Precautions for LED wire bonding machine

1. Basic knowledge

(1). The length of the welding wire is ? times the wire diameter.

(2). The width of the solder joint is ? times the wire diameter.

(3). The length of the wire tail is ? times of the wire diameter.

(4). The vertical distance from the highest point of the line arc to the IC surface is?.

II.

1. Purpose

Under the simultaneous action of pressure, heat and ultrasonic energy, the gold wire is bonded between the chip electrode and the outer lead A good ohmic contact is formed between the bonding areas to complete the connection of the inner and outer leads.

2. Technical requirements

2.1 The gold wire is firmly connected to the chip electrode and lead frame bonding area

2.2 Gold wire pulling force: 25μm gold wire F minimum >5CN, average F>6CN: 32μm gold wire minimum F>8CN, average F>10CN.

2.3 Soldering point requirements

2.3.1 The first and second soldering points after gold wire bonding are shown in Figure (1) and Figure (2)

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2.3.2 Description of gold ball and wedge-shaped sizes

Golden ball diameter A: ф25um gold wire: 60-75um, which is 2.4-3.0 times of Ф;

Spherical thickness H: ф25um Gold wire: 15-20um, which is 0.6-0.8 times of Ф;

agreeable Shape length D: ф25um gold wire: 70-85um, which is 2.8-3.4 times of Ф;

2.3.3 There should be no obvious damage or thinning at the root of the gold ball, and there should be no obvious damage at the wedge-shaped part Obvious cracks

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2.4 Welding wire requirements

2.4.1 Each item The height of the gold wire bonding arch wire is appropriate, with no collapsed wire, inverted wire, or excess welding wire

2.5 Gold wire pulling force

2.5.1 The gold wire pulling force at the first soldering point is the highest with the welding wire Point test, pull upward from the highest point of the welding wire perpendicularly to the surface of the lead frame under microscope observation to test the pulling force. As shown in the figure:

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Bonding tension and breakpoint position requirements:

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3. Process conditions

Since the parameter settings of different machines are different, there is no way unified. Here I will briefly talk about the main settings:

Bonding temperature, welding time of the first and second solder points, welding pressure, welding power, arch wire height, ball burning current, tail Wire length, etc.

4. Precautions

4.1 Do not directly touch the chip and bonding area on the bracket with your hands.

4.2 Operators need to wear anti-static bracelets and anti-static overalls to avoid damage to the chip caused by static electricity.

4.3 Materials must be handled with care during transportation to avoid static electricity and collisions, and prevent wires from falling, collapsing, breaking, and adhering to debris.

4.4 When the bonding machine fails, the bonded work-in-progress should be removed from the heating plate in time to avoid the material being baked on the heating block for too long, causing cracks in the silver glue and discoloration of the bracket.

2. Bonding equipment

First, let’s go to the manual machine, which is very old

First, let’s go to the manual machine, which is very old

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ASM’s vertical machine ASM’s vertical machine

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KS machine

1488 is such an old machine, the one below is almost 20 years old< /p>

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The latest elite machine is really good, but there are some inexplicable problems occasionally, but restart It'll be fine in no time. It's probably a software problem.

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The operation of the bonding machine may be a little more complicated, and there are more parameters to be set. , the most important and difficult thing is the linear setting, which needs to be explored slowly. A good operator must understand this machine better than anyone else. Since there are many problems with parameter settings and possible occurrences, I will not list them one by one here. If you have any questions, please ask them here and we can discuss them together. I will update it as new information becomes available.