U.S. patent application number 12/171577 was filed with the patent office on 2008-11-06 for wedge-bonding of wires in electronic device manufacture with reversible wedge bonding.
This patent application is currently assigned to NXP B.V.. Invention is credited to ESTEBAN L. ABADILLA, CRISPULO LICTAO, ALEXANDER M. ROGADO, RAMIL N. VASQUEZ.
Application Number | 20080272176 12/171577 |
Document ID | / |
Family ID | 31979989 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080272176 |
Kind Code |
A1 |
VASQUEZ; RAMIL N. ; et
al. |
November 6, 2008 |
WEDGE-BONDING OF WIRES IN ELECTRONIC DEVICE MANUFACTURE WITH
REVERSIBLE WEDGE BONDING
Abstract
In the manufacture of electronic devices (22, 22'), e.g.
discrete semiconductor power devices or ICs, a reversible bonding
tool (10) is used having a bonding tip or wedge (1, 2) at each of
its opposite ends (11, 12). After extensive use of the wedge-tip
(1) at one end (11) for bonding wires (21), the tip (1) is worn
somewhat. Instead of needing to replace the bond tool as in the
prior art, the tool (10) in accordance with the invention is then
reversed to use the wedge-tip (2) at the opposite end (12) for
bonding further wires (20'). Thus, a cost saving is achieved with
regard to tool material.
Inventors: |
VASQUEZ; RAMIL N.; (CABUYAO
LAGUNA, PH) ; ABADILLA; ESTEBAN L.; (LAS PINAS CITY,
PH) ; ROGADO; ALEXANDER M.; (CAVITE, PH) ;
LICTAO; CRISPULO; (BINAN, PH) |
Correspondence
Address: |
NXP, B.V.;NXP INTELLECTUAL PROPERTY DEPARTMENT
M/S41-SJ, 1109 MCKAY DRIVE
SAN JOSE
CA
95131
US
|
Assignee: |
NXP B.V.
Eindhoven
NL
|
Family ID: |
31979989 |
Appl. No.: |
12/171577 |
Filed: |
July 11, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10525594 |
Feb 25, 2005 |
7413108 |
|
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PCT/IB2003/003580 |
Aug 7, 2003 |
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12171577 |
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Current U.S.
Class: |
228/1.1 |
Current CPC
Class: |
H01L 2924/01057
20130101; H01L 2924/01005 20130101; H01L 2224/78313 20130101; H01L
2924/01013 20130101; H01L 21/67138 20130101; H01L 2224/45144
20130101; H01L 2224/45144 20130101; H01L 2924/14 20130101; H01L
2924/01079 20130101; B23K 2101/40 20180801; H01L 2924/01074
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
228/1.1 |
International
Class: |
B23K 20/10 20060101
B23K020/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 28, 2002 |
GB |
0219910.7 |
Nov 6, 2002 |
EP |
0225811.9 |
Nov 6, 2002 |
GB |
0225811.9 |
Claims
1-3. (canceled)
4. A wire-bonding machine for ultrasonic wedge-bonding of wires in
the manufacture of electronic devices, wherein the machine includes
a reversible bonding tool having a wedge-bonding tip at opposite
ends of the tool, and a mount for coupling the tool to an
ultrasonic transducer, the mount allowing the tool to be reversed
so as to permit wire bonding using either the wedge-bonding tip at
one end or the wedge-bonding tip at the opposite end.
5. A wire-bonding machine according to claim 4, wherein the bonding
tool comprises a shank having the wedge-bonding tips at opposite
ends of the shank, and wherein the mount engages the tool at a
position on the shank between its opposite ends.
6. A reversible bonding tool for use in a machine according to
claim 4 wherein the tool comprises a shank having a wedge-bonding
tip at opposite ends of the shank.
7. A reversible bonding tool for use in a machine according to
claim 4 wherein the tool comprises a shank having at its opposite
ends a material which is different to that of the shank and which
provides a wedge-bonding tip at each of the opposite ends of the
shank.
8. A machine according to claim 4, wherein the wedge-bonding tips
at opposite ends are of tungsten carbide.
9. An electronic device including connections in the form of wires
which are wedge-bonded using the machine as recited in claim 4.
10. An electronic device including connections in the form of wires
which are wedge-bonded using the tool as recited in claim 6.
11. A wire-bonding machine for ultrasonic wedge-bonding of wires in
the manufacture of electronic devices, wherein the machine includes
a reversible bonding tool having a wedge-bonding tip at opposite
ends of the tool, wherein the bonding tool further comprises a
shank having the wedge-bonding tips at opposite ends of the shank,
a mount for coupling the tool to an ultrasonic transducer, the
mount allowing the tool to be reversed so as to permit wire bonding
using either the wedge-bonding tip at one end or the wedge-bonding
tip at the opposite end; and wherein the mount engages the tool at
a position on the shank between its opposite ends
12. The wire-bonding machine as recited in claim 11, wherein the
bonding tool comprises a shank having at its opposite ends a
material which is different to that of the shank and which provides
a wedge-bonding tip at each of the opposite ends of the shank.
13. The wire-bonding machine as recited in claim 12, wherein the
wedge-bonding tips at opposite ends are of tungsten carbide.
Description
[0001] This invention relates to the wedge-bonding of wires in the
manufacture of electronic devices. In particular, it relates to
wedge-bonding methods, machines and tools, and also to electronic
devices that include connections in the form of wires which are
wedge-bonded using such methods or machines or tools.
[0002] The wedge-bonding of wires is a well-established technology
that has been used for many decades to provide connections in
electronic devices. By way of example, the following is a selection
of recent United States patents on wedge bonding: U.S. Pat. No.
6,354,479, U.S. Pat. No. 6,135,341, U.S. Pat. No. 5,958,270, U.S.
Pat. No. 5,950,903, U.S. Pat. No. 5,945,065, U.S. Pat. No.
5,906,706, U.S. Pat. No. 5,836,071, U.S. Pat. No. 5,702,049, U.S.
Pat. No. 5,495,976, U.S. Pat. No. 5,452,838, U.S. Pat. No.
5,445,306, U.S. Pat. No. 5,364,004, U.S. Pat. No. 5,217,154, U.S.
Pat. No. 5,148,959, U.S. Pat. No. 5,018,658, and U.S. Pat. No.
5,007,576. The whole contents of these US patents are hereby
incorporated herein as reference material. The bonding tool
(typically of tungsten carbide) generally comprises a shank having
the wedge-bonding tip at one end.
[0003] There is always a desire for cost reduction. One of the many
items that involves an on-going cost is the need to periodically
replace the bond tool when its bonding tip is becoming worn through
use.
[0004] It is an aim of the present invention to reduce the cost of
replacing the bond tool.
[0005] According to one aspect of the invention, there is provided
a reversible bonding tool having a wedge-bonding tip at opposite
ends of the tool. Thus, the present invention provides a dual-tip
reversible tool, that increases the use time before replacement of
the tool is required. Thus, a saving can be achieved in tool
material.
[0006] According to another aspect of the invention, there are
provided wire-bonding machines having such a reversible bonding
tool in accordance with the present invention.
[0007] According to a further aspect of the invention, there are
provided wedge-bonding methods, wherein: [0008] a reversible
bonding tool in accordance with the present invention is used,
[0009] and, after using the tip at one end for bonding wires, the
tool is reversed to use the wedge-bonding tip at the opposite end
for bonding further wires.
[0010] According to yet another aspect of the invention, there are
provided electronic devices, for example an integrated circuit or a
power semiconductor device, that include connections in the form of
wires which are wedge-bonded using such a method or machine or tool
in accordance with the present invention.
[0011] Various advantageous features and feature-combinations in
accordance with the present invention are set out in the appended
Claims. These and others are illustrated in embodiments of the
invention that are now described, by way of example, with reference
to the accompanying diagrammatic drawings, in which:
[0012] FIGS. 1A and 1B are a schematic side-view of part of an
ultrasonic wedge-bonding machine in an embodiment of the present
invention, during use at successive times in the manufacture of
electronic devices;
[0013] FIG. 2A is a downward-looking perspective view of the
reversible bonding tool of FIG. 1, particularly of its working
ends, and showing a bonding tip at its upper end in accordance with
the invention; and
[0014] FIG. 2B is a upward-looking perspective view of the lower
working end of the bonding tool of FIG. 2, showing the bonding tip
at this lower end.
[0015] It should be noted that all the Figures are diagrammatic.
Relative dimensions and proportions of parts of these Figures have
been shown exaggerated or reduced in size, for the sake of clarity
and convenience in the drawings. The same reference signs are
generally used to refer to corresponding or similar features in
modified and different embodiments.
[0016] FIGS. 1A and 1B illustrate a wire-bonding stage in the
manufacture of electronic devices 20, 20', for example discrete
semiconductor power devices or semiconductor integrated circuits
(ICs). A reversible dual-tip bonding tool 10 is used having a
bonding tip (also termed "wedge") 1, 2 at each of the opposite ends
11, 12 of the tool, see FIG. 2A and 2B.
[0017] After extensive use of the wedge-bonding tip 1 at one end 11
for bonding wires 21 (as illustrated in FIG. 1A), the tip 1 is worn
somewhat. Instead of needing to replace the bond tool as in the
prior art, the tool 10 in accordance with the present invention is
then reversed to use the wedge-bonding tip 2 at the opposite end 12
for bonding further wires 21' (as illustrated in FIG. 1B). Thus, a
cost saving is achieved with regard to tool material.
[0018] Apart from using the reversible tool 10 in accordance with
the present invention, the wedge-bonding process and the
wire-bonding machine may be of known forms and so will not be
described in detail.
[0019] Thus, FIGS. 1A and 1B illustrate the work area of the
machine, where the device 20, 20' is placed on a work mount 32.
Wire 21, 21' is fed continually into this work area from a spool
(not shown). The wire 21, 21' is fed to a bond pad 23, 23' of the
device 20, 20', and it is pressed against the bond pad 23, 23' by
the lower working end (11 in FIG. 1A; 12 in FIG. 1B) of the tool
10. The wire 21, 21' may comprise aluminium (typically an Al alloy)
for both discrete power devices and for ICs, and the bond pad 23,
23' may also comprise aluminium. In some devices, it may be
preferred to use gold wire 21, 21'. The wire 21, 21' forms
electrical connections between, for example, the bond pad 23, 23'
and terminal leads of the device package (not shown).
[0020] While being pressed against the bond pad 23, 23', the wire
21, 21' is bonded to the pad 23, 23' by turning on an ultrasonic
source to a transducer 30 that applies ultrasonic energy to the
wire 21, 21' on the pad 23, 23' via the respective bonding tip 1 or
2 of the tool 10. FIGS. 1A and 1B schematically show the tool 10
mounted in a horn of the transducer 30. The horn can be of known
form coupled to the source (not shown) of the ultrasonic
energy.
[0021] In the embodiment illustrated in FIGS. 1A and 1B, the bond
tool 10 comprises a shank, with tapered work ends 11 and 12 at the
opposite ends of the shank. Narrow bonding tips 1 and 2 (which
engage with the wire 21, 21' to be bonded) are present at these
work ends, specific embodiments being shown in FIGS. 2A and 2B. In
the interests of simplicity of drawing, the taper is not shown in
FIGS. 2A and 2B.
[0022] There are a variety of known geometries and structures that
may be adopted for the work end and wedge tip. FIGS. 1A, 1B, 2A and
2B illustrate a very simple grooved structure for the tips 1, 2 at
the opposite working ends 11, 12, formed integral with the shank.
In this case, the entire bonding tool 10 (its shank, its ends and
its tips) may be of tungsten carbide. The single groove illustrated
for each tip 1 and 2 in FIGS. 2A and 2B serves for retaining the
wire in position against the bond pad during the ultrasonic
bonding. In more complex tip designs, cross-grooves and/or
protrusions may also be included.
[0023] FIGS. 1A and 1B do not show any detail of the wire-bonding
machine in respect of the mounting of the tool 10 in the transducer
horn 30. This mount 31 couples the tool 10 ultrasonically to the
transducer in known manner. However, the form of the mount 31 and
the tool shank are such as to allow the tool 10 to be reversed in
the mount 31, so as to permit wire bonding using either the
wedge-bonding tip 1 at one end 11 (FIG. 1A) or the wedge-bonding
tip 2 at the opposite end 12 (FIG. 1B).
[0024] This reversible mount aspect is most readily achievable when
the mount 31 engages the shank of the tool 10 at a position in
between its opposite ends 11, 12. In the embodiment illustrated in
FIGS. 1A and 1B, there is a different mount position on the tool
shank when the respective ends 11 and 12 are used, but the shank is
of the same (i.e. uniform) cross-section along at least the
length(s) where these mount positions are present.
[0025] The drawings have shown only a very simple basic form for
the tool and a schematic representation of the machine and of the
bonding process. It will be apparent to persons skilled in the art
that this basic form can be extended, embellished and modified with
the type of features that are commonly used or sometimes used in
the art.
[0026] Thus, for example, FIG. 1 does not show how the wire 21, 21'
may be guided and fed to the device bond pad 23, 23'. A guide that
is external to the bond tool 10 may be used close to the working
tip 1, 2 when the tool 10 has the very simple structure illustrated
in FIGS. 1 and 2. In other embodiments, a guide hole for the wire
may be present in the bond tool 10. Thus, for example, separate
guide holes (providing a through passage for the wire 21, 21') may
extend obliquely through each end 11, 12 of the tool 10, or there
may be a single feed hole (in the form of a capillary bore) that
extends through the length of the tool 10.
[0027] In the embodiment described above, the whole bond tool 10 is
composed of tungsten carbide. However, other embodiments may use
other materials, for example, using hardened steel for the shank or
titanium carbide for the shank.
[0028] Different known materials may be used for different parts of
the tool 10 (the shank, the work ends 11 and 12, and the bonding
tips 1 and 2), both bulk materials and coatings. The shank itself
may be formed of a relatively hard, stiff material having a high
modulus of elasticity (such as tungsten carbide, hardened steel, or
titanium carbide), whereas other materials that are hard,
precision-shaped and more abrasion resistant may be used at its
opposite ends 11 and 12. Thus, for example, the bonding tips 1 and
2 themselves may comprise a ceramic material or another, more
expensive material such as diamond or osmium.
[0029] From reading the present disclosure, many other variations
and modifications will be apparent to persons skilled in the art.
Such variations and modifications may involve equivalent and other
features which are already known in the design, manufacture and use
of wedge-bonding tools and machines and of electronic devices
having wedge-bonded wires, and which may be used instead of or in
addition to features already described herein. Examples of such
features are to be found in the US patents cited herein previously
as reference material.
[0030] Although Claims have been formulated in this Application to
particular combinations of features, it should be understood that
the scope of the disclosure of the present invention also includes
any novel feature or any novel combination of features disclosed
herein either explicitly or implicitly or any generalisation
thereof, whether or not it relates to the same invention as
presently claimed in any Claim and whether or not it mitigates any
or all of the same technical problems as does the present
invention.
[0031] The Applicants hereby give notice that new Claims may be
formulated to such features and/or combinations of such features
during the prosecution of the present Application or of any further
Application derived therefrom.
* * * * *