Leadframe for die stacking applications and related die stacking concepts

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the inner die pad structure is spaced a distance below the lead finger inner portions and the outer die pad structure is coplanar with the lead finger inner portions.

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced a first distance below the lead finger inner portions and the inner die pad structure is spaced a second distance below the lead finger inner portions;
• the second distance being greater than the first distance.

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced a distance above the lead finger inner portions and the inner die pad structure is coplanar with the lead finger inner portions.

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the first and second chips are the same size.

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced above the lead finger inner portions and the inner die pad structure is spaced below the lead finger inner portions;
• the first and second chips and the lead finger inner portions each have respective upper and lower surfaces;
• the first chip connected to the lead finger inner portions by respective lower lead wires affixed to the lower surface of the first chip and the lower surfaces of the lead finger inner portions;
• and the second chip connected to the lead finger inner portions by respective upper lead wires affixed to the upper surface of the second chip and the upper surfaces of the lead finger inner portions.

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the inner die pad structure is spaced a distance above the lead finger inner portions and the outer die pad structure is spaced a distance below the lead finger inner portions.

A leadframe design, comprising:

• an inner die pad structure lying in a first plane;
• an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced above the lead finger inner portions and the inner die pad structure is spaced below the lead finger inner portions;
• the inner die pad structure, the first and second chips and the lead finger inner portions each have respective upper and lower surfaces;
• the first chip connected to the lead finger inner portions by respective lower lead wires affixed to the upper surface of the first chip and the upper surfaces of the lead finger inner portions;
• the second chip connected to the lead finger inner portions by respective upper lead wires affixed to the upper surface of the second chip and the upper surfaces of the lead finger inner portions;
• and the inner die pad structure connected to the lead finger inner portions by respective grounding lead wires affixed to the upper surface of the inner die pad structure and the upper surfaces of the lead finger inner portions.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the inner die pad structure is spaced a distance below the lead finger inner portions and the outer die pad structure is coplanar with the lead finger inner portions.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced a first distance below the lead finger inner portions and the inner die pad structure is spaced a second distance below the lead finger inner portions;
• the second distance being greater than the first distance.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being sup ported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced a distance above the lead finger inner portions and the inner die pad structure is coplanar with the lead finger inner portions.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the first and second chips are the same size.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced above the lead finger inner portions and the inner die pad structure is spaced below the lead finger inner portions;
• the first and second chips and the lead finger inner portions each have respective upper and lower surfaces;
• the first chip connected to the lead finger inner portions by respective lower lead wires affixed to the lower surface of the first chip and the lower surfaces of the lead finger inner portions;
• and the second chip connected to the lead finger inner portions by respective upper lead wires affixed to the upper surface of the second chip and the upper surfaces of the lead finger inner portions.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being supported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the inner die pad structure is spaced a distance above the lead finger inner portions and the outer die pad structure is spaced a distance below the lead finger inner portions.

A method of forming a leadframe design, comprising:

• providing an inner die pad structure lying in a first plane;
• providing an outer die pad structure lying in a second plane spaced apart from the inner die pad structure first plane and connected to the inner die pad by inner tie bars;
• providing an outer package surrounding at least the inner die pad structure and the inner tie bars;
• the outer die pad structure being su ported by outer tie bars;
• the outer package having outer walls;
• and
• providing lead fingers extending through the outer package outer walls;
• the lead fingers including an inner portions extending into the outer package proximate the inner and outer die pad structures;
• the inner portions of the lead fingers lying in a third plane;
• wherein at least one of the inner die pad structure first plane and the outer die pad structure second plane lie outside of the lead finger inner portions third plane and wherein a first chip is affixed to the inner die pad structure and a second chip is affixed to the outer die pad structure, and wherein the outer die pad structure is spaced above the lead finger inner portions and the inner die pad structure is spaced below the lead finger inner portions;
• the inner die pad structure, the first and second chips and the lead finger inner portions each have respective upper and lower surfaces;
• the first chip connected to the lead finger inner portions by respective lower lead wires affixed to the upper surface of the first chip and the upper surfaces of the lead finger inner portions;
• the second chip connected to the lead finger inner portions by respective upper lead wires affixed to the upper surface of the second chip and the upper surfaces of the lead finger inner portions;
• and the inner die pad structure connected to the lead finger inner portions by respective grounding lead wires affixed to the upper surface of the inner die pad structure and the upper surfaces of the lead finger inner portions.