Method for package-on-package assembly with wire bonds to encapsulation surface

• US 9,349,706 B2
• Filed: 02/14/2013
• Issued: 05/24/2016
• Est. Priority Date: 02/24/2012
• Status: Active Grant

• Current Assignee: Adeia Semiconductor Technologies LLC (f/k/a Invensas Corporation) (Adeia Inc.)
• Original Assignee: Adeia Semiconductor Technologies LLC (f/k/a Invensas Corporation) (Adeia Inc.)
• Inventors: Co, Reynaldo, Mirkarimi, Laura
• Primary Examiner(s): TAYLOR, EARL N
• Application Number:
  US14/380,544
• Publication Number:
  US 20150017765A1
• Time in Patent Office: 1,195 Days
• Field of Search: 438/617, 219/56.22, 228/180.5
• US Class Current: 1/1
• CPC Class Codes: B23K 20/007 Ball bonding
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45014 Ribbon connectors, e.g. rectangular cross-section
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/45155 Nickel (Ni) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48145 the bodies being stacked
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4824 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/48247 : connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 : Fan-out arrangements
• CPC Class Codes: H01L 2224/73204 : the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73215 : Layer and wire connectors
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 2224/78301 : Capillary
• CPC Class Codes: H01L 2224/81801 : Soldering or alloying
• CPC Class Codes: H01L 2224/85 : using a wire connector
• CPC Class Codes: H01L 2225/06506 : Wire or wire-like electrical connections between devices
• CPC Class Codes: H01L 2225/0651 : Wire or wire-like electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06513 : Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 2225/06517 : Bump or bump-like direct electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06558 : the devices having passive surfaces facing each other, i.e. in a back-to-back arrangement
• CPC Class Codes: H01L 2225/06562 : at least one device in the stack being rotated or offset
• CPC Class Codes: H01L 2225/06565 : the devices having the same size and there being no auxiliary carrier between the devices
• CPC Class Codes: H01L 2225/06568 : the devices decreasing in size, e.g. pyramidical stack
• CPC Class Codes: H01L 2225/1023 : the support being an insulating substrate
• CPC Class Codes: H01L 2225/1041 : Special adaptations for top connections of the lowermost container, e.g. redistribution layer, integral interposer
• CPC Class Codes: H01L 2225/1052 : Wire or wire-like electrical connections
• CPC Class Codes: H01L 2225/1058 : Bump or bump-like electrical connections, e.g. balls, pillars, posts
• CPC Class Codes: H01L 23/3121 : a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/3171 : the coating being directly applied to the semiconductor body, e.g. passivation layer H01L23/3178 takes precedence
• CPC Class Codes: H01L 23/49517 : Additional leads
• CPC Class Codes: H01L 23/49811 : Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads H01L23/49827 takes precedence
• CPC Class Codes: H01L 23/5389 : the chips being integrally enclosed by the interconnect and support structures
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/49 : of a plurality of wire connectors
• CPC Class Codes: H01L 24/73 : 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
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 25/0655 : the devices being arranged next to each other
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 25/105 : the devices being of a type provided for in group H01L27/00
• CPC Class Codes: H01L 25/50 : Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/206 : Length ranges

Abstract

A microelectronic assembly (10) includes a substrate (12) having a first and second opposed surfaces. A microelectronic element (22) overlies the first surface and first electrically conductive elements (28) can be exposed at at least one of the first surface or second surfaces. Some of the first conductive elements (28) are electrically connected to the microelectronic element (22). Wire bonds (32) have bases (34) joined to the conductive elements (28) and end surfaces (38) remote from the substrate and the bases, each wire bond defining an edge surface (37) extending between the base and the end surface. An encapsulation layer (42) can extend from the first surface and fill spaces between the wire bonds, such that the wire bonds can be separated by the encapsulation layer. Unencapsulated portions of the wire bonds (32) are defined by at least portions of the end surfaces (38) of the wire bonds that are uncovered by the encapsulation layer (42).

Claims

1. A method of making a microelectronic assembly, comprising:

a) bonding a metal wire to a conductive element exposed at a first surface of a substrate, thereby forming a base of a wire bond on the conductive element;

b) extending a length of the metal wire through a capillary of a bonding tool;

c) cutting the metal wire within the capillary at a location between a clamped portion of the metal wire within the bonding tool and the base to at least partially define an end surface of the wire bond at a predetermined distance from the base of the wire bond;

d) forming an end portion at the end surface having a cross-section wider than a cross-section of the wire bond; and

e) forming a dielectric encapsulation layer overlying the first surface of the substrate and defining a major surface spaced apart from the first surface, wherein the encapsulation layer is formed so as to at least partially cover the first surface of the substrate and a portion of the wire bond, such that an unencapsulated portion of the wire bond is defined by a portion of the end portion,

wherein the wire bond has a first edge surface defined between the base and the end portion, the end portion has a second edge surface that extends outward from the first edge surface of the wire bond below the major surface of the dielectric encapsulation layer, and the dielectric encapsulation layer surrounds the second edge surface.

2. The method of claim 1, wherein the end portion has a substantially rounded configuration.

3. The method of claim 1, wherein the end portion has a ball shape.

4. The method of claim 1, wherein the cutting is performed before the forming of the end portion.