ASTM F72-95

Standard Specification for Gold Wire for Semiconductor Lead Bonding

SCOPE
1.1 This specification covers round drawn/extruded gold wire for internal semiconductor device electrical connections. Four classifications of wire are distinguished, (1) copper-modified wire, (2) beryllium-modified wire, ( 3) high-strength wire, and (4) special purpose wire.
Note 1--Trace metallic elements have a significant effect upon the mechanical properties and thermal stability of high-purity gold wire. It is customary in manufacturing to add controlled amounts of selected impurities to gold to modify or stabilize bonding wire properties or both. This practice is known variously as "modifying,"" stabilizing," or "doping." The first two wire classifications denoted in this specification refer to wire made with either of two particular modifiers, copper or beryllium, in general use. In the third and fourth wire classifications, "high-strength" and "special purpose" wire, the identity of modifying additives is not restricted.
1.2 The values stated in SI units shall be regarded as the standard.
1.2.1 A mixed system of metric and inch-pound units is in widespread use for specifying semiconductor lead-bonding wire. SI-equivalent values of other commonly used units are denoted by parentheses in text and tables.
1.3 The following hazard caveat pertains only to the test method portion, Section 9, of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• Technical Committee: F01 - Electronics

Relations

• Replaced By: ASTM F72-95(2001) - Standard Specification for Gold Wire for Semiconductor Lead Bonding
• Effective Date: 01-Jan-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 72 – 95
Standard Specification for
Gold Wire for Semiconductor Lead Bonding
This standard is issued under the fixed designation F 72; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Ordering Information
1.1 This specification covers round drawn/extruded gold 3.1 Orders for material under this specification shall include
wire for internal semiconductor device electrical connections. the following information:
Four classifications of wire are distinguished, (1) copper- 3.1.1 Classification: copper-modified, beryllium-modified,
modified wire, (2) beryllium-modified wire, ( 3) high-strength high strength, or special purpose,
wire, and (4) special purpose wire. 3.1.2 Quantity,
3.1.3 Purity (Section 4),
NOTE 1—Trace metallic elements have a significant effect upon the
3.1.4 Type, hard, stress relieved, or annealed (Section 5),
mechanical properties and thermal stability of high-purity gold wire. It is
3.1.5 Breaking load and percentage elongation range (Sec-
customary in manufacturing to add controlled amounts of selected
tion 5),
impurities to gold to modify or stabilize bonding wire properties or both.
This practice is known variously as “modifying,”“ stabilizing,” or
3.1.6 Wire diameter (Section 6),
“doping.” The first two wire classifications denoted in this specification
3.1.7 Spool type, length of wire per spool, and type of wind
refer to wire made with either of two particular modifiers, copper or
(Section 11),
beryllium, in general use. In the third and fourth wire classifications,
3.1.8 Despooling, left-handed unwind or right-handed un-
“high-strength” and “special purpose” wire, the identity of modifying
wind (Section 11), and,
additives is not restricted.
3.1.9 Packaging and marking (Section 12).
1.2 The values stated in SI units shall be regarded as the
standard.
4. Chemical Composition
1.2.1 A mixed system of metric and inch-pound units is in
4.1 Copper-modified material shall conform to the chemical
widespread use for specifying semiconductor lead-bonding
requirements specified in Table 1.
wire. SI-equivalent values of other commonly used units are
4.2 Beryllium-modified material shall conform to the
denoted by parentheses in text and tables.
chemical requirements specified in Table 2.
1.3 The following hazard caveat pertains only to the test
4.3 High-strength material shall conform to the chemical
method portion, Section 9, of this specification. This standard
requirements specified in Table 3.
does not purport to address all of the safety concerns, if any,
4.4 Special purpose material shall be in accordance with
associated with its use. It is the responsibility of the user of this
Table 4.
standard to establish appropriate safety and health practices
NOTE 2—Copper-modified wire is used on thermocompression wire
and determine the applicability of regulatory limitations prior
bonding machines. Beryllium-modified material is often preferred on
to use.
high-speed automated thermocompression or thermosonic bonding equip-
ment. High-strength wire was developed for use on some very high speed
2. Referenced Documents
automated thermosonic bonders.
2.1 ASTM Standards:
F 16 Test Methods for Measuring Diameter or Thickness of 5. Mechanical Properties
Wire and Ribbon for Electronic Devices and Lamps
5.1 Material specified by this standard may be either of two
F 205 Test Method for Measuring Diameter of Fine Wire
types:
by Weighing
5.1.1 Hard—Wire, as drawn/as extruded.
F 219 Test Methods of Testing Fine Round and Flat Wire
5.1.2 Annealed—Wire, annealed after drawing/extruding.
for Electron Devices and Lamps
5.2 Breaking Load and Elongation—The tension test shall
F 584 Practice for Visual Inspection of Semiconductor
be the standard test for determining the mechanical properties,
Lead-Bonding Wire
and acceptance or rejection shall depend on the breaking load
and percent elongation at failure of a 254-mm (10.0-in.) length
This specification is under the jurisdiction of ASTM Committee F-1 on of wire.
Electronics and is the direct responsibility of Subcommittee F01.07 on Wire
5.2.1 Hard wire shall conform to the requirements of Table
Bonding.
5 for copper-modified gold wire and to the requirements of
Current edition approved April 15, 1995. Published June 1995. Originally
published as F 72 – 66 T. Last previous edition F 72 – 94. Table 6 for beryllium-modified gold wire.
Annual Book of ASTM Standards, Vol 10.04.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
F72
TABLE 1 Chemical Requirements, Copper-Modified Gold TABLE 6 Breaking Load and Elongation of Hard Wire—
Bonding Wire Beryllium-Modified Gold and High-Strength Gold
Element Composition, Weight, % Nominal Diameter, Breaking Load, min, N Elongation in 254 mm
μm (in.) (gf) 10.0 in.), %
Gold, min 99.99
Beryllium, max 0.0001 13 (0.00050) 0.039 (4.0) 0.5 to 2.0, incl
Copper 0.003–0.006 18 (0.00070) 0.069 (7.0) 0.5 to 2.0, incl
Silver, max 0.006 20 (0.00080) 0.088 (9.0) 0.5 to 2.0, incl
Other impurities, max each 0.003 23 (0.00090) 0.147 (15.0) 1.0 to 2.5, incl
Total of all detectable elements, max 0.01 25 (0.0010) 0.177 (18.0) 1.0 to 2.5, incl
28 (0.0011) 0.216 (22.0) 1.0 to 2.5, incl
30 (0.0012) 0.265 (27.0) 1.0 to 2.5, incl
31.8 (0.00125) 0.284 (29.0) 1.0 to 2.5, incl
TABLE 2 Chemical Requirements, Beryllium-Modified Gold
33 (0.0013) 0.314 (32.0) 1.0 to 2.5, incl
Bonding Wire
38 (0.0015) 0.392 (40.0) 1.0 to 2.5, incl
51 (0.0020) 0.736 (75.0) 1.0 to 3.0, incl
Element Composition, Weight, %
Gold, min 99.99
Beryllium 0.0003–0.0010
TABLE 7 Breaking Load and Elongation of Stress Relieved/
Other impurities, max each 0.003
Total of all detectable impurities, max 0.01 Annealed Wire—Copper-Modified Gold
Nominal Breaking Load, Elongation in 254 mm
Diameter, min, (10.0 in.), %
μm (in.) N (gf)
TABLE 3 Chemical Requirements, High-Strength Gold Bonding A
Min Max Range
Wire
13 (0.00050) 0.0098 (1.0) 0.5 3.0 2
Element Composition, Weight, %
18 (0.00070) 0.020 (2.0) 0.5 7.0 3
20 (0.00080) 0.029 (3.0) 0.5 8.0 3
Gold, min 99.99
23 (0.00090) 0.049 (5.0) 0.5 8.0 3
Total of all detectable impurities, max 0.01
25 (0.0010) 0.059 (6.0) 0.5 10.0 3
28 (0.0011) 0.069 (7.0) 0.5 10.0 3
30 (0.0012) 0.078 (8.0) 0.5 10.0 3
31.8 (0.00125) 0.088 (9.0) 0.5 10.0 3
TABLE 4 Chemical Requirements, Special Purpose Gold
33 (0.0013) 0.0981 (10.0) 0.5 10.0 3
Bonding Wire
38 (0.0015) 0.118 (12.0) 0.5 12.0 4
Element Composition, Weight, %
51 (0.0020) 0.196 (20.0) 0.5 15.0 4
A
Gold Not restricted
A range of permissible elongation of at least the number of percentage points
Other principal elements Not restricted
shown shall be selected from within the overall range designated by the minimum
Total of all detectable elements Not restricted
and maximum values for the given diameter. For example, for wire of 25-μm
(0.0010-in.) diameter, copper-modified gold wire, permissible elongation of 4.0 to
7.0, 6.0 to 9.0, 7.0 to 10.0 %, etc., may be selected.
TABLE 5 Breaking Load and Elongation of Hard Wire—Copper-
Modified Gold
TABLE 8 Breaking Load and Elongation of Stress Relieved/
Annealed Wire—Beryllium-Modified Gold
Nominal Diameter, Breaking Load, min, N Elongation in 254 mm
μm (in.) (gf) (10.0 in.), %
Nominal Breaking Load, Elongation in 254 mm
Diameter, min, (10.0 in.), %
13 (0.00050) 0.029 (3.0) 0.5 to 2.0, incl
μm (in.) N (gf)
A
18 (0.00070) 0.059 (6.0) 0.5 to 2.0, incl
Min Max Range
20 (0.00080) 0.078 (8.0) 0.5 to 2.0, incl
13 (0.00050) 0.020 (2.0) 0.5 3.0 2
23 (0.00090) 0.127 (13.0) 1.0 to 2.5, incl
18 (0.00070) 0.029 (3.0) 0.5 7.0 3
25 (0.0010) 0.157 (16.0) 1.0 to 2.5, incl
20 (0.00080) 0.039 (4.0) 0.5 8.0 3
28 (0.0011) 0.196 (20.0) 1.0 to 2.5, incl
23 (0.00090) 0.059 (6.0) 0.5 8.0 3
30 (0.0012) 0.235 (24.0) 1.0 to 2.5, incl
25 (0.0010) 0.069 (7.0) 0.5 10.0 3
31.8 (0.00125) 0.255 (26.0) 1.0 to 2.5, incl
28 (0.0011) 0.078 (8.0) 0.5 10.0 3
33 (0.0013) 0.275 (28.0) 1.0 to 2.5, incl
30 (0.0012) 0.0981 (10.0) 0.5 10.0 3
38 (0.0015) 0.343 (35.0) 1.0 to 2.5, incl
31.8 (0.00125) 0.108 (11.0) 0.5 10.0 3
51 (0.0020) 0.686 (70.0) 1.0 to 3.0, incl
33 (0.0013) 0.118 (12.0) 0.5 10.0 3
38 (0.0015) 0.147 (15.0) 0.5 12.0 4
51 (0.0020) 0.245 (25.0) 0.5 15.0 4
A
A range of permissible elongation of at least the number of percentage points
5.2.2 Stress relieved/annealed wire shall conform to the
shown shall be selected from within the overall range designated by the minimum
and maximum values for the given diameter. For example, for wire of 25-μm
requirements of Table 7 for copper-modified gold wire, the
(0.0010-in.) diameter, permissible elongation of 4.0 to 7.0, 6.0 to 9.0, 7.0 to 10.0 %,
requirements of Table 8 for beryllium-modified gold wire, to
etc., may be selected.
the requirements of Table 9 for high-strength wire, and to the
requirements of Table 10 for special purpose wire. 7. Workmanship, Finish, and Appearance
7.1 The wire surface shall be clean and free of finger oils
NOTE 3—Hard wire is generally used for ultrasonic wire bonding.
Annealed wire is used for thermocompression and thermosonic bonding. and stains.
7.2 The wire surface shall be free of drawing/extrusion
6. Dimensions and Permissible Variations
lubricant residues, particulate matter and other contaminants
6.1 Wire diameters shall be expressed in μm (or equivalent that would interfere with functional performance of the wire.
decimal fractions of an inch). Tolerances for the various size The seller and the purchaser must agree upon acceptable
ranges are specified in Table 11. standard of surface cleanliness.
F72
TABLE 9 Breaking Load and Elongation of Stress Relieved/
purchaser must agree upon acceptable amount of curl. Curl is
Annealed Wire—High-Strength Gold
measured by the springback test (9.5).
Elongation in 254 mm
7.6 The wire must be free of twist about the wire axis.
A
Nominal Diameter, Breaking Load, min,
(10.0 in.), %
Referring to wire twist test procedure (9.6), wire entwining
μm (in.) N (gf)
Min Max
upon itself one or more complete turns (9.6.5.4) is rejectable by
13 (0.00050) 0.020 (2.0) 0.5 3.0
the purchaser. Lesser degrees of twist may be acceptable, as
18 (0.00070) 0.039 (4.0) 0.5 5.0
agreed upon between seller and purchaser.
20 (0.00080) 0.040 (5.0) 0.5 6.0
7.7 The wire cross section must not be out-of-round to such
23 (0.00090) 0.064 (6.5) 0.5 6.0
25 (0.0010) 0.078 (8.0) 0.5 6.0
an extent that functional performance is impaired. The seller
28 (0.0011) 0.093 (9.5) 0.5 6.0
and the purchaser must agree upon acceptable amount of
30 (0.0012) 0.113 (11.5) 0.5 6.0
out-of-roundness.
31.8 (0.00125) 0.123 (12.5) 0.5 6.0
33 (0.0013) 0.132 (13.5) 0.5 6.0
NOTE 4—It is the intention of the directly responsible Subcommittee,
38 (0.0015) 0.176 (18.0) 0.5 7.0
51 (0.0020) 0.314 (32.0) 0.5 7.0 F01.07, that the term “functional performance” be narrowly construed as
A follows: wire imperfections denoted in 7.2, 7.5, and 7.7 must not be of
Except for 13 μm, 38 μm, and 51 μm, the minimum-maximum range is usually
sufficient severity to excessively impair the operation of an otherwise
3 percentage points, for example, 2 to 5, 3 to 6, and 4 to 7 %. For 13 μm it is
usually 1.5 percentages points, for example, 0.5 to 2, 1 to 2.5, and 1.5 to 3 %. For
normally functioning wire bonding machine. In practice, standards of
38 μm and 51 μm it is usually 4 percentage points, for example, 0.5 to 4.5, 1 to 5,
adequate “functional performance” vary considerably, depending upon
2to6,and3to7%.
application.
8. Sampling
TABLE 10 Breaking Load and Elongation of Stress Relieved/
Annealed Wire-Special Purpose 8.1 Unless otherwise agreed, conformance with Section 5
shall be determined by samples from each lot of wire.
Nominal Breaking Load, Elongation in 254 mm
Diameter, min, (10.0 in.), %
8.2 Lot Sampling— A lot shall consist of all material from
μm (in.) N (gf)
A
Min Max Range
one melt or bar in a shipment against one order description.
8.3 Sampling Plan:
13 (0.00050) To be determined 0.5 3.0 1.5
18 (0.00070) between wire user 0.5 7.0 2.0
8.3.1 A spool of wire used for testing may not be useful for
and wire
20 (0.00080) 0.5 8.0 2.0
production. Choose a sampling plan that will permit scrapping
23 (0.00090) manufacturer 0.5 8.0 2.0
of test spools as gold wire, particularly of small diameter, is
25 (0.0010) 0.5 10.0 2.0
28 (0.0011) 0.5 10.0 2.0
easily damaged.
30 (0.0012) 0.5 10.0 2.0
8.3.2 Select the number of spools that will give a represen-
31.8 (0.00125) 0.5 10.0 2.0
tative sampling, as agreed upon between the purchaser and the
33 (0.0013) 0.5 10.0 2.0
38 (0.0015) 0.5 12.0 2.0
seller.
51 (0.0020) 0.5 15.0 2.0
8.4 Number of Samples:
A
A range of permissible elongation of at least the number of percentage points
8.4.1 Take samples from not less than 1 % of the spools
shown shall be selected from within the overall range designated by the minimum
from each lot.
and maximum values for the given diameter. For example, for wire of 25-μm
(0.0010-in.) diameter, a permissible elongation of 4.0 to 6.0, 6.0 to 8.0, 7.0 to
8.4.2 Take not less than three samples from each spool.
9.0 %, etc., may be selected.
9. Test Methods
9.1 Chemical Requirements—Perform chemical analysis
TABLE 11 Dimensional Tolerances
using an emission spectrograph or other method having equiva-
Standard Tolerance Special Purpose Tolerance
Nominal
%of %of
lent sensitivity. Cross-check individual constituents (for ex-
Diameter, %of %of
Nominal Nominal
μm (in.) Nominal Weight Nominal Weight ample, copper or beryllium) by using atomic absorption
Diameter Diameter
spectrometric or other appropriate quantitative analytical
13 (0.00050) 66 615 + 6/−2 + 1/−10
Over 13 to 25 63 610 + 6/−2 + 1/−6
method. The seller and the purchaser must agree upon analyti-
(over 0.0005 to
cal techniques to be employed.
0.0010), incl
9.2 Breaking Load and Elongation—Apply the tension test
Over 25 to 51 63 66 + 3/−0.5 + 1/−4
(over 0.0010 to
in accordance with Test Methods F 219.
0.0020)
9.3 Wire Diameter— Measure the wire diameter by one of
the following methods:
9.3.1 Measure the diameter directly with apparatus and
7.3 The surface shall be free of surface contamination that procedure in accordance with Test Methods F 16. Because
would degrade service life of the device to which it is attached.
annealed gold wire is very soft, exercise caution when using
The seller and the purchaser must agree upon acceptable the direct-measurement method to prevent deformation of the
standard of surface cleanliness.
wire.
7.4 The wire surface shall be free of nicks, dents, scratches, 9.3.2 M
...