utilize a buildup design. In this regard, the circuit board 20 may consist of a central core upon which one or more buildup layers are formed and below which an additional one or more buildup layers are formed. The core itself may consist of a stack of one or more layers. If implemented as a semiconductor chip package substrate, the number of layers in the circuit board 20 can vary from four to sixteen or more, although less than four may be used. So-called “coreless” designs may be used as well. The layers of the circuit board 20 may consist of an insulating material, such as various well-known epoxies, interspersed with metal interconnects. A multi-layer configuration other than buildup could be used. Optionally, the circuit board 20 may be composed of well-known ceramics or other materials suitable for package substrates or other printed circuit boards. The circuit board 20 is provided with a number of conductor traces and vias and other structures (not visible) in order to provide power, ground and signals transfers between the semiconductor chips 15 and 25 and another device, such as another circuit board for example. The circuit board 20 may be electrically connected to another device (not shown) by way of an input/output array such as the ball grid array depicted. The ball grid array includes the aforementioned plural solder balls 35 metallurgically bonded to respective ball pads (not shown). The ball pads (not shown) are interconnected to various conductor pads in the circuit board 20 by way of plural interconnect traces and vias and other structures that are not shown.
Additional details of the semiconductor chip 15 will be described in conjunction with
The semiconductor chip 15 is a multi-strata structure in that there may be a bulk stratum or layer 80, a device stratum or layer 85 in which large numbers of transistors, capacitors and other circuit devices may be formed, and a metallization stratum or layer 75. The metallization layer 75 may be formed as a series of metallization layers sandwiched between interlevel dielectric layers that are successively built up on the device layer 85. Because the semiconductor chip 15 is designed to have another semiconductor chip, such as the semiconductor chip 25, stacked thereon, a backside metallization scheme is provided. In this regard, a redistribution layer (RDL) 90 may be formed on the semiconductor layer 80. The RDL 90 may be monolithic or a laminate structure of one or more layers of build-up or other wise deposited insulating material interwoven with one or more RDL metallization structures that may be on the same or different levels. In this illustrative embodiment, RDL metallization structures 95 and 100 are visible. The RDL 90 may be topped with an insulating or passivation layer 105 and plural input/output structures 110. The passivation layer 105 may be monolithic or a laminate of plural insulating films and may be composed of the same types of materials used for the passivation structure layer 60 described elsewhere herein. The input/output structures 110 may be conductive pillars, pads, solder joints or the like, and are used to establish electrical interfaces with the semiconductor chip 25 depicted in
To establish conducting pathways between opposite sides 112 and 113 of the semiconductor chip 15, and more particularly between the RDL structures 95 and 100 and the conductor pads 65 and 70, plural TSVs, three of which are visible and labeled 115, 120 and 125, may be formed in the semiconductor layer 80 to extend through the device layer 85 and the metallization layer 75 and join the RDL structure 95 to the conductor pad 65. In this way, respective ends 127 of the TSVs contact the conductor pad 65 and opposite ends 129 thereof contact the RDL structure 95. A similar plurality of TSVs 130, 135 and 140 may join the RDL structure 100 to the conductor pad 70 electrically. It should be understood that the terms “TSV” and “semiconductor” are used generically herein, in that the semiconductor layer 80 may be composed of material(s) other than silicon, and even of insulating materials such as silicon dioxide, tetra-ethyl-ortho-silicate or others. Unlike a conventional semiconductor chip design utilizing a single TSV per pad, the embodiments disclosed herein utilize plural TSVs for a given conductor pad, such as the TSVs 115, 120 and 125 and the conductor pad 65. The use of multiple TSVs for a given conductor pad provides improved spread of thermal stresses and lowers current density and thus Joule heating, which can enhance electromigration lifespan. With multiple TSVs connected to a given conductor pad, the failure of one of the TSVs due to, for example, a stress migration fracture, can be compensated for by the other remaining TSVs. The TSVs 115, 120, 125, 130, 135 and 140 may be composed of a variety of materials, such as copper, tungsten, graphene, aluminum, platinum, gold, palladium, alloys of these or like. Clad structures are envisioned.
Additional details of the TSVs 115, 120 and 125 may be understood by referring now to
Attention is now turned to
As noted above, the arrangement of TSVs tied to a given conductor pad may be subject to great variation. In this regard, attention is now turned to
In the foregoing illustrative embodiments, the various TSVs are fabricated as a continuous structure from top to bottom, that is, through the semiconductor device layer 85 and metallization layer 75 shown in
An exemplary process for forming the plural TSVs may be understood by referring now to
Referring now to
Following the removal of the etch mask 178 shown in
To enable the TSVs 115, 120, 125, 130, 135 and 140 to establish ohmic contact with structures in the later-formed RDL 90 shown in
Referring again to
Any of the exemplary embodiments disclosed herein may be embodied in instructions disposed in a computer readable medium, such as, for example, semiconductor, magnetic disk, optical disk or other storage medium or as a computer data signal. The instructions or software may be capable of synthesizing and/or simulating the circuit structures disclosed herein. In an exemplary embodiment, an electronic design automation program, such as Cadence APD, Cadence Spectra, Encore or the like, may be used to synthesize the disclosed circuit structures. The resulting code may be used to fabricate the disclosed circuit structures.
While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
Number | Name | Date | Kind |
---|---|---|---|
4645546 | Matsushita | Feb 1987 | A |
20050064707 | Sinha | Mar 2005 | A1 |
20060202347 | Egawa | Sep 2006 | A1 |
20080136023 | Komai et al. | Jun 2008 | A1 |
20080237806 | Uchiyama | Oct 2008 | A1 |
20090261458 | Bae et al. | Oct 2009 | A1 |
20090294983 | Cobbley et al. | Dec 2009 | A1 |
20100032843 | Chen et al. | Feb 2010 | A1 |
20110140126 | Gaul | Jun 2011 | A1 |
Number | Date | Country |
---|---|---|
2007194669 | Aug 2007 | JP |
2009295616 | Dec 2009 | JP |
2010135348 | Jun 2010 | JP |
2007024009 | Mar 2007 | WO |
Entry |
---|
Kiegler et al., Copper Deposition for Pillars and Vias, Semiconductor Manufacturing Magazine, vol. 7, Issue 8, dated Aug. 2006, 6 pages. |
PCT/US2011/051027 International Search Report mailed Oct. 28, 2011, 14 pages. |
Number | Date | Country | |
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20230031099 A1 | Feb 2023 | US |
Number | Date | Country | |
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Parent | 15247259 | Aug 2016 | US |
Child | 17963729 | US | |
Parent | 12878542 | Sep 2010 | US |
Child | 15247259 | US |