Embodiments of the present disclosure generally relate to the field of semiconductor packaging, and in particular to inductors.
Continued growth in virtual machines and cloud computing will continue to increase the demand for increased power to semiconductor packaging components.
Embodiments described herein may be related to apparatuses, processes, and techniques related to inductors located within a substrate. In embodiments, the inductors may be created in a glass core using a laser-assisted etching of glass interconnects techniques, which may be referred to as “LEGIT” techniques, to create trenches or vias within the glass substrate into which conductive material may be placed to create the inductor. In embodiments, the inductors may be low equivalent series resistance (ESR) compact air-core inductors. In embodiments, the resistance of the inductance may be decreased by extending the trace thickness based on varying via or trench sizes or depths inside the glass core. In embodiments, the trace width may be narrow and limited to a minimum via diameter allowed by the LEGIT technique.
Embodiments described herein may be directed to in-package inductors with large trace thicknesses, narrow widths, and close spacing between individual turns. In embodiments, the inductors may include spirals formed in a glass core using the LEGIT technique using blind vias, which also may be referred to as trenches. Embodiments described herein may result in high inductance and low series resistance, facilitate a small inductor form factor which leads to smaller package sizes, and smaller traces spacing that leads to strong inductive coupling between neighboring turns and therefore leads to some mutual inductance. The resulting total inductance is the sum of the mutual inductance between the turns and the self-inductance of the turns. In embodiments, the inductors may provide efficient power delivery to electronic circuits, including CPUs and graphic cores. In addition, in embodiments, the inductors operate without additional magnetic material being added within or proximate to the inductor structure, and may operate just using traces that include copper or other conductive elements.
Inductors with low inductance values, for example <5 nH, and ESR in the order of few milli-Ohms may be needed for power delivery on die and on-package. Using legacy techniques, achieving a low series resistance and typical inductance value simultaneously is challenging. In legacy implementations, and order to circumvent the resistance challenge, magnetic materials have been introduced to enhance the self-inductance while keeping the length of the conductor (within the inductor) short. These legacy techniques help with the ESR reduction as the resistance is proportional to the length of the conductor. However, introducing magnetic material on die or on package is typically expensive and very complex. As a result, in legacy implementations magnetics are typically used when there are no alternative solutions. These legacy techniques may result in: large inductors that lead to package form factor increases, increased package layer accounts that lead to higher costs, and large devices that obstruct non-package signal routing.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments in which the subject matter of the present disclosure may be practiced. It is to be understood that 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.
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 “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).
The description may use perspective-based descriptions such as top/bottom, in/out, over/under, and the like. 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.
The description may use the phrases “in an embodiment,” or “in embodiments,” 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 term “coupled with,” along with its derivatives, may be used herein. “Coupled” may mean one or more of the following. “Coupled” may mean that two or more elements are in direct physical or electrical contact. However, “coupled” may also mean that two or more elements indirectly contact each other, but yet still cooperate or interact with each other, and may mean that one or more other elements are coupled or connected between the elements that are said to be coupled with each other. The term “directly coupled” may mean that two or more elements are in direct contact.
Various operations may be 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.
As used herein, the term “module” may refer to, be part of, or include an ASIC, an electronic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
Various Figures herein may depict one or more layers of one or more package assemblies. The layers depicted herein are depicted as examples of relative positions of the layers of the different package assemblies. The layers are depicted for the purposes of explanation, and are not drawn to scale. Therefore, comparative sizes of layers should not be assumed from the Figures, and sizes, thicknesses, or dimensions may be assumed for some embodiments only where specifically indicated or discussed.
Diagram 100 shows a high level process flow for a through and blind drill in a microelectronic package substrate (e.g. glass) using LEGIT to create a through via or a blind via. A through via 112 is created by laser pulses from two laser sources 102, 104 on opposite sides of a glass wafer 106. As used herein, a through drill and a through via refers to when the drill or the via starts on one side of the glass/substrate and ends on the other side. A blind drill and a blind via refers to when the drill or the via starts on the surface of the substrate and stops half way inside the substrate. In embodiments, the laser pulses from the two laser sources 102, 104 are applied perpendicularly to the glass wafer 106 to induce a morphological change 108, which may also be referred to as a structural change, in the glass that encounters the laser pulses. This morphological change 108 includes changes in the molecular structure of the glass to make it easier to etch out (remove a portion of the glass). In embodiments, a wet etch process may be used.
Diagram 120 shows a high level process flow for a double blind shape. A double blind shape 132, 133 may be created by laser pulses from two laser sources 122, 124, which may be similar to laser sources 102, 104, that are on opposite sides of the glass wafer 126, which may be similar to glass wafer 106. In this example, adjustments may be made in the laser pulse energy and/or the laser pulse exposure time from the two laser sources 122, 124. As a result, morphological changes 128, 129 in the glass 126 may result, with these changes making it easier to etch out portions of the glass. In embodiments, a wet etch process may be used.
Diagram 140 shows a high level process flow for a single-blind shape, which may also be referred to as a trench. In this example, a single laser source 142 delivers a laser pulse to the glass wafer 146 to create a morphological change 148 in the glass 146. As described above, these morphological changes make it easier to etch out a portion of the glass 152. In embodiments, a wet etch process may be used.
Diagram 160 shows a high level process flow for a through via shape. In this example, a single laser source 162 applies a laser pulse to the glass 166 to create a morphological change 168 in the glass 166, with the change making it easier to etch out a portion of the glass 172. As shown here, the laser pulse energy and/or laser pulse exposure time from the laser source 162 has been adjusted to create an etched out portion 172 that extends entirely through the glass 166.
With respect to
In embodiments using the process described with respect to
Trench 204 may be created in the substrate 202 in a variety of patterns. Trench 204 may take the form of a spiral, or of some other form that may be used to implement an inductor in the substrate 202. If the substrate 202 is a glass substrate, the LEGIT technique as described above with respect to
In embodiments, the trench 204 may be filled with a conductive material 206, such as copper or some other conductive metal or element. In embodiments, for trench widths less than 50 microns, the trench 204 may be fully filled with the conductive material 206. For larger width trenches, the conductive material 206 may be conformally plated within the trench 204. The conductive material 206, when placed in the trench 204, may also be referred to as a trace of the inductor. In embodiments, the conductive material 206 may extend partially into the substrate 202, as shown with respect to diagram 220 and 240, or the conductive material 206 may extend completely through the substrate 202 as shown in diagram 245.
As shown with respect to diagram 245, the LEGIT technique may be used to create a through via similar to trench 204 that extends completely through the substrate 202. Conductive material 206 may be subsequently added to either completely fill, partially fill, or be conformally plated to the sides of the trench 204. In embodiments, portions of the trench 204 may extend completely through the substrate 202, while other portions of the trench 204 extend only partially into the substrate 202.
In embodiments, a surface pad 208 may be electrically coupled with the conductive material 206. The surface pad 208 may be placed above a surface of the substrate 202 as shown in diagram 220. In embodiments, the surface pad 208 may be placed at or below a surface of the substrate 202 as shown in diagrams 240 and 245. In embodiments, an etching process, such as the LEGIT technique described in
Diagram 260 shows a horizontal cross-section of the inductor 200. Note that the conductive material 206 forms a single track spiral within the substrate 202. The width of the conductive material 206, and the spacing between the spirals may be adjusted based on a number of operational factors. In one example, a conductive material 206 made of copper that is inserted within the class substrate 202 may have different coefficients of expansion (CTE). For example, the CT of copper is 16, where the CTE of glass varies from 0.6 to 9. This may affect how close the conductive material 206 may come to itself, as well as how deep the trench 204 may be etched. In embodiments, the different CTE may also affect the whether multiple trenches are used, as discussed further below with respect to
In addition, the sides or the bottom of the conductive material 206 that extends into the substrate 202 may not be straight. For example, the sides of the bottom may be tapered. This may be due to different LEGIT techniques, as described above with respect to
Legacy inductors may have low mutual inductance between the turns, resulting in a large footprint. In addition, legacy inductors may obstruct other signals being routed inside the package. In addition, legacy inductors also come with increased package stack up because multiple layers have to be stacked to achieve low ESR.
In embodiments, a multi-track spiral inductor utilizes narrow trenches when there is a large difference between the coefficient of thermal expansion of the conductive filling and the glass. For example, for a copper-filled trench in a glass with CTE of 0.6, the trench width may be between 5 and 20 μm. Many of those trenches can then be connected in parallel to reduce the ESR. If the CTE of glass is close to 9, the trench width may be 40 μm and thus it may not be necessary to connect several of those trenches in parallel.
As shown, the conductive material 506, 507 may be electrically coupled using a pad 508. In embodiments, the pad 508 may be disposed on top of the substrate 502, as shown in cross-section 520, or may be partially or completely recessed within the substrate 502 as shown in cross-section 540. The pad 508 may be continuous, or may be intermittent, causing electrical coupling between the conductive material 506, 507 at one or more points along the inductor 500. In other embodiments, one or more of the trenches 504, 505 may be vias that extend completely through the substrate 502. In these embodiments, another pad, which may be similar to pad 508, may be placed on the opposite side of the substrate 502 to electrically couple the conductive material of the inductor 500.
At block 602, the process includes etching a glass substrate to create one or more spiral trenches. In embodiments, the glass substrate may be similar to glass substrate 106, 126, 146, 166 of
At block 604, the process may further include inserting conductive material into the one or more spiral trenches. In embodiments, the spiral trenches may be similar to trenches 204 of
At block 606, the process may further include applying a surface pad to the glass substrate that is electrically coupled with the conductive material. In embodiments, the surface pad may be similar to pads 208 of
In an embodiment, the electronic system 700 is a computer system that includes a system bus 720 to electrically couple the various components of the electronic system 700. The system bus 720 is a single bus or any combination of busses according to various embodiments. The electronic system 700 includes a voltage source 730 that provides power to the integrated circuit 710. In some embodiments, the voltage source 730 supplies current to the integrated circuit 710 through the system bus 720.
The integrated circuit 710 is electrically coupled to the system bus 720 and includes any circuit, or combination of circuits according to an embodiment. In an embodiment, the integrated circuit 710 includes a processor 712 that can be of any type. As used herein, the processor 712 may mean any type of circuit such as, but not limited to, a microprocessor, a microcontroller, a graphics processor, a digital signal processor, or another processor. In an embodiment, the processor 712 includes, or is coupled with, all or part of inductors in trenches within a substrate, as disclosed herein. In an embodiment, SRAM embodiments are found in memory caches of the processor. Other types of circuits that can be included in the integrated circuit 710 are a custom circuit or an application-specific integrated circuit (ASIC), such as a communications circuit 714 for use in wireless devices such as cellular telephones, smart phones, pagers, portable computers, two-way radios, and similar electronic systems, or a communications circuit for servers. In an embodiment, the integrated circuit 710 includes on-die memory 716 such as static random-access memory (SRAM). In an embodiment, the integrated circuit 710 includes embedded on-die memory 716 such as embedded dynamic random-access memory (eDRAM).
In an embodiment, the integrated circuit 710 is complemented with a subsequent integrated circuit 711. Useful embodiments include a dual processor 713 and a dual communications circuit 715 and dual on-die memory 717 such as SRAM. In an embodiment, the dual integrated circuit 710 includes embedded on-die memory 717 such as eDRAM.
In an embodiment, the electronic system 700 also includes an external memory 740 that in turn may include one or more memory elements suitable to the particular application, such as a main memory 742 in the form of RAM, one or more hard drives 744, and/or one or more drives that handle removable media 746, such as diskettes, compact disks (CDs), digital variable disks (DVDs), flash memory drives, and other removable media known in the art. The external memory 740 may also be embedded memory 748 such as the first die in a die stack, according to an embodiment.
In an embodiment, the electronic system 700 also includes a display device 750, an audio output 760. In an embodiment, the electronic system 700 includes an input device such as a controller 770 that may be a keyboard, mouse, trackball, game controller, microphone, voice-recognition device, or any other input device that inputs information into the electronic system 700. In an embodiment, an input device 770 is a camera. In an embodiment, an input device 770 is a digital sound recorder. In an embodiment, an input device 770 is a camera and a digital sound recorder.
As shown herein, the integrated circuit 710 can be implemented in a number of different embodiments, including all or part of inductors in trenches within a substrate, according to any of the several disclosed embodiments and their equivalents, an electronic system, a computer system, one or more methods of fabricating an integrated circuit, and one or more methods of fabricating an electronic assembly that includes a package substrate implementing all or part of inductors in trenches within a substrate, according to any of the several disclosed embodiments as set forth herein in the various embodiments and their art-recognized equivalents. The elements, materials, geometries, dimensions, and sequence of operations can all be varied to suit particular I/O coupling requirements including array contact count, array contact configuration for a microelectronic die embedded in a processor mounting substrate according to any of the several disclosed processes used for inductors in trenches within a substrate embodiments and their equivalents. A foundation substrate may be included, as represented by the dashed line of
Various embodiments may include any suitable combination of the above-described embodiments including alternative (or) embodiments of embodiments that are described in conjunctive form (and) above (e.g., the “and” may be “and/or”). Furthermore, some embodiments may include one or more articles of manufacture (e.g., non-transitory computer-readable media) having instructions, stored thereon, that when executed result in actions of any of the above-described embodiments. Moreover, some embodiments may include apparatuses or systems having any suitable means for carrying out the various operations of the above-described embodiments.
The above description of illustrated embodiments, including what is described in the Abstract, is not intended to be exhaustive or to limit embodiments to the precise forms disclosed. While specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the embodiments, as those skilled in the relevant art will recognize.
These modifications may be made to the embodiments in light of the above detailed description. The terms used in the following claims should not be construed to limit the embodiments to the specific implementations disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
The following paragraphs describe examples of various embodiments.
Example 1 is an inductor comprising: a substrate having a first side and a second side opposite the first side; a trench extending from the first side of the substrate toward the second side of the substrate; wherein the trench includes an electrically conductive material that extends from the first side of the substrate to a depth of the trench; and wherein a length of the trench forms an overlapping spiral in the substrate.
Example 2 includes the inductor of example 1, wherein the trench is substantially perpendicular to the first side of the substrate.
Example 3 includes the inductor of example 1, wherein the substrate is a glass panel, glass wafer, or glass substrate.
Example 4 includes the inductor of example 1, wherein a width of the trench is 10 μm or the depth of the trench is at least 250 μm.
Example 5 includes the inductor of example 1, wherein the electrically conductive material is fully filled within the trench.
Example 6 includes the inductor of example 1, wherein the electrically conductive material is plated on a side of the trench.
Example 7 includes the inductor of example 1, further comprising traces electrically and physically coupled with the electrically conductive material at the first side of the substrate.
Example 8 includes the inductor of example 7, wherein the traces extend above the first side of the substrate.
Example 9 includes the inductor of example 1, wherein the trench extends from the first side of the substrate to the second side of the substrate.
Example 10 includes the inductor of example 9, further comprising traces that are electrically and physically coupled with the electrically conductive material at the second side of the substrate.
Example 11 includes an inductor, comprising: a substrate having a first side and a second side opposite the first side; a plurality of trenches extending from the first side of the substrate toward the second side of the substrate, the plurality of trenches being substantially parallel; wherein the plurality of trenches include an electrically conductive material that extends from the first side of the substrate to a depth, respectively, of the plurality of trenches; and wherein the plurality of trenches form an overlapping spiral in the substrate.
Example 12 includes the inductor of example 11, further comprising traces electrically and physically coupled with the electrically conductive material at the first side of the substrate.
Example 13 includes the inductor of example 11, wherein the substrate is a glass panel, glass wafer, or glass substrate.
Example 14 includes the inductor of example 11, wherein a width of the trench is 10 μm or the depth of the trench is at least 250 μm.
Example 15 includes the inductor of example 11, wherein at least one of the plurality of trenches extend from the first side of the substrate to the second side of the substrate.
Example 16 includes the inductor of example 11, further comprising traces that electrically and physically couple with the electrically conductive material in the plurality of trenches at the second side of the substrate.
Example 17 is a system, comprising: a device; an inductor electrically coupled with the device to provide power to the device, the inductor comprising: a glass substrate having a first side and a second side opposite the first side; a trench extending from the first side of the glass substrate toward the second side of the glass substrate; wherein the trench includes an electrically conductive material that extends from the first side of the glass substrate to a depth of the trench; and wherein the trench forms an overlapping spiral in the glass substrate.
Example 18 includes the system of example 17, wherein the electrically conductive material is a selected one of fully filled within the trench plated on a side of the trench.
Example 19 includes the system of example 17, further comprising traces electrically and physically coupled with the electrically conductive material at the first side of the substrate.
Example 20 includes the system of example 17, wherein the trench extends from the first side of the glass substrate to the second side of the glass substrate, and further comprising traces that are electrically and physically coupled with the electrically conductive material at the second side of the glass substrate.