This disclosure relates to heat sinks, and more particularly, to methods of heat sinking components mounted on printed boards.
Solid state drives (SSDs) store information using solid state memory devices, such as flash memory devices. In order to achieve performance targets (e.g., data transfer rates), SSDs may utilize a plurality of flash memory devices electrically connected to a controller using a plurality of data channels. Read and write speeds to and from the flash memory devices may be affected by the number of data channels and the frequencies at which the controller and flash memory devices operate. Increasing the frequencies of the controller and flash memory devices may increase an amount of heat generated by the controller and the individual flash memory devices, other factors, such as process node and transistor type, being equal. Further, increasing the number of flash memory devices in a SSD may increase the total amount of heat generated, other factors, such as process node, transistor type, and operating frequency, being equal.
In some examples, the disclosure describes a method including coupling a printed board assembly (PBA) to a fixture. In some examples, the PBA may include a printed board (PB) and a plurality of components electrically and mechanically coupled to the PB, and each component of the plurality of components may define a respective surface. The method may further include planarizing at least one of the respective surfaces of the plurality of components using an abrasive tool. The method may further include attaching a heat sink to the respective surfaces of the plurality of components.
In some examples, the disclosure describes a system including a fixture configured to restrain a PBA and an abrasive tool. In accordance with these examples, the PBA may include a PB and a plurality of components electrically and mechanically coupled to the PB, and each component of the plurality of components may define a respective surface. At least one of the fixture or the abrasive tool may be configured to be moved relative to the other of the abrasive tool or the fixture to planarize at least one of the respective surfaces of the plurality of components such that the respective surfaces of the plurality of components lie in a substantially flat plane after planarization.
In some examples, the disclosure describes a system including means for restraining a PBA. The may include a PB and a plurality of components electrically and mechanically coupled to the PB, and each component of the plurality of components may define a respective surface. In accordance with these examples, the system also may include means for planarizing at least one of the respective surfaces of the plurality of components such that the respective surfaces of the plurality of components lie in a substantially flat plane after planarization.
The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.
The disclosure describes techniques and systems for planarizing a surface of at least one component mounted to a printed board (PB) to facilitate coupling of a heat sink to the at least one component. Printed board assemblies (PBAs) include a PB and a plurality of components. In some examples, the components may include a plurality of active devices, such as controllers, flash memory devices, buffer memory devices, or the like. The techniques and systems may planarize the at least some respective surfaces of the components to facilitate coupling of a single heat sink to at least one of the components. In this way, the techniques and systems may facilitate assembly of a PBA and a heat sink, compared to requiring a separate heat sink for each component to be heat-sinked.
In some examples, a system for planarizing a plurality of components mounted to a PB may include a fixture and an abrasive tool. The fixture may be configured to hold or restrain the PB, and may include a material or shape that facilitates holding the PB substantially flat (planar) during the planarization technique. In some examples, a compliant film may be disposed between a rigid support of the fixture and the PB assembly. The compliant film may conform to non-planar features on a back side of the PB, such as solder bumps, while allowing the rigid fixture to hold the PB substantially planar during the planarization technique.
The abrasive tool may include any tool that defines a substantially planar surface and includes or utilizes an abrasive material to abrade material from a respective surface of one or more of the plurality of components to result in the respective surfaces lying in a substantially flat plane after the planarization technique. This may facilitate formation of a substantially uniform planar surface for attaching a heat sink to a plurality of components of the PBA. A substantially uniform planar surface for multiple components may facilitate more efficient assembly of the PBA and one or more heat sinks, while allowing sufficient thermal contact between the components and the heat sink. Similarly, the substantially uniform planar surface for multiple components may improve thermal contact between respective surfaces of the multiple components and the heat sink compared to instances where multiple components do not include the substantially uniform planar surface.
Planarizing respective surfaces for multiple components to lie in substantially the same plane may be facilitated by performing the planarization after the components are attached to the PB compared to individually planarizing surfaces prior to attaching the components to the PB. For example, the PB may not lie substantially in a plane, such that, even if the individual surfaces of the components are substantially planar, after connecting the components to the PB, the component surfaces may not lie in a substantially flat plane. Planarizing the respective surfaces after the components are attached to the PB also may result in the component surfaces lying in a substantially flat plane, even if the PB does not lie substantially in a plane.
In some examples, PBA 100 may be part of a solid state drive (SSD) (e.g., SSD 200,
PB 102 includes a plurality of surfaces, including a first PB surface 106A and a second PB surface 106B. First PB surface 106A may be substantially opposite to and substantially parallel to second PB surface 106B. First and second PB surfaces 106A and 106B may be the major (e.g., largest) surfaces of PB 102. In some examples, the plurality of components 104 may be attached to first PB surface 106A, to second PB surface 106B, or both. As illustrated in
In some examples, one or both of first PB surface 106A and second PB surface 106B may include surface features, non-uniformities, or non-planarity. In some examples, the surface features or non-uniformities may include solder bumps from soldering components 104 to PB 102, e.g., in through-hole mounting techniques. In some examples, the surface features or non-uniformities additionally or alternatively may include one or more components 104 attached to the respective PB surface 106A or 106B. For example, second PB surface 106B may include one or more passive or active components, one or more solder bumps, curvature such that second PB surface 106B is not substantially planar, or the like. As illustrated in
In some examples, one or more surfaces of at least one of components 104 may include surface non-uniformities. Each component 104 includes a respective first component surface 108A proximate to PB 102 and a respective second component surface 108B opposite of first component surface 108A and PB 102. In some examples, at least one of the respective second component surfaces 108B includes one or more surface non-uniformities, such as surface roughness or curvature that deviates from planarity. Surface non-uniformities of second component surfaces 108B may hinder thermal coupling between second component surfaces 108B and a heat sink thermally coupled to components 104.
In accordance with one or more examples of the disclosure, a system that includes a fixture 114 and an abrasive tool 120 may be used to substantially remove surface non-uniformities from one or more of second component surfaces 108B of components 104. Fixture 114 may be configured to restrain or hold PBA 100, e.g., during the planarization technique. In some examples, fixture 114 also may be configured to maintain PB 102 substantially planar when PBA 100 is restrained by fixture 114. In this way, fixture 114 may be configured to maintain components 104 substantially motionless relative to each other during the planarization technique.
In some examples, fixture 114 may include a substantially rigid support 118 and a compliant film 110. Substantially rigid support 118 may include a substantially rigid material, which may exhibit substantially no deformation (e.g., no deformation or nearly no deformation) under the forces exerted on substantially rigid support 118 during the planarization techniques described herein. Example materials from which substantially rigid support 118 may be formed include wood, metal, an alloy, a polymer or mixture of polymers, or the like.
In some examples, compliant film 110 may be disposed between PBA 100 and substantially rigid support 118. For example, as shown in
Compliant film 110 may include flexible and conforming material. For example, compliant film 110 may deform in response to contact with surface features, non-uniformities, or non-planarity of first PB surface 106A when PBA 100 is pressed against compliant film 110 during planarization of second component surfaces 108B. The material(s) from which compliant film 110 is formed may be selected to be sufficiently flexible to deform in response to contact with first PB surface 106A while being sufficiently resilient to exert a force against first PB surface 106A during the planarization technique. For example, compliant film 110 may be sufficiently inflexible that none of the surface features, non-uniformities, or non-planar portions of first PBA surface 106A contact substantially rigid support 118 during the planarization technique.
In some examples, compliant film 110 may possess adhesive properties, such that compliant film 110 at least partially restrains PBA 100 with respect to substantially rigid support 118. Compliant film 110 may be made of any suitable flexible material, including, wax, a foam tape, a polyurethane, or the like.
In other examples, instead of including compliant film 110, fixture 114 may include alternative mechanisms to support PBA 100 and, optionally, restrain PBA 100 relative to fixture 114. For example, fixture 114 may include a plurality of pillars or protrusions that extend from fixture surface 116A. The pillars or protrusions may be located at selected locations of fixture surface 116A such that the pillars or protrusions contact first PB surface 106A of PB and do not contact any components 104 that are attached to first PB surface 106A. Additionally, the pillars or protrusions may be sized such that any components 104 attached to first PB surface 106A do not contact fixture surface 116A when PBA 100 is pressed against the pillars or protrusions during the planarization technique.
As another example, fixture surface 116A may define a complementary shape to first PB surface 106A of PBA 100. In other words, fixture surface 116A may define a topology that is opposite to the surface topology of first PB surface 106A, such that the surface features of the first PB surface 106A substantially fit within the topology of fixture surface 116A and second PB surface 106B is maintained as a substantially flat plane during the planarization technique.
In some examples, fixture 114 may include one or more restraining devices, such as clamps, fasteners, clips, or the like. The one or more restraining devices may restrain PBA 100 relative to fixture 114 during the planarization technique. In some examples, the one or more restraining devices restrain movement of PBA 100 relative to fixture 114 in one or more of the x-, y-, and z-axes (where orthogonal x-y-z axes are shown in
The system also may include an abrasive tool 120. Abrasive tool 120 may define a substantially planar surface, such that abrasive tool 120 facilitated planarizing one or more of second component surfaces 108B. In some examples, abrasive tool 120 includes an abrasive film or layer, such as a lapping film 122, attached to a substantially rigid, substantially planar plate 124, as shown in
In other examples, as shown in
The apparatus or device including abrasive tool 120 and fixture 114 may be used to reduce or substantially remove the surface non-uniformities of second component surfaces 108B of components 104 to result in second component surfaces 108B being disposed along a substantially flat plane. In some examples, one or both of abrasive tool 120 (e.g., substantially planar plate 124 or 128) or fixture 114 is configured to move relative to the other of abrasive tool 120 or fixture 114. In other examples, both abrasive tool 120 and fixture 114 are configured to move relative to one another.
As abrasive tool 120 moves relative to PBA 100, lapping film 122 or abrasive slurry 126 moves over the respective second component surfaces 108B of a plurality of components 104 and planarizes one or more of the respective second component surfaces 108B of the plurality of components 104. In some examples, abrasive tool 120 may be applied to individual components 104 to reduce or remove surface non-uniformities of that individual component. However, in some examples, abrasive tool 120 may be simultaneously or sequentially applied to the respective second component surfaces 108B of a plurality of electrical components 104, such that the plurality of electrical components 104 are polished or planarized as part of the same process. Not only may this be more efficient, this may facilitate formation of a substantially planar surface across multiple second component surfaces 108B.
By planarizing multiple second component surfaces 108B to lie in the same plane, a single heat sink may be thermally coupled to multiple (e.g., at least two) second component surfaces 108B while having desirable thermal contact between the heat sink and the respective second component surfaces 108B. This may allow simpler and/or faster assembly of PBA 100 with a heat sink compared to using a respective heat sink for each respective component of the plurality of components 104. Similarly, the substantially uniform planar surface for multiple components may improve thermal contact between respective surfaces of the multiple components and the heat sink compared to instances where multiple components do not include the substantially uniform planar surface.
Planarizing multiple second component surfaces 108B to lie in the same plane may be facilitated by performing the planarization after components 104 are attached to PB 102 compared to individually planarizing second components surfaces 108B prior to attaching components 104 to PB 102. For example, PB 102 may not lie substantially in a plane, such that, even if second component surfaces 108B are individually substantially planar, after connecting components 104 to PB 102, second component surfaces 108B may not lie in a substantially flat plane. Planarizing the respective second component surfaces 108B after components 104 are attached to PB 102 also may result in the respective second component surfaces 108B lying in a substantially flat plane, even if PB 102 does not lie substantially in a plane.
Although three components 104 are illustrated in
SSD 200 also includes at least one heat sink 202. In some examples, a single heat sink 202 may be thermally coupled to all of components 104. In other examples, heat sink 202 may be thermally coupled to a subset of components 104. In some examples, SSD 200 may include a plurality of heat sinks 202, each of which may be coupled to at least two components 104.
In some examples, heat sink 202 may be thermally coupled to the at least two components 104 using a thermal interface material such as thermal paste, a thermal adhesive, a thermal tape, or the like. In some examples, heat sink 202 may be mechanically coupled to at least PB 102 using clips, pins, compression springs, or other similar devices to retain heat sink 202 relative to PB 102 and components 104.
Heat sink 202 may include a thermally conductive material such as aluminum, copper, or the like. Heat sink 202 may be configured to transfer heat generated by components 104 to cool components 104. For example, heat sink 202 may have greater thermal mass than components 104, may have greater volume than components 104, may include geometric features such as fins that facilitate increased heat transfer, or may be thermally coupled to another component to which the heat may be transferred. In this way, heat sink 202 may facilitate cooling of components 104. Heat sink 202 may be passive cooled, actively cooled, or both. Passive cooling may include conduction of heat to another component, such as housing 204, passive convection, radiation, or the like. Active cooling may include forced air convection, liquid cooling using a pumped fluid, or the like.
SSD 200 also includes housing 204. Housing 204 may include a plurality of sides and defines an internal volume in which PBA 100 and heat sink 202 are disposed. In some examples, housing 204 may include a thermally conductive material, such as a metal, an alloy, a thermally conductive ceramic, a thermally conductive polymer or polymer doped to be thermally conductive, or the like. In some examples, heat sink 202 may be thermally coupled to housing 204 by a thermal interface material such as a thermal paste, a thermal adhesive, a thermal tape, or the like. In some examples, housing 204 may act as an extension of heat sink 202 to further dissipate heat from components 104.
Housing 204 may include one of several sizes, and may conform to one or various size standards for SSDs. In some examples, housing 204 may be sized as a 1.8 inch, 2.5 inch, or 3.5 inch form factor. However, in general, housing 204 may be any size.
In some examples, the technique may include coupling PBA 100 to fixture 114 (402). As described in
In some examples, coupling PBA 100 to fixture 114 (402) may include alternative or additional mechanisms to support PBA 100 and, optionally, restrain PBA 100 relative to fixture 114. For example, fixture 114 may include a plurality of pillars or protrusions that extend from fixture surface 116A. The pillars or protrusions may be located at selected locations of fixture surface 116A such that the pillars or protrusions contact first PB surface 106A of PB 102 and do not contact any components 104 that are attached to first PB surface 106A.
In other examples, coupling PBA 100 to fixture 114 (402) may include positioning a first PB surface 106A of PBA 100 directly on fixture surface 116A. Fixture surface 116A may define a complementary shape to first PB surface 106A of PBA 100. In other words, fixture surface 116A may define a topology that is opposite to the surface topology of first PB surface 106A, such that the surface features of the first PB surface 106A substantially fit within the topology of fixture surface 116A and second PB surface 106B is maintained as a substantially flat plane during the planarization technique. Thus, PBA 100 may fit directly within fixture 114.
In some examples, fixture 114 may include one or more restraining devices, such as clamps, fasteners, clips, or the like. The one or more restraining devices may restrain PBA 100 relative to fixture 114 during the planarization technique. In some examples, the one or more restraining devices restrain movement of PBA 100 relative to fixture 114 in one or more of the x-, y-, and z-axes (where orthogonal x-y-z axes are shown in
After PBA 100 has been coupled to fixture 114 (402), at least one surface of at least one component 104 may be planarized using abrasive tool 120 (404). In some examples, abrasive tool 120 may include an abrasive film or layer, such as a lapping film 122, attached to a substantially rigid, substantially planar plate 124, as shown and described in
In some examples, planarizing the respective surfaces of the plurality of components 104 (404) involves moving one or both of abrasive tool 120 or fixture 114 relative to the other of abrasive tool 120 or fixture 114. As abrasive tool 120 moves relative to PBA 100 or vice versa, lapping film 122 or abrasive slurry 126 moves over the respective second component surfaces 108B of plurality of components 104 and planarizes the respective second component surfaces 108B of the plurality of components 104. The planarization of multiple components 104 using fixture 114 and abrasive tool 120 may be performed on all of components 104 or a subset of components 104. In some examples, abrasive tool 120 may be applied to individual components 104 to reduce or remove surface non-uniformities of that individual component. However, in some examples, abrasive tool 120 may be simultaneously or sequentially applied to the respective second component surfaces 108B of a plurality of components 104, such that the plurality of components 104 are polished or planarized as part of the same process. Not only may this be more efficient, this may facilitate formation of a substantially planar surface across multiple second component surfaces 108B.
After planarization, in some examples, the technique of
In some examples, the technique of
Various examples have been described. These and other examples are within the scope of the following claims.
This application is a continuation application of co-pending U.S. patent application Ser. No. 14/487,922, filed on Sep. 16, 2014, which is incorporated herein by reference.
Number | Date | Country | |
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Parent | 14487922 | Sep 2014 | US |
Child | 15696614 | US |