COB (CHIP ON BOARD) TECHNOLOGY: PROCESS, PROS & CONS, AND APPLICATIONS
COB (Chip on Board) is a direct semiconductor packaging technology in which bare chips (Dies) are mounted directly onto a printed circuit board (PCB) without traditional plastic or ceramic enclosures. This technology combines the two stages of “chip packaging” and “board assembly” into a single process.
What Are the Steps in the COB Process?
The standard COB manufacturing process consists of 3 main steps:
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- Die Attach / Die Bonding: Clean the bonding pads on the PCB, then use conductive adhesive (silver epoxy) or non-conductive adhesive (red glue) to securely mount the bare chip (Die) at the precise location on the circuit board.
- Wire Bonding: The core step of COB technology. Ultra-fine wires made of gold or aluminum are used to connect the chip’s bonding pads to the corresponding circuit pads on the PCB using thermo-compression or ultrasonic welding methods.
- Encapsulation / Glob-Top: Dispense a layer of epoxy resin (black or clear encapsulation) to cover the entire chip and bonding wires. This resin layer provides mechanical protection, moisture resistance, dustproofing, and anti-corrosion.
Comparison Between COB and SMT (Surface Mount Technology)
| Criteria | COB (Chip on Board) Technology | Traditional SMT Technology |
|---|---|---|
| Production Cost | Saves ~66% (only 1/3 the cost of SMT) due to omitting individual chip packaging. | Higher cost due to requiring separate component packaging. |
| Size & Weight | Ultra-thin and lightweight, optimized for miniature devices. | Occupies more space and is thicker. |
| Thermal Dissipation | Excellent heat dissipation (Chip contacts PCB copper layer directly). | Inferior heat dissipation through multiple intermediate layers. |
| Repairability | Difficult to repair (Chip cannot be replaced after encapsulation). | Components are easily replaceable and repairable if defective. |
| Manufacturing Requirements | Requires a Cleanroom environment and high-precision machinery. | Requires standard SMT production lines. |
Popular Applications of COB Technology
COB technology is widely applied in two main areas:
- RGB LEDs: COB is widely used in the production of LED modules due to its good heat dissipation and compact size.
- Medical equipment: Medical equipment (Thermometers, blood pressure monitors) requires high reliability and compact size, COB is the ideal choice.
- Traditional Devices:(Calculators, digital watches, toys (commonly seen as black resin drops known as “Glob-Top”).) COB is used in sensors and measuring devices that require high precision and durability.
- Consumer devices: Consumer electronics such as digital cameras, mobile phones(commonly seen as black resin drops known as “Glob-Top”) also use COB technology to save space and improve performance.
Manufacturing Capacity at Amtecor COB WorkshopTo satisfy the most stringent standards in microcircuit packaging and high-end electronic component manufacturing, the Amtecor COB Workshop is comprehensively invested with standardized cleanroom infrastructure and modern automated equipment lines.
1. Scale & Superior Process Technology
- Wire Bonding Equipment System: Equipped with 7 high-precision automatic wire bonders operating continuously on a closed bare-die packaging process.
- Outstanding Capacity: Total monthly production capacity reaches up to 40 million wires/bonds, ready to fulfill high-volume OEM/ODM orders with optimized delivery times.
- Standardized Production Environment:The entire chip bonding and Glob-Top encapsulation line is situated in a Cleanroom environment strictly controlled for temperature, humidity, and dust density to keep defect rates to a minimum.
2. Operational Capacity Specifications of Amtecor COB Workshop
| Criteria | Capacity Specification at Amtecor |
|---|---|
| Number of Wire Bonders | 7 fully automated machines |
| Monthly Capacity | Reaches up to 40,000,000 wires/bonds per month |
| Supported Bonding Wire Material | Aluminum Wire |
| Quality Control Process | Wire Pull Test, Microscopic Inspection, Functional Testing |
| Finishing Stage | Glob-Top Encapsulation (Moisture & vibration protection) |
COB production area image
Organizational structure of COB workshop
To receive a quote, please send technical documents to the email address tonhuynh@amtecor.com