US20170231113A1 - Heat sink with integrated threaded lid - Google Patents
Heat sink with integrated threaded lid Download PDFInfo
- Publication number
- US20170231113A1 US20170231113A1 US15/040,024 US201615040024A US2017231113A1 US 20170231113 A1 US20170231113 A1 US 20170231113A1 US 201615040024 A US201615040024 A US 201615040024A US 2017231113 A1 US2017231113 A1 US 2017231113A1
- Authority
- US
- United States
- Prior art keywords
- heat sink
- module lid
- threaded
- thread engagement
- die
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001816 cooling Methods 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 7
- 239000000853 adhesive Substances 0.000 description 7
- 230000001070 adhesive effect Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- 229910000679 solder Inorganic materials 0.000 description 3
- 239000004593 Epoxy Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
- H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/20009—Modifications to facilitate cooling, ventilating, or heating using a gaseous coolant in electronic enclosures
- H05K7/20136—Forced ventilation, e.g. by fans
- H05K7/20154—Heat dissipaters coupled to components
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/16—Constructional details or arrangements
- G06F1/20—Cooling means
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4871—Bases, plates or heatsinks
- H01L21/4882—Assembly of heatsink parts
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/367—Cooling facilitated by shape of device
- H01L23/3675—Cooling facilitated by shape of device characterised by the shape of the housing
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
- H05K1/0203—Cooling of mounted components
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2039—Modifications to facilitate cooling, ventilating, or heating characterised by the heat transfer by conduction from the heat generating element to a dissipating body
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
- H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
- H01L2023/4037—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws characterised by thermal path or place of attachment of heatsink
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
- H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
- H01L2023/4037—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws characterised by thermal path or place of attachment of heatsink
- H01L2023/4056—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws characterised by thermal path or place of attachment of heatsink heatsink to additional heatsink
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
- H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
- H01L2023/4037—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws characterised by thermal path or place of attachment of heatsink
- H01L2023/4062—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws characterised by thermal path or place of attachment of heatsink heatsink to or through board or cabinet
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
- H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
- H01L2023/4037—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws characterised by thermal path or place of attachment of heatsink
- H01L2023/4068—Heatconductors between device and heatsink, e.g. compliant heat-spreaders, heat-conducting bands
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
- H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
- H01L2023/4075—Mechanical elements
- H01L2023/4087—Mounting accessories, interposers, clamping or screwing parts
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/10—Bump connectors; Manufacturing methods related thereto
- H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
- H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
- H01L2224/161—Disposition
- H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
- H01L2224/16227—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation the bump connector connecting to a bond pad of the item
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
- H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
- H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
- H01L2224/321—Disposition
- H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/32245—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
- H01L2224/732—Location after the connecting process
- H01L2224/73251—Location after the connecting process on different surfaces
- H01L2224/73253—Bump and layer connectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
- H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L24/10—Bump connectors ; Manufacturing methods related thereto
- H01L24/15—Structure, shape, material or disposition of the bump connectors after the connecting process
- H01L24/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
- H01L24/73—Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/151—Die mounting substrate
- H01L2924/1517—Multilayer substrate
- H01L2924/15172—Fan-out arrangement of the internal vias
- H01L2924/15174—Fan-out arrangement of the internal vias in different layers of the multilayer substrate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/151—Die mounting substrate
- H01L2924/153—Connection portion
- H01L2924/1531—Connection portion the connection portion being formed only on the surface of the substrate opposite to the die mounting surface
- H01L2924/15311—Connection portion the connection portion being formed only on the surface of the substrate opposite to the die mounting surface being a ball array, e.g. BGA
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/161—Cap
- H01L2924/1615—Shape
- H01L2924/16152—Cap comprising a cavity for hosting the device, e.g. U-shaped cap
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/161—Cap
- H01L2924/162—Disposition
- H01L2924/16251—Connecting to an item not being a semiconductor or solid-state body, e.g. cap-to-substrate
Definitions
- the present disclosure relates to the field of electronic circuits, and specifically to cooling devices used in electronic circuits. Still more specifically, the present invention relates to heat sinks used as cooling devices in electronic circuits.
- a heat sink structure includes a heat sink; a threaded heat sink base pocket within the heat sink; a module lid, where the module lid thermally interfaces with a die; a threaded exterior portion of the module lid; and a thread engagement between the threaded heat sink base pocket and the threaded exterior portion of the module lid, where the thread engagement mechanically couples the heat sink to the module lid.
- a circuit board includes the heat sink structure described above.
- a computing device includes an air moving device and a circuit board that includes the heatsink structure described above.
- FIG. 1 depicts an exemplary computing device into which a novel heat sink structure is incorporated
- FIG. 2 illustrates a top view of the novel heat sink structure presented herein.
- FIG. 3 depicts a cross-sectional view of the heat sink structure shown in FIG. 2 .
- TIM thermal interface material
- mounting hardware used clips, screws, springs, etc. that provided tensions between the cooling solution (e.g., a heat sink) and the device being cooled (e.g., an integrated circuit (IC), also known as a “die”, which is a small block of semiconducting material on which a functional circuit is fabricated).
- the adhesive TIM provides thermal conduction between the heat sink and the die.
- mounting hardware takes up high quality board space and is sometimes impossible to use on various modules. That is, springs, clips, etc. not only take up space in a system, they are also difficult to manipulate.
- mounting hardware is not adjustable. That is, a clip/spring simply holds the heat sink down at a certain pressure, which is fixed. This results in undue pressure on connectors (between the die and a circuit board) as well as on the die itself.
- BGA ball grid array
- mounting hardware such as ball grid array (BGA) spring clips (used on modules to provide actuation to small heat sinks and used in conjunction with high performance TIMs) have the drawbacks of reduction in heat sink performance (due to poor mating between the heat sink and the die); solder ball stress/integrity issues (due to undue pressure against the die by the BGA spring clips); the inability to support high loads (due to the limited strength of the springs in the BGA spring clips); and the inability to survive shock/vibe requirements (due to the limited resilience provided by BGA spring clips).
- BGA ball grid array
- TIMs adhesive thermal interface materials
- glue glue
- Heat sink structure 103 includes a module lid 105 , which is mounted atop a die 107 (e.g., an integrated circuit), which is mounted atop a substrate 109 (e.g., a glass epoxy that supports internal wires to external connectors), which is mounted on a circuit board 111 (e.g. a glass epoxy structure that supports various integrated circuits, power supplies, fans, input/output interfaces, etc.).
- a die 107 e.g., an integrated circuit
- substrate 109 e.g., a glass epoxy that supports internal wires to external connectors
- a circuit board 111 e.g. a glass epoxy structure that supports various integrated circuits, power supplies, fans, input/output interfaces, etc.
- module lid 105 has a polygonal shape (e.g., a square) that has multiple threaded corners, such as threaded corner 113 .
- a heat sink shown in FIGS. 2-3 but not FIG. 1
- airflow 115 from an air moving device 117 e.g., a cooling fan within a housing of computing device 101 and/or mounted on the circuit board 111 itself
- FIGS. 2-3 Additional details of the heat sink structure 103 are shown below in FIGS. 2-3 .
- FIG. 2 a top view of the novel heat sink structure 103 introduced in FIG. 1 is presented.
- a heat sink 202 is mounted over the module lid 105 .
- Heat sink 202 has a threaded heat sink base pocket 204 , which is screwed onto the threaded corners (e.g., threaded corner 113 ) of module lid 105 to form multiple thread engagements (e.g., thread engagement 206 ).
- heat sink 202 is screwed down onto module lid 105 until 1) solid mechanical and thermal contact is established between heat sink 202 and module lid 105 , and 2) the airflow 115 from air moving device 117 flows unobstructed across the vanes (e.g., vane 208 ) on heat sink 202 .
- FIG. 3 a cross-sectional view of the heat sink structure 103 shown in FIG. 2 is presented.
- a package ball grid array (BGA) 301 provides electrical connections between a planar (i.e., a printed circuit board—not shown) and the die 107 using internal wiring, such as the depicted wire 303 that connects one of the solder balls from package BGA 301 to one or more of the solder balls in the chip BGA 305 .
- the chip BGA 305 is connected to internal circuitry (not shown) within the die 107 , which is thermally coupled by a die thermal interface material (TIM) 307 to the underside of the module lid 105 .
- TIM die thermal interface material
- module lid 105 is adhered to substrate 109 using a lid adhesive 311 (e.g., a heat resistant glue), thus providing a fixed combination of module lid 105 , die 107 , and substrate 109 .
- a lid adhesive 311 e.g., a heat resistant glue
- the present invention provides a novel and adjustable means for affixing the heat sink 202 to the module lid 105 . That is, the heat sink 202 has a threaded heat sink base pocket 204 , whose inner surfaces are threaded. These threaded inner surfaces from the threaded heat sink base pocket 204 screw onto the threaded corners (e.g., threaded corner 113 ) of the polygonal-shaped module lid 105 at areas such as the depicted thread engagement 206 area.
- the user is able to 1) selectively control the amount of pressure forced against the module lid 105 ; 2) evenly spread out the lid thermal interface material (TIM) 309 between the heat sink 202 and the module lid 105 by the rotational movement of the heat sink 202 ; and 3) align the orientation of the vanes (e.g., vane 208 ) such that airflow 115 from the air moving device 117 shown in FIGS. 1-2 flows between the vanes, thereby providing maximum heat removal.
- TIM lid thermal interface material
- the corners of a lidded module are rounded and threaded such that a heat sink with a certain-depth threaded recess can be screwed on.
- Mounting a heat sink in this fashion prevents the need for board level mounting hardware and allows the use of a high quality thermal interface material.
- the threading is aligned such that at an optimal, nominal gap, the fins and heat sink orientation are properly aligned with the airflow direction. Given the planarity of lidded modules, this type of actuation has a beneficial effect on the thermal bond line directly over the hottest components, further improving thermal performance of the heat sink.
- An additional benefit of the mounting scheme presented and described in the present disclosure and figures includes better electromagnetic interference (EMI) protection due to the intimate contact between the heat sink base and the module lid.
- EMI electromagnetic interference
- a threaded ring is used on the previously described heat sink structure to provide a compliant surface for mounting a standard heat sink. This type of mounting allows a spring clip or other constant force mounting scheme without using board space or impacting signal integrity.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Power Engineering (AREA)
- Computer Hardware Design (AREA)
- Theoretical Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Materials Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
- Thermal Sciences (AREA)
Abstract
Description
- The present disclosure relates to the field of electronic circuits, and specifically to cooling devices used in electronic circuits. Still more specifically, the present invention relates to heat sinks used as cooling devices in electronic circuits.
- In an embodiment of the present invention, a heat sink structure includes a heat sink; a threaded heat sink base pocket within the heat sink; a module lid, where the module lid thermally interfaces with a die; a threaded exterior portion of the module lid; and a thread engagement between the threaded heat sink base pocket and the threaded exterior portion of the module lid, where the thread engagement mechanically couples the heat sink to the module lid.
- In an embodiment of the present invention, a circuit board includes the heat sink structure described above.
- In an embodiment of the present invention, a computing device includes an air moving device and a circuit board that includes the heatsink structure described above.
-
FIG. 1 depicts an exemplary computing device into which a novel heat sink structure is incorporated; -
FIG. 2 illustrates a top view of the novel heat sink structure presented herein; and -
FIG. 3 depicts a cross-sectional view of the heat sink structure shown inFIG. 2 . - Electronics cooling for packaged modules often uses two methods of mounting/mating their cooling solution: mounting hardware and adhesive thermal interface material (TIM). In the prior art, mounting hardware used clips, screws, springs, etc. that provided tensions between the cooling solution (e.g., a heat sink) and the device being cooled (e.g., an integrated circuit (IC), also known as a “die”, which is a small block of semiconducting material on which a functional circuit is fabricated). The adhesive TIM provides thermal conduction between the heat sink and the die.
- Mounting hardware poses several problems.
- First, mounting hardware takes up high quality board space and is sometimes impossible to use on various modules. That is, springs, clips, etc. not only take up space in a system, they are also difficult to manipulate.
- Second, mounting hardware is not adjustable. That is, a clip/spring simply holds the heat sink down at a certain pressure, which is fixed. This results in undue pressure on connectors (between the die and a circuit board) as well as on the die itself.
- Third, mounting hardware such as ball grid array (BGA) spring clips (used on modules to provide actuation to small heat sinks and used in conjunction with high performance TIMs) have the drawbacks of reduction in heat sink performance (due to poor mating between the heat sink and the die); solder ball stress/integrity issues (due to undue pressure against the die by the BGA spring clips); the inability to support high loads (due to the limited strength of the springs in the BGA spring clips); and the inability to survive shock/vibe requirements (due to the limited resilience provided by BGA spring clips).
- Furthermore, adhesive thermal interface materials (TIMs), when used alone to adhere a heat sink to a die are among the lowest performers for thermal conductivity since they are mainly composed of polymer adhesive. Furthermore, adhesive TIMs are also extremely difficult to rework or remove, since they are an adhesive (glue) that permanently bonds the heat sink to the die.
- Other actuation hardware requires board space and sometimes holes in the board in order to have retention. This is the most undesirable option since board space near modules is at a premium and any hardware in these regions takes away from the capability and/or signal integrity of the whole system.
- With reference now to the figures, and specifically to
FIG. 1 , anexemplary computing device 101 into which the presently-presented and novelheat sink structure 103 is incorporated is presented.Heat sink structure 103 includes amodule lid 105, which is mounted atop a die 107 (e.g., an integrated circuit), which is mounted atop a substrate 109 (e.g., a glass epoxy that supports internal wires to external connectors), which is mounted on a circuit board 111 (e.g. a glass epoxy structure that supports various integrated circuits, power supplies, fans, input/output interfaces, etc.). - As shown in
FIG. 1 , in an embodiment of the presentinvention module lid 105 has a polygonal shape (e.g., a square) that has multiple threaded corners, such as threadedcorner 113. When a heat sink (shown inFIGS. 2-3 but notFIG. 1 ) is fully engaged with themodule lid 105,airflow 115 from an air moving device 117 (e.g., a cooling fan within a housing ofcomputing device 101 and/or mounted on thecircuit board 111 itself) flows parallel to (and thus unimpeded by) cooling vanes on the heat sink. Additional details of theheat sink structure 103 are shown below inFIGS. 2-3 . - With reference now to
FIG. 2 , a top view of the novelheat sink structure 103 introduced inFIG. 1 is presented. As shown inFIG. 2 , aheat sink 202 is mounted over themodule lid 105.Heat sink 202 has a threaded heatsink base pocket 204, which is screwed onto the threaded corners (e.g., threaded corner 113) ofmodule lid 105 to form multiple thread engagements (e.g., thread engagement 206). Thus,heat sink 202 is screwed down ontomodule lid 105 until 1) solid mechanical and thermal contact is established betweenheat sink 202 andmodule lid 105, and 2) theairflow 115 fromair moving device 117 flows unobstructed across the vanes (e.g., vane 208) onheat sink 202. - With reference now to
FIG. 3 , a cross-sectional view of theheat sink structure 103 shown inFIG. 2 is presented. - As shown in
FIG. 3 , a package ball grid array (BGA) 301 provides electrical connections between a planar (i.e., a printed circuit board—not shown) and thedie 107 using internal wiring, such as the depictedwire 303 that connects one of the solder balls frompackage BGA 301 to one or more of the solder balls in thechip BGA 305. Thechip BGA 305 is connected to internal circuitry (not shown) within the die 107, which is thermally coupled by a die thermal interface material (TIM) 307 to the underside of themodule lid 105. As depicted,module lid 105 is adhered tosubstrate 109 using a lid adhesive 311 (e.g., a heat resistant glue), thus providing a fixed combination ofmodule lid 105, die 107, andsubstrate 109. - The present invention provides a novel and adjustable means for affixing the
heat sink 202 to themodule lid 105. That is, theheat sink 202 has a threaded heatsink base pocket 204, whose inner surfaces are threaded. These threaded inner surfaces from the threaded heatsink base pocket 204 screw onto the threaded corners (e.g., threaded corner 113) of the polygonal-shaped module lid 105 at areas such as the depictedthread engagement 206 area. - As a user screws the
heat sink 202 down onto themodule lid 105, the user is able to 1) selectively control the amount of pressure forced against themodule lid 105; 2) evenly spread out the lid thermal interface material (TIM) 309 between theheat sink 202 and themodule lid 105 by the rotational movement of theheat sink 202; and 3) align the orientation of the vanes (e.g., vane 208) such thatairflow 115 from theair moving device 117 shown inFIGS. 1-2 flows between the vanes, thereby providing maximum heat removal. - Thus, as depicted and described herein, the corners of a lidded module are rounded and threaded such that a heat sink with a certain-depth threaded recess can be screwed on. Mounting a heat sink in this fashion prevents the need for board level mounting hardware and allows the use of a high quality thermal interface material. The threading is aligned such that at an optimal, nominal gap, the fins and heat sink orientation are properly aligned with the airflow direction. Given the planarity of lidded modules, this type of actuation has a beneficial effect on the thermal bond line directly over the hottest components, further improving thermal performance of the heat sink.
- An additional benefit of the mounting scheme presented and described in the present disclosure and figures includes better electromagnetic interference (EMI) protection due to the intimate contact between the heat sink base and the module lid.
- In an alternative embodiment of the present invention, a threaded ring is used on the previously described heat sink structure to provide a compliant surface for mounting a standard heat sink. This type of mounting allows a spring clip or other constant force mounting scheme without using board space or impacting signal integrity.
- Having thus described embodiments of the present invention of the present application in detail and by reference to illustrative embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the present invention defined in the appended claims.
Claims (9)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/040,024 US9736966B1 (en) | 2016-02-10 | 2016-02-10 | Heat sink with integrated threaded lid |
US15/076,986 US10002819B2 (en) | 2016-02-10 | 2016-03-22 | Heat sink with integrated threaded lid |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/040,024 US9736966B1 (en) | 2016-02-10 | 2016-02-10 | Heat sink with integrated threaded lid |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/076,986 Continuation US10002819B2 (en) | 2016-02-10 | 2016-03-22 | Heat sink with integrated threaded lid |
Publications (2)
Publication Number | Publication Date |
---|---|
US20170231113A1 true US20170231113A1 (en) | 2017-08-10 |
US9736966B1 US9736966B1 (en) | 2017-08-15 |
Family
ID=59497012
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/040,024 Active US9736966B1 (en) | 2016-02-10 | 2016-02-10 | Heat sink with integrated threaded lid |
US15/076,986 Active 2036-09-07 US10002819B2 (en) | 2016-02-10 | 2016-03-22 | Heat sink with integrated threaded lid |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/076,986 Active 2036-09-07 US10002819B2 (en) | 2016-02-10 | 2016-03-22 | Heat sink with integrated threaded lid |
Country Status (1)
Country | Link |
---|---|
US (2) | US9736966B1 (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170229374A1 (en) * | 2016-02-10 | 2017-08-10 | International Business Machines Corporation | Heat sink with integrated threaded lid |
US20180051940A1 (en) * | 2016-04-18 | 2018-02-22 | International Business Machines Corporation | Adjustable heat sink fin spacing |
CN109637988A (en) * | 2019-01-29 | 2019-04-16 | 西安微电子技术研究所 | A kind of low thermal resistance pressure controllable radiating box structure |
US10327356B2 (en) * | 2017-05-15 | 2019-06-18 | Fujitsu Limited | Electronic apparatus |
US20190189532A1 (en) * | 2017-12-15 | 2019-06-20 | Nokia Technologies Oy | Integrated circuit package and fastener |
US10785864B2 (en) * | 2017-09-21 | 2020-09-22 | Amazon Technologies, Inc. | Printed circuit board with heat sink |
CN112218453A (en) * | 2020-10-17 | 2021-01-12 | 张莲莲 | Household appliance Internet of things control device |
US10971836B2 (en) | 2017-11-14 | 2021-04-06 | Amazon Technologies, Inc. | Printed circuit board with embedded lateral connector |
CN112888271A (en) * | 2021-03-01 | 2021-06-01 | 蔡锐拓 | Optical transmitter and receiver structure for wired communication |
US11134591B2 (en) * | 2019-12-20 | 2021-09-28 | Astec International Limited | Circuit board assemblies for electronic devices |
US11262815B2 (en) * | 2019-11-01 | 2022-03-01 | Hewlett Packard Enterprise Development Lp | Heat sink system with broad compatibility capacity |
US20220375815A1 (en) * | 2020-12-28 | 2022-11-24 | Innoscience (Suzhou) Technology Co., Ltd. | Semiconductor Package and Method for Manufacturing the Same |
US11610832B2 (en) * | 2018-05-01 | 2023-03-21 | Semiconductor Components Industries, Llc | Heat transfer for power modules |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11222830B2 (en) * | 2018-01-03 | 2022-01-11 | Lenovo (Beijing) Co., Ltd. | Heat dissipation structure and electronic device |
US11121053B2 (en) * | 2020-01-17 | 2021-09-14 | Asia Vital Components (China) Co., Ltd. | Die heat dissipation structure |
Family Cites Families (43)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3229756A (en) * | 1964-01-21 | 1966-01-18 | Laszlo Z Keresztury | Semiconductor heat sink and/or cooler |
US4047198A (en) * | 1976-04-19 | 1977-09-06 | Hughes Aircraft Company | Transistor cooling by heat pipes having a wick of dielectric powder |
US4345267A (en) * | 1980-03-31 | 1982-08-17 | Amp Incorporated | Active device substrate connector having a heat sink |
US4396935A (en) * | 1980-10-06 | 1983-08-02 | Ncr Corporation | VLSI Packaging system |
US4607685A (en) * | 1984-07-06 | 1986-08-26 | Burroughs Corporation | Heat sink for integrated circuit package |
US4715438A (en) * | 1986-06-30 | 1987-12-29 | Unisys Corporation | Staggered radial-fin heat sink device for integrated circuit package |
US4918571A (en) * | 1987-03-31 | 1990-04-17 | Amp Incorporated | Chip carrier with energy storage means |
US5256902A (en) * | 1991-08-14 | 1993-10-26 | Vlsi Technology, Inc. | Metal heatsink attach system |
US5353193A (en) * | 1993-02-26 | 1994-10-04 | Lsi Logic Corporation | High power dissipating packages with matched heatspreader heatsink assemblies |
US5397919A (en) * | 1993-03-04 | 1995-03-14 | Square Head, Inc. | Heat sink assembly for solid state devices |
US5313099A (en) * | 1993-03-04 | 1994-05-17 | Square Head, Inc. | Heat sink assembly for solid state devices |
US5461766A (en) * | 1994-01-26 | 1995-10-31 | Sun Microsystems, Inc. | Method for integrally packaging an integrated circuit with a heat transfer apparatus |
US5566052A (en) * | 1995-06-08 | 1996-10-15 | Northern Telecom Limited | Electronic devices with electromagnetic radiation interference shields and heat sinks |
US5579827A (en) * | 1995-11-13 | 1996-12-03 | Us Micro Lab, Inc. | Heat sink arrangement for central processing unit |
US5708564A (en) * | 1996-05-07 | 1998-01-13 | Lin; Andy | Heat sink mounting structure |
US5789813A (en) * | 1996-09-30 | 1998-08-04 | Lsi Logic Corporation | Ball grid array package with inexpensive threaded secure locking mechanism to allow removal of a threaded heat sink therefrom |
US5774335A (en) * | 1997-04-08 | 1998-06-30 | Chip Coolers, Inc. | Heat sink assembly with height adjustable mounting clip |
US6021045A (en) * | 1998-10-26 | 2000-02-01 | Chip Coolers, Inc. | Heat sink assembly with threaded collar and multiple pressure capability |
US6252774B1 (en) * | 2000-03-28 | 2001-06-26 | Chip Coolers, Inc. | Multi-device heat sink assembly |
KR100375720B1 (en) * | 2000-10-09 | 2003-03-15 | 삼성전자주식회사 | Semiconductor package and method for manufacturing thereof |
US6343012B1 (en) * | 2000-11-13 | 2002-01-29 | Tyco Electronics Logistis Ag | Heat dissipation device with threaded fan module |
US6385044B1 (en) * | 2001-07-27 | 2002-05-07 | International Business Machines Corporation | Heat pipe heat sink assembly for cooling semiconductor chips |
US6549407B1 (en) * | 2001-12-27 | 2003-04-15 | Intel Corporation | Heat exchanger retention mechanism |
US6665187B1 (en) * | 2002-07-16 | 2003-12-16 | International Business Machines Corporation | Thermally enhanced lid for multichip modules |
US6695042B1 (en) * | 2002-07-31 | 2004-02-24 | Hewlett-Packard Development Company, L.P. | Adjustable pedestal thermal interface |
US6828673B2 (en) * | 2003-02-18 | 2004-12-07 | John Ficorilli | Heat sink assembly |
US20050034841A1 (en) | 2003-08-13 | 2005-02-17 | Barr Andrew Harvey | Integral chip lid and heat sink |
US6847106B1 (en) | 2003-10-01 | 2005-01-25 | Texas Instruments Incorporated | Semiconductor circuit with mechanically attached lid |
EP1548827A1 (en) | 2003-12-22 | 2005-06-29 | Telefonaktiebolaget LM Ericsson (publ) | Integrated circuit package arrangement and method |
US7161808B2 (en) * | 2004-03-19 | 2007-01-09 | Intel Corporation | Retaining heat sinks on printed circuit boards |
CN2706868Y (en) * | 2004-05-26 | 2005-06-29 | 鸿富锦精密工业(深圳)有限公司 | Radiating device combination |
US7486516B2 (en) * | 2005-08-11 | 2009-02-03 | International Business Machines Corporation | Mounting a heat sink in thermal contact with an electronic component |
US7905276B2 (en) * | 2006-02-09 | 2011-03-15 | Onscreen Technology, Inc. | Method and apparatus for leak-proof mounting of a liquid cooling device on an integrated circuit |
US7352575B2 (en) * | 2006-07-31 | 2008-04-01 | International Business Machines Corporation | Dynamic air moving system |
US8109321B2 (en) * | 2008-03-05 | 2012-02-07 | Alcatel Lucent | Modular heat sink assembly comprising a larger main heat sink member thermally connected to smaller additional floating heat sink members |
DE102008002160A1 (en) * | 2008-06-02 | 2009-12-03 | Robert Bosch Gmbh | Personal protective device for a vehicle and method for assembling a personal protective device for a vehicle |
TWM354219U (en) | 2008-08-26 | 2009-04-01 | Hon Hai Prec Ind Co Ltd | Electrical connector |
CN102938997A (en) * | 2011-08-16 | 2013-02-20 | 鸿富锦精密工业(深圳)有限公司 | Heat dissipation device |
US20140138811A1 (en) | 2012-11-21 | 2014-05-22 | Nvidia Corporation | A semiconductor device including a heat-spreading lid |
JP2014165231A (en) * | 2013-02-22 | 2014-09-08 | Fujitsu Ltd | Electronic component unit and fixing structure |
US10373891B2 (en) | 2013-06-14 | 2019-08-06 | Laird Technologies, Inc. | Methods for establishing thermal joints between heat spreaders or lids and heat sources |
JP6221499B2 (en) * | 2013-08-19 | 2017-11-01 | 富士通株式会社 | Electronic device and method of manufacturing electronic device |
US9736966B1 (en) * | 2016-02-10 | 2017-08-15 | International Business Machines Corporation | Heat sink with integrated threaded lid |
-
2016
- 2016-02-10 US US15/040,024 patent/US9736966B1/en active Active
- 2016-03-22 US US15/076,986 patent/US10002819B2/en active Active
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10002819B2 (en) * | 2016-02-10 | 2018-06-19 | International Business Machines Corporation | Heat sink with integrated threaded lid |
US20170229374A1 (en) * | 2016-02-10 | 2017-08-10 | International Business Machines Corporation | Heat sink with integrated threaded lid |
US10584924B2 (en) | 2016-04-18 | 2020-03-10 | International Business Machines Corporation | Adjustable heat sink fin spacing |
US20180051940A1 (en) * | 2016-04-18 | 2018-02-22 | International Business Machines Corporation | Adjustable heat sink fin spacing |
US10088244B2 (en) * | 2016-04-18 | 2018-10-02 | International Business Machines Corporation | Adjustable heat sink fin spacing |
US11035625B2 (en) | 2016-04-18 | 2021-06-15 | International Business Machines Corporation | Adjustable heat sink fin spacing |
US10948247B2 (en) | 2016-04-18 | 2021-03-16 | International Business Machines Corporation | Adjustable heat sink fin spacing |
US10327356B2 (en) * | 2017-05-15 | 2019-06-18 | Fujitsu Limited | Electronic apparatus |
US10785864B2 (en) * | 2017-09-21 | 2020-09-22 | Amazon Technologies, Inc. | Printed circuit board with heat sink |
US10971836B2 (en) | 2017-11-14 | 2021-04-06 | Amazon Technologies, Inc. | Printed circuit board with embedded lateral connector |
US20190189532A1 (en) * | 2017-12-15 | 2019-06-20 | Nokia Technologies Oy | Integrated circuit package and fastener |
US11610832B2 (en) * | 2018-05-01 | 2023-03-21 | Semiconductor Components Industries, Llc | Heat transfer for power modules |
CN109637988A (en) * | 2019-01-29 | 2019-04-16 | 西安微电子技术研究所 | A kind of low thermal resistance pressure controllable radiating box structure |
US11262815B2 (en) * | 2019-11-01 | 2022-03-01 | Hewlett Packard Enterprise Development Lp | Heat sink system with broad compatibility capacity |
US11134591B2 (en) * | 2019-12-20 | 2021-09-28 | Astec International Limited | Circuit board assemblies for electronic devices |
US11622476B2 (en) | 2019-12-20 | 2023-04-04 | Astec International Limited | Circuit board assemblies for electronic devices |
CN112218453A (en) * | 2020-10-17 | 2021-01-12 | 张莲莲 | Household appliance Internet of things control device |
US20220375815A1 (en) * | 2020-12-28 | 2022-11-24 | Innoscience (Suzhou) Technology Co., Ltd. | Semiconductor Package and Method for Manufacturing the Same |
US11830786B2 (en) * | 2020-12-28 | 2023-11-28 | Innoscience (Suzhou) Technology Co., Ltd. | Semiconductor package and method for manufacturing the same |
CN112888271A (en) * | 2021-03-01 | 2021-06-01 | 蔡锐拓 | Optical transmitter and receiver structure for wired communication |
Also Published As
Publication number | Publication date |
---|---|
US20170229374A1 (en) | 2017-08-10 |
US9736966B1 (en) | 2017-08-15 |
US10002819B2 (en) | 2018-06-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9736966B1 (en) | Heat sink with integrated threaded lid | |
US7782621B2 (en) | Circuit module and manufacturing method thereof | |
US7742299B2 (en) | Piezo fans for cooling an electronic device | |
US7474530B2 (en) | High-load even pressure heatsink loading for low-profile blade computer applications | |
US7388746B2 (en) | Heatsink assembly | |
US5969949A (en) | Interfitting heat sink and heat spreader slug | |
US7440282B2 (en) | Heat sink electronic package having compliant pedestal | |
US20080001277A1 (en) | Semiconductor package system and method of improving heat dissipation of a semiconductor package | |
US20070075412A1 (en) | Mid-plane arrangement for components in a computer system | |
US20090021918A1 (en) | Stacked heat-transfer interface structure | |
JPH07106477A (en) | Heat sink assembly with heat conduction board | |
KR100955936B1 (en) | Heat dissipation device for semiconductor package module and semiconductor package module having the same | |
KR20130094502A (en) | Semiconductor package and method for manufacturing the same | |
US20100271785A1 (en) | Heat-dissipating and fixing mechanism of electronic component and process for assembling same | |
US8422226B2 (en) | Heat dissipation device | |
US9230878B2 (en) | Integrated circuit package for heat dissipation | |
US9775229B1 (en) | Internally die-referenced thermal transfer plate | |
US7203065B1 (en) | Heatsink assembly | |
US20140321062A1 (en) | Heat sink | |
US20140252583A1 (en) | Power Semiconductor Assembly and Module | |
US20090315172A1 (en) | Semiconductor chip assembly | |
US20080057279A1 (en) | Laminated heat-transfer interface for cooler module | |
US11502020B2 (en) | Electronic device having a chip package module | |
JPH1168360A (en) | Cooling structure for semiconductor element | |
US7432591B1 (en) | Thermal enhanced plastic ball grid array with heat sink attachment option |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: INTERNATIONAL BUSINESS MACHINES CORPORATION, NEW Y Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ANDERL, WILLIAM J.;ELISON, BRET P.;MANN, PHILIP V.;SIGNING DATES FROM 20160129 TO 20160208;REEL/FRAME:037696/0458 |
|
AS | Assignment |
Owner name: INTERNATIONAL BUSINESS MACHINES CORPORATION, NEW Y Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE THIRD INVENTOR NAME PREVIOUSLY RECORDED AT REEL: 037696 FRAME: 0458. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNORS:ANDERL, WILLIAM J.;ELISON, BRET P.;MANN, PHILLIP V.;SIGNING DATES FROM 20160129 TO 20160208;REEL/FRAME:038194/0163 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 4 |