Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
2001-01-10
2002-10-08
Le, Vu A. (Department: 2824)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
C438S737000
Reexamination Certificate
active
06461892
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to microelectronic packaging and more particularly relates to methods of making connectors and packaged microelectronic components. In various microelectronic devices, it is desirable to provide a connection between two components, which can accommodate relative movement between the components. For example, where a semiconductor chip is mounted to a circuit board, thermal expansion and contraction of the chip and circuit board can cause the contacts on the chip to move relative to the corresponding electrically conductive features of the circuit board. This can occur during service and can also occur during manufacturing operations as, for example, during soldering operations on the circuit board.
As illustrated in certain preferred embodiments of commonly assigned U.S. Pat. No. 5,518,964 (“the '964 patent”), the disclosure of which is incorporated herein by reference, movable interconnections between elements such as a semiconductor chip and a substrate can be provided by first connecting leads between the elements and then moving the chip and the substrate away from one another through a predetermined displacement so as to bend the leads. For example, the substrate may be a connection component including a dielectric body and leads extending along a bottom surface of the dielectric body. The leads may have first or fixed ends permanently attached to the dielectric element and connected to electrically conductive features such as terminals, traces or the like on the dielectric body. The leads may also have second or releasable ends releasably attached to the dielectric body. The dielectric body, with the leads thereon, may be juxtaposed with the chip and the second ends of the leads may be bonded to contacts on the chip. Following bonding, the dielectric body and chip are moved away from one another, thereby bending the leads towards a vertically extensive disposition. During or after movement, a curable material such as a liquid composition may be introduced between the elements. The curable material is then cured such as by using heat, to form a compliant dielectric layer such as an elastomer or gel surrounding the leads. The resulting packaged semiconductor chip has terminals on the dielectric body or connection component which are electrically connected to the contacts on the chip but which can move relative to the chip so as to compensate for thermal effects. For example, the packaged chip may be mounted to a circuit board by solder-bonding the terminals to conductive features on the circuit board. Relative movement between the circuit board and the chip due to thermal effects is taken up in the moveable interconnection provided by the leads and the compliant layer.
Numerous variations of these processes and structures are disclosed in the '964 patent. For example, the package-forming process can be conducted on a wafer scale, so that the numerous semiconductor chips in a unitary wafer are connected to connection components in one sequence of operations. The resulting packaged wafer is then severed so as to provide individual units, each including one or more of the chips and portions of the dielectric body associated therewith. Also, the leads may be formed on the chip or wafer rather than on the dielectric body. In further embodiments, also disclosed in the '964 patent, a connector for use in making connections between two other microelectronic elements is fabricated by a generally similar process. For example, in one embodiment a dielectric body having terminals and leads as discussed above is connected to terminal structures on a temporary sheet. The temporary sheet and dielectric body are moved away from one another so as to bend the leads, and a liquid material is introduced around the leads and cured so as to form a compliant layer between the temporary sheet and the dielectric body. The temporary sheet is then removed, leaving the tip ends of the terminal structures projecting from a surface of the compliant layer. Such a component may be used, for example, by engaging it between two other components. For example, the terminal structures may be engaged with a semiconductor chip, whereas the terminals on the dielectric body may be engaged with a circuit panel or other microelectronic component.
Commonly assigned U.S. Pat. No. 6,117,694, the disclosure of which is incorporated herein by reference, teaches a microelectronic component, such as a connector or a packaged semiconductor device that is made by connecting multiple leads between a pair of elements and moving the elements away from one another so as to bend the leads toward a vertically extensive disposition. One of the elements includes a temporary support which is removed after the bending operation and after injecting and curing a dielectric material to form a dielectric layer surrounding and supporting the leads.
Despite the teachings of the '964 patent, the '649 patent, and the other advances in the art, there are still needs for further improvements in connection components and methods for making such connection components. Specifically, there is a need for a connection component whereby the flexible leads may be made without having to bond the lead and a method of making expandable, flexible linkages by using plating processes rather than joining processes.
SUMMARY OF THE INVENTION
One aspect of the present invention provides methods of making a component, such as a compliant connection component, having one or more leads. The leads may be flexible. One preferred method includes providing a removable or sacrificial layer having first and second surfaces and vias at spaced apart first locations of the removable layer. The vias may be formed using a broad array of processes including chemical etching processes and punching holes therein. The vias preferably extend from the first surface toward the second surface of the removable layer. The vias may be what are commonly referred to as “through vias” that extend from the first surface to the second surface of the removable layer. The vias may also be blind or partial vias that extend only part of the way between the first and second surfaces of the removable layer.
A conductive material, such as metal, may be deposited over the first surface of the removable layer and in each via to form one or more leads, each lead including a first end and a second end at a location remote from the first end of the lead. In certain embodiments, before the conductive material is deposited over the removable layer, the removable layer is placed atop the first surface of a substrate so that the first ends of the leads are connected to the substrate during the depositing a conductive material step. The conductive material deposited in the vias of the removable layer forms projections at the first ends of the leads extending downwardly into the removable layer. The projections are preferably connected with the substrate as they are formed. As a result, a separate bonding step is not required for reliably connecting the leads to the conductive metal sheet. This simplifies the process for making a connection component.
A dielectric layer may then be provided over the conductive material, such as by depositing the dielectric material over the conductive material. The removable layer may then be removed. After the removable material has been removed, the first and second ends of the flexible leads are preferably movable away from one another. For example, the second ends of the leads may be permanently attached to the dielectric layer while the first ends of the leads may be releasable and/or peelable from the dielectric layer. In preferred embodiments, a substrate, such as a conductive metal sheet including copper, is juxtaposed with the removable layer before the conductive material is deposited over the removable layer.
One preferred method of making a connection component having one or more flexible leads includes the steps of providing a removable layer having a first surface and a second su
Le Vu A.
Owens Beth E.
Tessera Inc.
LandOfFree
Methods of making a connection component using a removable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods of making a connection component using a removable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods of making a connection component using a removable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2996103