Case Study: Gold Wire Ball Bonding Against Reflow

by | Oct 1, 2019 | 0 comments

Multiple Reflows at Various Gold Thicknesses

Experimented by: Sneha Kaul and Christina Lum

Objective

To determine if multiple rounds of reflow detrimentally affect the surface condition of the gold plating at any thickness, using gold wire bonding as the test.

Introduction

Boards pertaining to a particular customer design (see Figure 1) were collected in array form and selected based on their respective plating thickness. For this test, boards with approximately 1 µin, 2 µin, 3 µin, and 5 µin of gold were evaluated via wire bond testing after each round of three reflows without flux. In order to achieve these various gold thicknesses, such as 1 µin or 5 µin of gold, the plating time for the respective sample array had to be adjusted accordingly.

XRF ENEPIG Readings

For 1 µin For 2 µin For 3 µin For 5 µin
1.1 µin Au

10.8 µin Pd

171.9 µin Ni

1.8 µin Au

6.2 µin Pd

140.0 µin Ni

3.0 µin Au

11.3 µin Pd

220.9 µin Ni

5.8 µin Au

6.6 µin Pd

203.2 µin Ni

1.2 µin Au

10.4 µin Pd

163.4 µin Ni

1.9 µin Au

10.2 µin Pd

170.5 µin Ni

2.7 µin Au

10.7 µin Pd

197.9 µin Ni

4.4 µin Au

11.2 µin Pd

209.6 µin Ni

 

 

Reflow Control Parameters

Chamber Temperature (ºC) Chamber Temperature (ºC)
1T 120 6T 240
1B 120 6B 240
2T 150 7T 258
2B 150 7B 258
3T 185 8T 265
3B 185 8B 265
4T 210 9T 220
4B 210 9B 220
5T 230 10T 200
5B 230 10B 200

Before reflow, two boards (labeled as Board 1 and Board 2) from each array with either of the three thicknesses were wire bond tested to attain control values. Once the array underwent a round of reflow, the following two boards in the array were tested. For the three reflows, twenty-four boards (eight boards for each of the three thicknesses) were evaluated.

Gold wire bonding Bottom wire bond pads

Gold Wire Bonding Six Central Pads

Figure 1: Design of #126756 (top), #131721 (top), and #130348 (bottom)

For every new board, the top and bottom wire bond pads were tested; first as a control on the first two boards and then on every board following one round of reflow. After every reflow, six central pads from the previously tested boards were evaluated as well in order to observe any new changes on the same board.

Gold wire bonding pull strength

Per IPC-TM-650-2.4.42.3, gold wire bonding requires a minimum of 3.0 gram-force (gf) for the pull strength (resistance of the wire to withstand breakage). At the request of a customer, the break mode for this particular customer design is also evaluated for no wire breaks at points A or E (see figure to the right). Therefore for this test, any pull strength below 3.0 gf or breaks at any of the 5 points (A through E) were considered as fails.

Experimental Results

A. 1 µin of Gold

Before Reflow

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.6 B Pass 6.6 C Pass
8.1 B Pass 8.0 B Pass
6.0 B Pass 7.3 B Pass
8.6 B Pass 7.2 B Pass
7.3 B Pass 9.0 B Pass
7.3 B Pass 7.9 B Pass
6.8 B Pass 8.9 B Pass
9.2 B Pass 9.6 B Pass
8.6 B Pass 9.0 B Pass
7.6 B Pass 9.1 B Pass
8.9 B Pass 9.2 B Pass
8.8 B Pass 8.8 B Pass
9.9 C Pass 9.3 B Pass
8.3 C Pass 10.5 B Pass

1st Round of Reflow

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.7 B Pass 5.8 B Pass
8.5 B Pass 8.7 B Pass
8.1 B Pass 8.4 B Pass
7.7 B Pass 7.7 B Pass
7.4 B Pass 5.6 B Pass
7.3 B Pass 8.0 B Pass
9.7 B Pass 9.8 B Pass
10.2 B Pass 8.6 B Pass
8.9 B Pass 11.4 B Pass
8.0 B Pass 8.2 B Pass
7.6 B Pass 7.7 B Pass
8.2 B Pass 7.6 B Pass
7.9 B Pass 8.6 B Pass
Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.9 B Pass 8.4 B Pass
8.7 B Pass 7.5 B Pass
8.2 B Pass 7.3 B Pass
6.9 B Pass 8.9 B Pass
8.3 B Pass 6.4 B Pass
8.7 B Pass 6.5 B Pass

2nd Round of Reflow

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.8 B Pass 8.7 B Pass
7.0 B Pass 7.5 B Pass
7.0 B Pass 7.6 B Pass
7.4 B Pass 8.8 B Pass
6.3 B Pass 6.9 B Pass
8.1 B Pass 7.0 B Pass
9.1 B Pass 9.3 B Pass
9.3 B Pass 9.2 B Pass
5.9 E Pass 9.4 B Pass
9.1 B Pass 9.7 B Pass
9.8 B Pass 9.7 C Pass
8.6 B Pass 8.1 B Pass
10.9 B Pass 9.9 B Pass
9.3 B Pass 10.2 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.1 B Pass 7.9 B Pass
7.1 B Pass 7.1 B Pass
8.3 B Pass 6.8 B Pass
8.3 B Pass 7.8 B Pass
8.7 B Pass 7.4 B Pass
7.0 B Pass 8.4 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
10.6 B Pass 10.0 B Pass
10.6 B Pass 10.2 B Pass
10.2 B Pass 9.9 C Pass
7.0 B Pass 8.1 B Pass
8.3 B Pass 7.9 B Pass
6.1 B Pass 7.4 B Pass

 

 3rd Round of Reflow

Board 7 Board 8
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.0 B Pass 8.6 B Pass
6.2 B Pass 8.7 B Pass
6.2 B Pass 9.0 B Pass
8.2 B Pass 8.6 B Pass
8.1 B Pass 7.1 B Pass
9.3 B Pass 7.9 B Pass
9.4 B Pass 9.6 B Pass
9.5 B Pass 9.6 B Pass
9.2 B Pass 9.4 B Pass
10.0 C Pass 9.0 B Pass
10.3 B Pass 10.2 B Pass
10.0 B Pass 10.1 B Pass
9.5 B Pass 10.8 B Pass
10.2 B Pass 11.0 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.4 B Pass 5.8 B Pass
8.6 B Pass 8.2 B Pass
7.0 B Pass 8.5 B Pass
7.5 B Pass 8.2 B Pass
7.4 B Pass 7.4 B Pass
7.4 B Pass 8.9 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
10.7 C Pass 11.4 B Pass
9.7 B Pass 9.1 B Pass
10.3 B Pass 10.8 B Pass
6.4 B Pass 6.8 B Pass
7.5 B Pass 8.6 B Pass
8.6 B Pass 7.1 B Pass

 

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.6 B Pass 7.9 B Pass
7.7 B Pass 7.9 B Pass
6.9 B Pass 4.3 B Pass
6.8 B Pass 8.0 B Pass
5.9 B Pass 6.7 B Pass
7.4 B Pass 7.8 B Pass

 

B. 2 µin of Gold

Before Reflow

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.3 B Pass 7.6 B Pass
6.5 B Pass 7.2 B Pass
7.3 B Pass 7.1 B Pass
7.1 B Pass 8.7 B Pass
6.7 B Pass 7.8 B Pass
7.2 B Pass 7.8 B Pass
7.1 B Pass 8.7 C Pass
7.9 B Pass 8.8 B Pass
8.4 C Pass 7.9 B Pass
9.3 B Pass 8.9 C Pass
8.7 B Pass 9.0 B Pass
9.5 B Pass 8.2 B Pass
9.6 C Pass 9.7 B Pass
10.3 C Pass 9.1 B Pass

1st Round of Reflow

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.1 B Pass 8.1 B Pass
7.4 B Pass 8.2 B Pass
6.8 B Pass 7.1 B Pass
7.3 B Pass 7.3 B Pass
6.9 B Pass 6.9 B Pass
8.8 B Pass 7.1 B Pass
9.3 B Pass 10.7 C Pass
8.7 B Pass 9.6 B Pass
8.8 B Pass 9.4 B Pass
9.4 B Pass 9.2 B Pass
9.1 B Pass 8.7 B Pass
7.8 B Pass 9.2 C Pass
9.5 B Pass 10.3 B Pass
10.3 B Pass 8.4 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.9 B Pass 7.8 B Pass
7.2 B Pass 6.7 B Pass
8.9 B Pass 5.8 B Pass
8.3 B Pass 8.3 B Pass
5.7 B Pass 8.7 B Pass
8.1 B Pass 6.6 B Pass

2nd Round of Reflow

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.9 B Pass 7.9 B Pass
7.7 B Pass 8.3 B Pass
8.0 B Pass 7.4 B Pass
8.2 B Pass 5.6 E Pass
8.5 B Pass 7.4 B Pass
7.5 B Pass 6.2 E Pass
8.9 B Pass 9.4 B Pass
9.1 B Pass 9.7 C Pass
9.4 B Pass 9.6 B Pass
8.0 B Pass 9.6 B Pass
8.4 B Pass 9.5 B Pass
9.6 B Pass 8.6 B Pass
7.8 B Pass 10.4 B Pass
10.2 B Pass 9.2 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
9.7 B Pass 9.5 B Pass
7.5 B Pass 7.4 B Pass
9.5 B Pass 10.0 B Pass
6.7 B Pass 7.3 B Pass
8.1 B Pass 9.0 E Pass
6.3 B Pass 7.0 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.0 B Pass 8.0 B Pass
9.4 B Pass 3.1 A Pass
8.3 B Pass 8.3 B Pass
8.8 B Pass 8.9 B Pass
8.7 B Pass 6.9 E Pass
7.4 B Pass 8.1 B Pass

 

3rd Round of Reflow

Board 7 Board 8
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.4 B Pass 7.6 B Pass
6.8 B Pass 7.5 B Pass
7.4 B Pass 7.6 B Pass
7.8 B Pass 6.3 B Pass
7.8 B Pass 8.2 B Pass
9.0 B Pass 5.8 B Pass
7.9 B Pass 10.0 B Pass
9.3 B Pass 8.4 B Pass
9.4 B Pass 7.6 B Pass
8.0 B Pass 8.1 E Pass
8.6 B Pass 8.3 B Pass
7.1 B Pass 9.5 B Pass
9.6 B Pass 10.4 B Pass
8.3 C Pass 1.5 A Fail*

*Possible anomaly due to poor wire placement.

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.7 B Pass 8.1 B Pass
7.1 B Pass 7.0 B Pass
6.8 E Pass 7.6 B Pass
7.4 B Pass 5.9 B Pass
8.2 B Pass 7.4 B Pass
6.6 E Pass 7.5 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
9.2 B Pass 9.3 B Pass
9.2 B Pass 9.6 B Pass
9.0 C Pass 7.0 E Pass
6.7 B Pass 8.1 B Pass
5.7 B Pass 8.1 B Pass
8.1 B Pass 7.5 B Pass
Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
9.5 B Pass 9.4 B Pass
9.2 B Pass 9.8 B Pass
9.6 B Pass 9.7 B Pass
8.0 B Pass 7.9 B Pass
7.8 B Pass 8.5 B Pass
6.9 B Pass 8.7 B Pass

C. 3 µin of Gold

Before Reflow

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.1 B Pass 7.2 B Pass
5.9 B Pass 5.3 B Pass
6.3 E Pass 7.8 B Pass
7.0 B Pass 6.5 B Pass
7.1 B Pass 6.5 B Pass
6.7 B Pass 7.4 B Pass
7.6 B Pass 7.8 B Pass
8.3 E Pass 8.8 B Pass
8.0 B Pass 8.5 C Pass
8.5 B Pass 7.8 B Pass
8.0 B Pass 7.5 B Pass
8.2 E Pass 9.0 B Pass
9.5 C Pass 9.4 C Pass

1st Round of Reflow

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.5 B Pass 8.1 B Pass
7.1 B Pass 7.4 B Pass
8.0 B Pass 5.3 B Pass
7.2 B Pass 7.3 B Pass
6.6 B Pass 6.7 B Pass
7.4 B Pass 5.7 B Pass
9.4 B Pass 8.2 B Pass
9.0 B Pass 9.1 B Pass
6.7 C Pass 8.6 B Pass
7.9 B Pass 8.4 B Pass
7.5 C Pass 8.5 B Pass
8.6 B Pass 8.5 B Pass
9.1 B Pass 9.6 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.7 B Pass 7.8 B Pass
7.2 B Pass 8.2 B Pass
6.6 B Pass 8.9 B Pass
7.5 B Pass 7.9 B Pass
7.7 B Pass 7.8 B Pass
7.6 B Pass 8.7 B Pass

2nd Round of Reflow

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.3 B Pass 7.1 B Pass
6.7 B Pass 6.6 B Pass
7.8 B Pass 7.3 B Pass
7.2 B Pass 7.2 B Pass
6.4 B Pass 8.3 B Pass
5.0 E Pass 6.5 B Pass
9.1 B Pass 8.6 E Pass
8.1 C Pass 0.4 E Fail*
4.5 E Pass 9.6 B Pass
8.5 B Pass 9.2 E Pass
8.8 B Pass 9.1 E Pass
8.6 B Pass 3.1 E Pass
9.4 B Pass 7.9 B Pass

*Possible anomaly due to poor wire placement.

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
4.2 E Pass 9.4 B Pass
8.9 B Pass 9.7 B Pass
9.3 B Pass 8.1 B Pass
8.1 B Pass 7.3 B Pass
6.3 B Pass 8.1 B Pass
7.1 E Pass 6.9 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.3 B Pass 6.7 B Pass
7.4 B Pass 8.3 B Pass
6.8 B Pass 7.2 B Pass
6.5 B Pass 8.0 B Pass
6.8 B Pass 8.0 B Pass
7.2 B Pass 8.4 B Pass

 

3rd Round of Reflow

Board 7 Board 8
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.1 B Pass 7.4 E Pass
6.2 B Pass 7.6 B Pass
7.1 E Pass 8.2 B Pass
7.2 B Pass 6.9 B Pass
6.6 B Pass 6.9 B Pass
7.5 B Pass 6.7 E Pass
7.9 B Pass 9.2 E Pass
9.1 B Pass 8.2 B Pass
9.0 B Pass 9.1 B Pass
9.0 B Pass 8.1 B Pass
8.7 B Pass 9.4 B Pass
9.0 B Pass 9.8 B Pass
9.6 B Pass 9.5 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.8 B Pass 9.1 B Pass
8.5 B Pass 8.1 B Pass
7.2 B Pass 6.7 B Pass
7.6 B Pass 7.3 B Pass
7.1 B Pass 6.8 B Pass
8.0 B Pass 7.5 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
10.1 B Pass 9.3 E Pass
9.2 C Pass 8.5 B Pass
9.8 B Pass 9.9 B Pass
7.9 B Pass 7.2 B Pass
5.9 B Pass 8.5 B Pass
7.7 B Pass 8.1 B Pass

 

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.3 B Pass 8.2 B Pass
8.2 B Pass 8.5 B Pass
7.1 B Pass 7.4 B Pass
7.5 B Pass 7.9 B Pass
6.3 E Pass 7.4 B Pass
8.8 B Pass 8.6 B Pass

 

D. 5 µin of Gold

Before Reflow

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
8.0 B Pass 8.2 C Pass
8.2 B Pass 9.4 C Pass
8.5 B Pass 8.3 B Pass
8.3 B Pass 9.3 C Pass
8.7 B Pass 10.2 C Pass
8.2 B Pass 8.3 C Pass
8.6 B Pass 7.9 B Pass
9.9 B Pass 7.0 B Pass
7.7 C Pass 8.2 B Pass
8.3 B Pass 8.3 B Pass

1st Round of Reflow

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
5.7 B Pass 8.2 B Pass
6.2 B Pass 7.1 B Pass
3.8 B Pass 5.4 B Pass
7.6 B Pass 7.1 B Pass
6.7 B Pass 7.2 B Pass
6.6 B Pass 7.0 B Pass
8.9 B Pass 10.3 B Pass
9.7 B Pass 7.8 B Pass
9.2 B Pass 9.6 B Pass
8.5 B Pass 10.3 B Pass
10.0 B Pass 7.7 B Pass
8.8 B Pass 9.1 B Pass
9.2 B Pass 10.2 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.6 B Pass 6.4 B Pass
7.9 B Pass 8.0 B Pass
7.2 B Pass 8.1 B Pass
6.7 B Pass 7.0 B Pass
8.1 B Pass 6.9 B Pass
7.5 B Pass 6.5 B Pass

 

2nd Round of Reflow

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.8 B Pass 7.8 B Pass
8.2 B Pass 8.4 B Pass
7.9 B Pass 8.3 B Pass
6.7 B Pass 6.5 B Pass
6.6 B Pass 7.7 B Pass
7.6 B Pass 7.0 B Pass
8.3 C Pass 9.2 B Pass
9.2 C Pass 10.2 B Pass
9.2 B Pass 8.6 B Pass
9.0 B Pass 8.6 B Pass
9.5 B Pass 9.1 C Pass
7.7 B Pass 8.0 B Pass
11.2 B Pass 10.3 C Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
9.8 B Pass 9.1 B Pass
8.5 B Pass 8.9 B Pass
9.8 B Pass 9.2 B Pass
8.2 B Pass 7.9 B Pass
7.2 B Pass 7.3 B Pass
6.8 B Pass 7.7 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
6.9 B Pass 7.4 B Pass
9.1 B Pass 8.7 B Pass
7.0 B Pass 6.6 B Pass
6.2 B Pass 8.4 B Pass
7.3 B Pass 8.2 B Pass
8.0 B Pass 8.1 B Pass

 

3rd Round of Reflow

Board 7 Board 8
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.3 B Pass 8.0 B Pass
7.5 B Pass 8.2 B Pass
8.2 B Pass 7.0 B Pass
7.5 B Pass 7.2 B Pass
7.5 B Pass 7.7 B Pass
6.8 B Pass 7.0 B Pass
9.2 B Pass 9.0 C Pass
9.1 B Pass 8.3 C Pass
5.5 B Pass 9.5 C Pass
8.9 B Pass 8.8 B Pass
8.5 B Pass 9.1 B Pass
9.7 B Pass 6.7 C Pass
9.9 E Pass 10.2 B Pass

 

Board 1 Board 2
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
7.4 B Pass 8.4 B Pass
8.6 B Pass 7.3 B Pass
8.6 B Pass 7.3 B Pass
7.1 B Pass 8.2 B Pass
8.2 B Pass 8.2 B Pass
7.0 B Pass 6.1 B Pass

 

Board 3 Board 4
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
10.3 B Pass 10.3 B Pass
8.8 B Pass 8.9 B Pass
9.5 B Pass 8.6 B Pass
7.0 B Pass 8.0 B Pass
8.6 B Pass 8.6 B Pass
7.1 B Pass 6.4 B Pass

 

Board 5 Board 6
Pull Strength (gram-force) Break Mode Result Pull Strength (gram-force) Break Mode Result
10.3 E Pass 8.1 B Pass
9.9 B Pass 9.7 B Pass
8.6 B Pass 9.8 B Pass
7.2 B Pass 5.0 B Pass
8.9 B Pass 8.4 B Pass
8.2 B Pass 8.7 B Pass

 

Conclusion

The objective of these gold wire bonding tests was to determine if multiple rounds of reflow had detrimental effects on the surface condition of the gold plating. As reflected in the graph below, reflow had no severe impact on the gold plating as all of the wire bond values, with the exception of a few anomalies, were passing.

Most notably at lower gold thicknesses (especially 1 µin), the wire bond pull values were higher overall, even after three rounds of reflow. When the gold is thicker, oxygen will have a higher chance of penetrating the porous gold and oxidizing the nickel, especially with the accelerating force of the heat from the reflow process. As a result, the bondability and surface condition of the plating surface could be negatively affected. An example of this can be shown below in which the wire bond values at high gold thicknesses were more inconsistent after each reflow.

Effects of Reflow against Gold Thickness

As evident of these series of tests, multiple rounds of reflow do not appear to negatively impact the bondability of the gold plating. However, while the reflow process does not seem to affect the surface condition of the gold, the gold thickness should be kept to a minimum (1.2 ± 4σ µin per IPC-4556) if better bondability is desired.

In conclusion:

  • Reflow does not negatively affect gold wire bonding regardless of the gold thickness.
  • Incoming boards can safely undergo reflow at assembly up to three times without any negative results.

 

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