Vacuum reacting force welding method and device thereof

A vacuum reacting force welding method, comprising the following steps: a chip being die-bonded onto a substrate by means of a solder to form a semi-finished product (16); the semi-finished product being placed within a vacuum eutectic cavity (6) of a vacuum eutectic stove; vacuum-pumping the vacuum eutectic cavity; preheating the vacuum eutectic cavity to slowly increase the temperature; heating the vacuum eutectic cavity quickly to melt the solder; applying an acting force to the vacuum eutectic cavity to raise the vacuum eutectic cavity acceleratedly after lowering same; performing forced refrigeration to the exterior of the vacuum eutectic cavity, while introducing a protective gas to the interior thereof; releasing the vacuum state of the vacuum eutectic cavity after the solder is solidified. Also disclosed is a welding device using the vacuum reacting force welding method. The welding method and device can apply, under the precondition of avoiding damage to the chip, a reacting force with acceleration to the chip, effectively lowering the voidage of the welding spot.