Single-step die bonding is a complete single-cycle process that picks up a single die from the wafer, transfers it precisely, and fixes it onto the target substrate or lead frame. Its core purpose is to achieve high-precision alignment and firm attachment between the die and the bonding pad. For key non-standard parts in this process such as suction nozzles, dispensing tips, and ejector needles, Hansheng Automation provides single-piece or small-batch precision machining based on customer drawings.
I. Station Calibration and Pre-Preparation
(1) Wafer stage positioning
The wafer stage moves the wafer to be processed to the pick-up station. The industrial vision system captures features such as dicing streets and edge alignment marks, adjusts the X/Y position of the stage, and aligns the pick-up center of the target die directly under the suction nozzle, with positioning repeatability controlled within ±0.01mm.
(2) Substrate station adjustment (additional for adhesive dispensing die bonding)
The conveying mechanism moves the target substrate or lead frame to the bonding station. The vision system captures the substrate pads and lead positioning marks, and adjusts the substrate position to the placement reference position. For adhesive dispensing die bonding, the dispensing head moves simultaneously above the pad and dispenses a fixed amount of solder paste or conductive adhesive, with dispensing accuracy controlled within ±0.02mm.
II. Nozzle Pre-Treatment and Die Pick-Up
(1) Nozzle condition detection
The system automatically checks nozzle vacuum level to ensure vacuum pressure remains stable between -65kPa and -85kPa. Compressed air is also used to blow the nozzle tip to remove residual solder paste, die debris, or contamination.
(2) Die adsorption and lifting
The nozzle moves downward along the Z-axis at 6–9mm/s, contacts the target die surface, and maintains a dwell time of 150–250ms, using vacuum adsorption to firmly hold the die.
The nozzle lifts along the Z-axis to a safe height of 1–2.5mm to avoid scratching adjacent wafers or stage structures.
III. Die Transfer and Alignment
(1) Multi-axis coordinated movement
The bonding head carrying the nozzle moves along the X/Y axes to above the substrate bonding station. The vision system captures real-time position deviation between the die edge and the substrate pad, and the servo system adjusts the X/Y/Z axes and rotation angle of the bonding head to align the die leads with the substrate pads, with alignment accuracy controlled within ±0.005mm.
(2) Process adaptation
For eutectic die bonding, the heating unit activates at this stage to preheat the substrate or die to the temperature range required for eutectic soldering (150℃–300℃, depending on solder type). Operators should avoid the high-temperature area to prevent burns.
IV. Die Placement and Fixing
(1) Placement and dwell
The nozzle moves downward along the Z-axis at 3–7mm/s, placing the die smoothly onto the solder paste, adhesive film, or eutectic solder on the substrate pad, ensuring full contact between the die and the pad with no gap.
Downward nozzle pressure is maintained for 100–300ms, sustaining ambient temperature until the die is initially fixed, the adhesive film is cured, or the solder is preliminarily fused.
V. Nozzle Release and Process Reset
(1) Nozzle release and cleaning
The nozzle vacuum system is turned off, and compressed air at 0.1–0.2MPa is introduced to blow the nozzle tip, ensuring the die fully releases from the nozzle with no residual adhesion.
(2) Reset and standby
The nozzle lifts along the Z-axis to a safe standby height and returns to the initial standby position, waiting for the next cycle trigger signal.
