Patent US5683944A successfully refreshed from Google Patents.
← Back to Patent Explorer
US5683944A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of fabricating a thermally enhanced lead frame

Assignee: NXP USA Inc
•
Filing: 1995-09-01
•
Granted: 1997-11-04
•
Expires: 2015-09-01
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract The device has a semiconductor die (18) mounted upon a downset X-shape die support (12) of a lead frame (10, 40). The lead frame also has tie bars (16) which are connected to the X-shape die support. Attached to the tie bars are thermal bars (14, 14') which are located between the semiconductor die and inner portion of the leads (20). The inner portion of the leads, the tie bars, and the thermal bars are offset from the plane occupied by the X-shape die support. The thermal bars aid in dissipating the heat from the die into the nearby lead tips so that the heat can be conducted out of the package body (30) through the thermally conductive lead frame. The semiconductor die is wire bonded to the inner portion of the leads. A package body (30) protects the die, the wire bonds (26), the thermal bars, and the inner portion of the leads.

Inventors

  • 👤 Bennett A. Joiner
  • 👤 Greg L. Ridsdale

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 14:16
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/411; H10W72/00; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; H10W72/07338; H10W72/07351; H10W72/07352; H10W72/30; H10W72/321; H10W72/851; H10W72/874; H10W72/884; H10W74/00; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49121

Claims Analysis

Total Claims: 14
Claim 1
Independent Claim 239 words
A method for making a semiconductor device, comprising the steps of: providing a lead frame having: a plurality of leads arranged around a centrally located cavity, the plurality of leads having an inner portion and an outer portion, and wherein the inner portion of the plurality of leads is disposed on a first plane; a plurality of tie bars; an X-shape die support which is attached to the plurality of tie bars, wherein the X-shape die support is disposed in the centrally located cavity on a second plane; and a thermal tab attached to one of the plurality of tie bars, wherein the thermal tab is substantially coplanar with the plurality of leads; mounting a semiconductor die onto the X-shape die support of the lead frame, wherein the semiconductor die is disposed in the centrally located cavity such that the thermal tab lies between an edge of the semiconductor die and the inner portion of the plurality of leads, and wherein the semiconductor die is mounted onto the X-shape die support such that the semiconductor die does not overlie the thermal tab and the semiconductor die does not contact the thermal tab; wire bonding the semiconductor die to the inner portion of the plurality of leads to form a plurality of wire bonds; and forming a package body around the semiconductor die, the plurality of wire bonds, the inner portion of the plurality of leads, and the thermal tab.
Claim 2
Independent Claim 239 words
A method for making a semiconductor device, comprising the steps of: providing a lead frame having: a plurality of leads arranged around a centrally located cavity, the plurality of leads having an inner portion and an outer portion, and wherein the inner portion of the plurality of leads is disposed on a first plane; a plurality of tie bars; an X-shape die support which is attached to the plurality of tie bars, wherein the X-shape die support is disposed in the centrally located cavity on a second plane; and a thermal tab attached to one of the plurality of tie bars, wherein the thermal tab is substantially coplanar with the plurality of leads; mounting a semiconductor die onto the X-shape die support of the lead frame, wherein the semiconductor die is disposed in the centrally located cavity such that the thermal tab lies between an edge of the semiconductor die and the inner portion of the plurality of leads, and wherein the semiconductor die is mounted onto the X-shape die support such that the semiconductor die does not overlie the thermal tab and the semiconductor die does not contact the thermal tab; wire bonding the semiconductor die to the inner portion of the plurality of leads to form a plurality of wire bonds; and forming a package body around the semiconductor die, the plurality of wire bonds, the inner portion of the plurality of leads, and the thermal tab.
Claim 3
Dependent Claim 18 words
The method of claim 1, wherein the step of providing the lead frame provides a copper lead frame.
Claim 4
Dependent Claim 31 words
The method of claim 1, wherein the step of mounting the semiconductor die mounts a die selected from a group consisting of a microprocessor and an application specific integrated circuit (ASIC).
Claim 5
Dependent Claim 16 words
The method of claim 1, wherein the step of wire bonding uses low loop wire bonding.
Claim 6
Dependent Claim 15 words
The method of claim 1, wherein the step of forming the package body comprises molding.
Claim 7
Independent Claim 285 words
A method for making a semiconductor device, comprising the steps of: providing a lead frame having: a plurality of leads arranged around a centrally located cavity, the plurality of leads having an inner portion and an outer portion, and wherein the inner portion of the plurality of leads is disposed on a first plane; a plurality of tie bars; an X-shape die support which is attached to the plurality of tie bars, wherein the X-shape die support is disposed in the centrally located cavity on a second plane; a thermal tab attached to one of the plurality of tie bars; and a die undertab extending from the thermal tab, such that the die undertab is disposed on a third plane mounting a semiconductor die onto the X-shape die support of the lead frame, wherein the semiconductor die is disposed in the centrally located cavity such that the thermal tab lies between an edge of the semiconductor die and the inner portion of the plurality of leads and the semiconductor die does not overlie the thermal tab and the semiconductor die does not contact the thermal tab, and wherein the semiconductor die is mounted onto the X-shape die support such that it overlies the die undertab: wire bonding the semiconductor die to the inner portion of the plurality of leads to form a plurality of wire bonds; and forming a package body around the semiconductor die, the plurality of wire bonds, the inner portion of the plurality of leads, the thermal tab, and the die undertab, wherein the package body is composed of a polymeric encapsulant such that a portion of the polymeric encapsulant lies between the die undertab and a backside of the semiconductor die.
Claim 8
Independent Claim 285 words
A method for making a semiconductor device, comprising the steps of: providing a lead frame having: a plurality of leads arranged around a centrally located cavity, the plurality of leads having an inner portion and an outer portion, and wherein the inner portion of the plurality of leads is disposed on a first plane; a plurality of tie bars; an X-shape die support which is attached to the plurality of tie bars, wherein the X-shape die support is disposed in the centrally located cavity on a second plane; a thermal tab attached to one of the plurality of tie bars; and a die undertab extending from the thermal tab, such that the die undertab is disposed on a third plane mounting a semiconductor die onto the X-shape die support of the lead frame, wherein the semiconductor die is disposed in the centrally located cavity such that the thermal tab lies between an edge of the semiconductor die and the inner portion of the plurality of leads and the semiconductor die does not overlie the thermal tab and the semiconductor die does not contact the thermal tab, and wherein the semiconductor die is mounted onto the X-shape die support such that it overlies the die undertab: wire bonding the semiconductor die to the inner portion of the plurality of leads to form a plurality of wire bonds; and forming a package body around the semiconductor die, the plurality of wire bonds, the inner portion of the plurality of leads, the thermal tab, and the die undertab, wherein the package body is composed of a polymeric encapsulant such that a portion of the polymeric encapsulant lies between the die undertab and a backside of the semiconductor die.
Claim 9
Dependent Claim 18 words
The method of claim 6, wherein the step of providing the lead frame provides a copper lead frame.
Claim 10
Dependent Claim 31 words
The method of claim 6, wherein the step of mounting the semiconductor die mounts a die selected from a group consisting of a microprocessor and an application specific integrated circuit (ASIC).
Claim 11
Dependent Claim 16 words
The method of claim 6, wherein the step of wire bonding uses low loop wire bonding.
Claim 12
Dependent Claim 15 words
The method of claim 6, wherein the step of forming the package body comprises molding.
Claim 13
Independent Claim 332 words
A method for making a semiconductor device, comprising the steps of: providing a lead frame having: a plurality of leads arranged around a centrally located cavity, the plurality of leads having an inner portion and an outer portion, and wherein the inner portion of the plurality of leads is disposed on a first plane; a plurality of tie bars; an X-shape die support which is attached to the plurality of tie bars, wherein the X-shape die support is disposed in the centrally located cavity on a second plane, wherein the plurality of tie bars is disposed on the first plane; a thermal tab attached to one of the plurality of tie bars, wherein the thermal tab is substantially coplanar with the plurality of tie bars; and a die undertab extending from the thermal tab located on the first plane such that the die undertab is disposed on a third plane; mounting a semiconductor die onto the X-shape die support of the lead frame, wherein the semiconductor die is disposed in the centrally located cavity such that the thermal tab lies between an edge of the semiconductor die and the inner portion of the plurality of leads and such that the thermal tab does not contact the semiconductor die but is positioned to conduct heat away from the semiconductor die into the plurality of leads through the inner portion of the plurality of leads, and wherein the semiconductor die is mounted onto the X-shape die support such that the semiconductor die does not overlie the thermal tab; wire bonding the semiconductor die to the inner portion of the plurality of leads to form a plurality of wire bonds; and forming a package body around the semiconductor die, the plurality of wire bonds, the inner portion of the plurality of leads, and the thermal tab, wherein the package body is composed of a polymeric encapsulant such that a portion of the polymeric encapsulant couples the die undertab to a backside of the semiconductor die.
Claim 14
Independent Claim 332 words
A method for making a semiconductor device, comprising the steps of: providing a lead frame having: a plurality of leads arranged around a centrally located cavity, the plurality of leads having an inner portion and an outer portion, and wherein the inner portion of the plurality of leads is disposed on a first plane; a plurality of tie bars; an X-shape die support which is attached to the plurality of tie bars, wherein the X-shape die support is disposed in the centrally located cavity on a second plane, wherein the plurality of tie bars is disposed on the first plane; a thermal tab attached to one of the plurality of tie bars, wherein the thermal tab is substantially coplanar with the plurality of tie bars; and a die undertab extending from the thermal tab located on the first plane such that the die undertab is disposed on a third plane; mounting a semiconductor die onto the X-shape die support of the lead frame, wherein the semiconductor die is disposed in the centrally located cavity such that the thermal tab lies between an edge of the semiconductor die and the inner portion of the plurality of leads and such that the thermal tab does not contact the semiconductor die but is positioned to conduct heat away from the semiconductor die into the plurality of leads through the inner portion of the plurality of leads, and wherein the semiconductor die is mounted onto the X-shape die support such that the semiconductor die does not overlie the thermal tab; wire bonding the semiconductor die to the inner portion of the plurality of leads to form a plurality of wire bonds; and forming a package body around the semiconductor die, the plurality of wire bonds, the inner portion of the plurality of leads, and the thermal tab, wherein the package body is composed of a polymeric encapsulant such that a portion of the polymeric encapsulant couples the die undertab to a backside of the semiconductor die.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2000-11-03 2001-05-05 2001-11-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-11-03 2005-05-05 2005-11-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-11-03 2009-05-05 2009-11-04 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag