The present disclosure relates generally to the field of semiconductor package systems and, more particularly, to interposers of 3-dimensional integrated circuit (3D IC) package systems and methods of designing the same.
Since the invention of integrated circuits, the semiconductor industry has experienced continual rapid growth due to continuous improvements in the integration density of various electronic components (i.e., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, allowing for the integration of more components into a given area.
These integration improvements are essentially two-dimensional (2D) in nature, in that the volume occupied by the integrated components is essentially on the surface of the semiconductor wafer. Although dramatic improvements in lithography have resulted in considerable improvements in 2D integrated circuit formation, there are physical limits to the density that can be achieved in two dimensions. One of these limits is the minimum size needed to make these components. Also, when more devices are put into one chip, more complex designs are required.
An additional limitation comes from the significant increase in the number and length of interconnections between devices as the number of devices increases. When the number and length of interconnections increase, both circuit resistance-capacitance (RC) delay and power consumption increase.
Three-dimensional integrated circuits (3D IC) are therefore created to resolve the above-discussed limitations. In a conventional formation process of 3D IC, two wafers, each including an integrated circuit, are formed. The wafers are then bonded with the devices aligned. Deep vias are then formed to interconnect devices on the first and second wafers.
Much higher device density has been achieved using 3D IC technology, and up to several layers of wafers have been bonded. As a result, the total wire length is significantly reduced. The number of vias is also reduced. Accordingly, 3D IC technology has the potential of being the mainstream technology of the next generation.
Methods for forming 3D IC include die-to-wafer bonding, wherein separate dies are bonded to a common wafer. An advantageous feature of the die-to-wafer bonding is that the size of the dies may be smaller than the size of chips on the wafer.
Recently, through-silicon-vias (TSVs), also referred to as through-wafer vias, are increasingly used as a way of implementing 3D IC. In one method a bottom wafer is bonded to a top wafer. Both wafers include integrated circuits over substrates. The integrated circuits in the bottom wafer are connected to the integrated circuits in the wafer through interconnect structures. The integrated circuits in the wafers are further connected to external pads through through-silicon-vias. The stacked wafers can be subjected to a sawing process to provide a plurality of stacked die structures.
The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the numbers and dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
A package system has a silicon interposer disposed between silicon dies and a board substrate. The silicon interposer has a redistribution layer (RDL) for electrical connections between the silicon dies and a plurality of through-silicon-via (TSV) structures for an electrical connection between the silicon dies and the board substrate. The functionality of the silicon dies can be tested before assembly. However, the silicon dies are subjected to the risk that the interposer fails. If good silicon dies are bonded with a failed interposer, the whole package system is still failed and the good silicon dies are wasted and cannot be recovered. To the applicants' knowledge, the passive interposer does not include any circuits and/or devices for testing the RDL and the TSV structures.
Based on the foregoing, interposers with testing structures and methods of designing the interposers are desired.
It is understood that 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. 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. Moreover, the formation of a feature on, connected to, and/or coupled to another feature in the present disclosure that follows may include embodiments in which the features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the features, such that the features may not be in direct contact. In addition, spatially relative terms, for example, “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top,” “bottom,” etc. as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) are used for ease of the present disclosure of one features relationship to another feature. The spatially relative terms are intended to cover different orientations of the device including the features.
Referring to
The dimension, e.g., diameter, of the bumps 125 is smaller than that of the bumps 105. In some embodiments, the bumps 125 can be referred to as micro bumps, the bumps 105 can be referred to as Controlled Collapse Chip Connection (C4) bumps and the bumps 103 can be referred to as solder/package bumps. In other embodiments, the bumps 125 can have a diameter of about 15 μm or less. The bumps 105 can have a diameter of about 50 μm or less.
Referring again to
In some embodiments, the interposer 110 can include at least one passive device, e.g., a capacitor, a resistor, and/or an inductor. In other embodiments, the interposer 110 can be substantially free from including any active device, e.g., metal-oxide-semiconductor (MOS) transistors, bipolar junction transistors (BJTs), complementary MOS (CMOS) transistors, etc. In still other embodiments, the interposer 110 does not include any active device or passive device. The interposer 110 can be merely configured for providing an electrical connection. In yet still other embodiments, the interposer 110 can be referred to as a passive interposer.
In some embodiments, the substrate 111 may include an elementary semiconductor including silicon or germanium in crystal, polycrystalline, or an amorphous structure; 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; any other suitable material; or combinations thereof. In at least one embodiment, the alloy semiconductor substrate may have a gradient SiGe feature in which the Si and Ge composition change from one ratio at one location to another ratio at another location of the gradient SiGe feature. In another embodiment, the alloy SiGe is formed over a silicon substrate. In another embodiment, a SiGe substrate is strained. Furthermore, the semiconductor substrate may be a semiconductor on insulator, such as a silicon on insulator (SOI), or a thin film transistor (TFT). In some examples, the semiconductor substrate may include a doped epitaxial (epi) layer or a buried layer. In other examples, the compound semiconductor substrate may have a multilayer structure, or the substrate may include a multilayer compound semiconductor structure.
In some embodiments, the RDL 115 can include a plurality of electrical connection structures (not labeled), e.g., via plugs, contact plugs, dual damascene structures, damascene structures, metallic routing lines, other electrical connection structures, and/or any combinations thereof. In some embodiments, electrical connection structures of the RDL 115 can be made of at least one material, such as tungsten, aluminum, copper, titanium, tantalum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, other proper conductive materials, and/or combinations thereof.
In some embodiments, the bumps 103, 105 and/or 125 can each be disposed on respective bonding pads (not shown). The bonding pads can be made of at least one material, such as copper (Cu), aluminum (Al), aluminum copper (AlCu), aluminum silicon copper (AlSiCu), or other conductive material or various combinations thereof. In some embodiments, the bonding pads may include an under bump metallization (UBM) layer. In some embodiments, the bumps 103, 105 and/or 125 can each be made of at least one material, such as a lead-free alloy (e.g., gold (Au), a tin/silver/copper (Sn/Ag/Cu) alloy, or other lead-free alloys), a lead-containing alloy (e.g., a lead/tin (Pb/Sn) alloy), copper, aluminum, aluminum copper, conductive polymer, other bump metal materials, or any combinations thereof.
In some embodiments, the bumps 221a, 223a, 225a and 227a can be electrically coupled with the bumps 221b, 223b, 225b and 227b through metallic lines 222, 224, 226 and 228, respectively, of the RDL 115 of the interposer 110 shown in
Following are descriptions illustrating exemplary methods for testing electrical connection among the bumps 221a-221b, 223a-223b, 225a-225b and 227a-227b through the electrical connection structures of the RDL 115. As noted, the probe pads 211a-211b, 213a-213b, 215a-215b and 217a-217b are electrically coupled with the respective bumps 221a-221b, 223a-223b, 225a-225b and 227a-227b. Whether the electrical connection structures of the RDL 115 are short or open can be promptly tested by probing the probe pads. As being disposed in spaces where no bumps are disposed, the probe the probe pads 211a-211b, 213a-213b, 215a-215b and 217a-217b may not cost or increase additional areas for the interposer 110.
In some embodiments checking if the electrical connection between the bumps 221a and 221b is open, a probe pin 212a is applied to the probe pad 211a and another probe pin 212b is applied to the probe pad 211b. A voltage value of a logic state, e.g., a logic state “1”, can be applied to the probe pad 211a through the probe pin 212a. If the same voltage value can be detected on the probe pad 211b, it is assumed that the bump 221a is electrically connected with the bump 221b and the electrical connection structure of the RDL 115 between the bumps 221a and 221b is accepted. If no voltage value is detected on the probe pad 211b, it is assumed that the electrical connection between the bumps 221a and 221b is open and the interposer 110 fails.
In other embodiments checking if the bump 221a is short to other bumps 223a-223b, 225a-225b and 227a-227b, the probe pin 212a is applied to the probe pad 211a and other probe pins (not shown) are applied to the probe pads 213a-213b, 215a-215b and 217a-217b. A voltage of a logic state, e.g., a logic state “1”, can be applied to the probe pad 211a through the probe pin 212a. If no voltage value is detected on the probe pads 213a-213b, 215a-215b and 217a-217b, it is assumed that the bump 221a is not short to the bumps 223a-223b, 225a-225b and 227a-227b. If the same voltage value can be detected on at least one of the probe pads 213a-213b, 215a-215b and 217a-217b, it is assumed that the bump 221a is short to at least one of the bumps 223a-223b, 225a-225b and 227a-227b and the interposer 110 fails.
Following are descriptions regarding structures and methods for testing electrical connections between bumps 105 and 125 through the RDL 115 and the TSV structures 117 (shown in
In some embodiments, the bumps 241a, 245a and 243b can be electrically coupled with the bumps 241b, 245b and 227b through metallic lines 261, 265 and 267, respectively. In some embodiments, the metallic lines 261, 265 and 267 disposed on the surface 110a and represented with solid lines. The metallic lines 261 can be made of at least one material, such as tungsten, aluminum, copper, titanium, tantalum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, other proper conductive materials, and/or combinations thereof.
In some embodiments, the bumps 241a are electrically coupled with each other through an electrical connection structure 330a of the RDL 115 (shown in
Referring to
Referring to
As noted, the bumps 241a are electrically coupled with the bumps 241b through the metallic line 261 as shown in
In some embodiments checking if the TSV structures 310a are short to other TSV structures e.g., TSV structures under the bumps 243a-243b and 245a-245b (shown in
Referring again to
For example,
In some embodiments, the interposer 110 includes at least one TSV structure, e.g., TSV structures 610a. The TSV structures 610a can be partially and/or completely misaligned from the bumps 541a in a direction that is orthogonal to the surface 110a of the interposer 110. In some embodiments, the bump 620a is electrically coupled with the bumps 541a through the TSV structures 610a and the electrical connection structure 630a. With the numbers of the TSV structures 610a and/or the bumps 541a, the bump 620a, the TSV structures 610a and the bumps 541a can be configured for power and/or signal transmissions. It is noted that the numbers and/or arrangement of the bumps and TSV structures described above in conjunction with
In at least this embodiment, the TSV structure 602a is provided solely for the TSV electrical connection test. The TSV structures 602a and 602d are not configured to provide power and/or signal transmissions through the interposer 110. In the situation that the electrical connection through the TSV structures 602a and 602d is accepted, it is assumed that the electrical connection through the TSV structures 610a is more likely to be accepted. In some embodiments, the TSV structures 602a and 602d can be referred to as dummy TSV structures. Here, the term “dummy TSV structure” means that the TSV structure is provided for the electrical connection test, not for power/signal transmission.
As noted, the numbers of the bumps 541a and/or TSV structures 610a, 602a can be modified. For example,
As shown in
Referring again to
As shown in
In some embodiments, no TSV structure is disposed between the probe pad and the bumps. For example,
As shown in
As noted, the bumps 841a can be randomly deployed and/or around the probe pad 811a as long as the TSV structures 910c can be electrically coupled with the bumps 841a through the electrical connection structure 930a. For example, the bumps 841a can each be disposed adjacent to the opposite side of the probe pad 811a as shown in
In some embodiments, the probe pad disposed adjacent to a first surface of the interposer and the bump that is disposed adjacent to a second surface of the interposer are misaligned from each other along a direction that is orthogonal to the first surface. For example,
As shown in
For example, few bumps 941a can be disposed adjacent to the probe pad 911a as shown in
In other embodiments, a single TSV structure 1010c can be disposed directly under a bump 941a as shown in
In still other embodiments, few bumps 941a can be disposed adjacent to the probe pad 911a as shown in
In yet other embodiments, a single TSV structure 941a is disposed over the surface 110a and electrically coupled with the bump 1020a through the single TSV structure 1010c for a signal transmission as shown in
Following are description associated with exemplary methods of designing an interposer.
For example, the block 671 can include providing a layout database of the interposer 110 (shown in
In some embodiments, the block 673 includes allocating a first and second probe pads in a first and second spaces, respectively, around the plurality of bumps. For example, the probe pads 211a-211b, 213a-213b, 215a-215b and 217a-217b can be allocated in spaces around the bumps 221a-221c, 223a-223b, 225a-225b, 227a-227b, 241a-241b, 243a-243b, 245a-245b and 247a. For example, the probe pads 211a-211b, 213a-213b and 215a-215b can be allocated in spaces that are surrounded by the bumps 221a-221c, 223a-223b, 225a-225b, 227a-227b, 241a-241b, 243a-243b and 245a-245b, respectively. In other embodiments, the pad 217a can be allocated at the space that is adjacent to the bumps 247a. In still other embodiments, the pad 217b can be solely allocated and distant from the bumps.
In some embodiments, the block 675 includes routing a first metallic line between the first probe pad and the first bump. For example, the metallic lines 231a-231b, 233a-233b, 235a-235b and 237a-237b can be routed between the probe pads 211a-211b, 213a-213b, 215a-215b, 217a-217b and the bumps 221a-221b, 223a-223b, 225a-225b, 227a-227b, respectively.
In some embodiments, the method 600 can optionally include comparing distances of the first bump to the first and second probe pads, and determining if the distance between the first probe pad and the first bump is shorter than the distance between the second probe pad and the first bump, wherein if the distance between the first probe pad and the first bump is shorter than the distance between the second probe pad and the first bump, and the first metallic line is routed between the first probe pad and the first bump. For example, routing the metallic line 231a between the probe pad 211a and the bump 221a can include comparing distances of the bump 211a to the probe pad 211a and 211b. As shown in
In some embodiments, the method 600 can optionally include allocating the second probe pad in the second space that are surrounded by at least one fourth bump of the plurality of bumps that are disposed on the surface of the interposer, and routing a second metallic line between the second probe pad and the second bump. For example, the probe pad 211b can be allocated in the space that is surrounded by the bumps 241b. The metallic line 221b is routed between the probe pad 211b and the bump 221b.
In some embodiments, the method 600 can optionally route a third metallic line between the at least one third bump and the at least one fourth bump. For example, the metallic line 261 can be routed between the bumps 241a and 241b.
In a first embodiment of this application, an interposer of a package system includes a first probe pad disposed adjacent to a first surface of the interposer. A second probe pad is disposed adjacent to the first surface of the interposer. A first bump of a first dimension is disposed adjacent to the first surface of the interposer. The first bump is electrically coupled with the first probe pad. A second bump of the first dimension is disposed adjacent to the first surface of the interposer. The second bump is electrically coupled with the second probe pad. The second bump is electrically coupled with the first bump through a redistribution layer (RDL) of the interposer.
In a second embodiment of this application, a method of designing an interposer of a package system includes providing a layout database of an interposer including at least one electrical connection structure among a plurality of bumps that are disposed on a surface of the interposer, wherein the plurality of bumps includes a first bump and a second bump. A first and second probe pads are allocated in a first and second spaces, respectively, around the plurality of bumps. A first metallic line is routed between the first probe pad and the first bump.
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.
The present application claims priority of U.S. Provisional Patent Application Ser. No. 61/480,117, filed on Apr. 28, 2011, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61480117 | Apr 2011 | US |