Ball mounting device and ball mounting method

Abstract

The purpose of this invention is to provide a ball mounting device that allows a wafer to be in close contact with an adsorption stage via a thin sheet without causing damage to the wafer, and that can also mount conductive balls on extremely thin wafers that are prone to warping. The ball mounting device 1 includes a flux printing device 20 for printing flux F onto the wafer 10, a ball feeding device 30 for feeding conductive balls 3 onto the wafer 10, and a clamping unit 40 for clamping the wafer transport workpiece W. The clamping unit 40 includes an adsorption stage 41 that vacuum-adsorbs the wafer 10 via a thin sheet 9, a clamping ring 43 that clamps a transport ring 8 in the thickness direction, and an annular clamping stage 44, a drive mechanism that applies a tensile force to the thin sheet 9 by moving the transport ring 8 relative to the height of the wafer 10, and a control mechanism for controlling the tensile force.

Claims

1. A ball-carrying device, characterized in that it comprises: a clamping unit for clamping a wafer transport workpiece, the wafer transport workpiece comprising a stretchable sheet and a wafer disposed radially inside a transport ring on which the sheet is stretched, and temporarily attached to the sheet; a flux printing device for printing flux onto the wafer; a ball-feeding device for feeding conductive balls onto the wafer printed with the flux; and a clamping unit transfer mechanism for transferring the clamping unit to the flux printing device or the ball-feeding device; and the clamping unit comprising: an adsorption stage for vacuum adsorbing the wafer via the sheet; a clamping ring and an annular clamping stage for clamping the transport ring in the thickness direction; a drive mechanism for moving the transport ring relative to the height position of the wafer to apply a tensile force to the sheet; and a control mechanism for controlling the tensile force. A wafer pressing member that presses the outer periphery of the wafer against the adsorption stage to correct the warping of the wafer; and a wafer pressing member lifting actuator that moves the wafer pressing member up and down toward the wafer; and the wafer pressing member lifting actuator has a ball screw mechanism and is configured to control the retraction speed of the wafer pressing member.

2. The ball-mounting device as claimed in claim 1, wherein the control mechanism comprises: a linear encoder that detects the distance the conveying ring or the adsorption stage moves from the reference position, using the height position of the wafer when the adsorption stage vacuum adsorbs it as a reference position.

3. The ball mounting device of claim 1, wherein the drive mechanism is a ball screw mechanism comprising a ball screw shaft, a ball screw nut and a servo motor, and the control mechanism is configured to control the tensile force applied to the sheet by controlling the rotational torque of the servo motor.

4. The ball-mounting device of claim 1, wherein the clamping unit has a lifting pin for supporting the wafer in the wafer transport workpiece, or a lifting pin for supporting the transport ring; the lifting pin protrudes in the direction of suspending and supporting the wafer transport workpiece from the adsorption stage when the wafer transport workpiece is fed to the clamping unit or unloaded from the clamping unit.

5. The ball-mounting device of claim 1, wherein the adsorption stage has a vacuum suction port; the vacuum suction port is switchable to perform vacuum suction when adsorbing the wafer transport workpiece and to spray air onto the wafer transport workpiece when releasing the adsorption between the wafer transport workpiece and the adsorption stage.

6. A ball mounting method, characterized in that it mounts conductive balls on a wafer of a wafer transport workpiece, the wafer transport workpiece comprising the wafer disposed radially inside a transport ring having a stretchable sheet stretched on it and temporarily attached to the sheet, and comprising: a step of transporting the wafer transport workpiece to a clamping unit; a step of vacuum adsorbing the wafer transport workpiece onto an adsorption stage; a clamping step in which the transport ring is clamped by a clamping ring and a clamping stage, and the sheet is subjected to a tensile force to clamp the wafer transport workpiece; and a flux printing step in which the clamping unit is transferred to a flux printing apparatus to print flux onto the wafer. The ball feeding process involves transferring the clamping unit from the flux printing device to the ball feeding device to feed conductive balls onto the wafer; and transferring the clamping unit from the ball feeding device to the conveying start position to unload the wafer conveying workpiece from the clamping unit; the clamping process is achieved by controlling the tensile force applied to the wafer by controlling the relative movement of the height position of the conveying ring and the wafer through a control mechanism; the outer periphery of the wafer is pressed against the adsorption stage by a wafer pressing member to correct the warpage of the wafer; and the retraction speed of the wafer pressing member can be controlled by a ball screw mechanism.

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