JP2924059B2 - Semiconductor pellet mounting method and semiconductor pellet mounting apparatus - Google Patents

Abstract

PURPOSE:To obtain a good mounting state without a need for an excessive area for a scrubbing operation and even at a mounting operation on a recess- shaped part having no scrubbing area by a method wherein, when a solder is melted, a continuous pulse-shaped wind pressure is exerted on a semiconductor pellet and the pellet and the molten solder are vibrated. CONSTITUTION:At a semiconductor-pellet mounting method, a chip carrier 1 is placed on a heating stage 4; a solder 5 is placed on the chip carrier 1; a semiconductor pellet 6 is placed on the solder 5; the chip carrier 1, the solder 5 and the semiconductor pellet 6 are heated up to the melting point of the solder 5; the solder 5 is melted and, after that, cooled; the semiconductor pellet 6 is brazed onto the chip carrier 1. At the mounting method, when the solder 5 is melted, a continuous pulse-shaped wind pressure is exerted on the semiconductor pellet 6, the pellet 6 and the molten solder 5 are vibrated and the semiconductor pellet 6 is brazed onto the chip carrier 1. For example, the pressure of high-pressure nitrogen heated with a gas heating device 8 is modulated to a pulse shape by using an air-pressure adjusting device 9; the nitrogen is jetted from a jet nozzle 10.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pellet mounting method and a semiconductor pellet mounting apparatus, and more particularly to a semiconductor pellet mounting method in which a high-temperature gas is intermittently injected into a semiconductor pellet to vibrate the semiconductor pellet. The present invention relates to a non-contact mounting method of a semiconductor pellet to be mounted.

[Conventional technology]

Conventionally, this type of semiconductor pellet mounting method is to place a chip carrier on a heating table, heat to the melting point of the solder using the chip carrier, and then place the solder on the chip carrier, and when the solder is melted, tweezer the semiconductor pellet. In this case, the chip carrier and the back surface of the semiconductor pellet were soldered by scrubbing on the solder melted by being sucked or absorbed by a collet or the like, and a good mounting state was created.

[Problems to be solved by the invention]

The conventional semiconductor pellet mounting method described above requires an extra mounting area for scrubbing the semiconductor pellets, especially for scrubbing, and thus causes a problem in high integration of a hybrid integrated circuit or the like. Further, in the scrub using tweezers, mechanical contact occurs at the time of scrubbing, so that there is a possibility that the semiconductor pellet may be chipped or cracked. Also, when mounting in a recess that is deeper than the thickness of the semiconductor pellet to be mounted and is so narrow that a sufficient scrub area cannot be obtained, mounting is not possible with a collet, and scrubbing of the pellet is not sufficient even with tweezers. Alternatively, the solder may not be sufficiently conformed to the back surface of the semiconductor pellet and a satisfactory mounting state may not be obtained.

[Means for solving the problem]

A method for mounting a semiconductor pellet according to the present invention includes a heating table for heating a chip carrier, a solder and a semiconductor pellet, a nozzle for applying pressure to the semiconductor pellet by a gas flow, and a pulse gas flow for generating a continuous pulsed gas flow. The device has a device or air pressure adjusting device, and a gas flow modulated in a continuous pulse form by a pulse gas flow generating device or an air pressure adjusting device is ejected from the nozzle onto the semiconductor pellet, and the solder is melted while the semiconductor pellet is vibrated to mount the pellet. I do. Therefore, there is an advantage in that the modulated solder gas is easily absorbed into the chip carrier surface and the back surface of the semiconductor chip, because the amplitude of the modulated gas flow is linked to the melted solder.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, in which a chip carrier 1 in which a conductor layer 3 of silver palladium of about 10 μm is formed on a dielectric substrate 2 of alumina of about 0.635 mm, The chip carrier 1 is heated to about 340 ° on a heating table 4. A gold-tin alloy having a thickness of about 30 μm is placed as a solder 5 on the conductor layer 3 of the heated chip carrier 1, and a semiconductor pellet 6 is placed thereon. On the other hand, a gas heating device 8 and a pressure adjusting device 9 for adjusting the pressure in a pulsed manner as shown in FIG. 1B are connected to the high-pressure nitrogen pipe 7.
The high-pressure nitrogen heated to 0 ° C. is modulated in pressure by a pressure adjusting device 9 into a pulsed nitrogen jet, and is jetted from a jet nozzle 10 to apply a pulsed nitrogen gas stream onto the semiconductor pellet 6. The pulsed nitrogen gas flow causes the semiconductor pellet 6 to vibrate, and the vibration is transmitted to the molten solder. The conductor layer 3 and the semiconductor pellet 6 are vibrated by the vibrating molten solder.
After the rear surface of the chip carrier 1 and the solder 5 are adjusted, the chip carrier 1 is cooled to complete the mounting.

FIG. 2 is a longitudinal sectional view of another embodiment of the present invention. In this embodiment, a chip carrier 1 is used in which a metal plate 11 made of the same tantalum plate having a thickness of about 0.6 mm and a dielectric substrate layer 12 made of alumina or the like having a thickness of about 0.25 mm are brazed. The recess 13 is formed by the metal plate 11 made of the same tantalum plate as the alumina substrate layer 12 without the layer 12. A gold-tin solder 5 having a thickness of 0.3 μm and a semiconductor pellet 6 having a thickness of about 60 μm are placed in the recess 13, and the chip carrier is placed on a heating table. Hereinafter, the first
In the same manner as in the embodiment of the figure, a nitriding gas stream pressure-modulated in a pulsed manner at the time of melting of the solder is jetted onto the semiconductor pellet, and the chip carrier is cooled when the solder has spread to the copper tantalum surface of the pellet carrier 1 and the back surface of the semiconductor pellet. And
Complete the mount.

In the present embodiment, the chip carrier concave portion 13 which is a mount portion
Accordingly, there is an advantage that the mounting position of the semiconductor pellet can be determined.

〔The invention's effect〕

As described above, the semiconductor pellet mounting method according to the present invention generates vibrations in the semiconductor pellets and the molten solder by applying a pulsed air pressure modulated airflow to the semiconductor pellets to be mounted, and the vibrations cause the chip carrier and the semiconductor pellets. You can mount it by blending the back with the solder. In this mounting method, there is no need to scrub the semiconductor pellets at the time of mounting, so that no extra area is required for scrubbing. Further, unlike the case of scrubbing with tweezers or the like, there is no fear of causing chipping or cracking of the pellet during scrubbing.
Also, there is an advantage that a good mounting state can be obtained even when mounting is performed on a concave portion having no scrub area.

[Brief description of the drawings]

FIG. 1 (a) is a longitudinal sectional view of one embodiment of the present invention, FIG. 1 (b) is a graph showing the state of air flow jet pressure ejected from a nozzle, and FIG. 2 is another embodiment of the present invention. It is a longitudinal section of an example. DESCRIPTION OF SYMBOLS 1 ... Chip carrier, 2 ... Dielectric substrate, 3 ... Conductor layer, 4 ... Heating table, 5 ... Solder, 6 ... Semiconductor pellet, 7 ... High pressure nitrogen tube, 8 ... Gas heating device , 9 ...
... Pressure adjusting device, 10 ... Nozzle, 11 ... Metal plate, 12
... Dielectric substrate layer, 13... Recess (mounting portion).

Claims (3)

(57) [Claims] 1. A chip carrier is placed on a heating table, a solder is placed on the chip carrier, and a semiconductor pellet is placed on the solder. The chip carrier, the solder, and the semiconductor pellet are heated to a melting point of the solder. In a semiconductor pellet mounting method in which the solder is melted and then cooled to braze the semiconductor pellet on the chip carrier, the pellet and the molten solder are added by applying a pulsed airflow to the semiconductor pellet during the melting of the solder. And mounting the semiconductor pellet on the chip carrier by vibrating the semiconductor pellet. 2. The method according to claim 1, wherein the pulsed airflow is an airflow made of a heated gas. 3. A heating table on which a chip carrier is mounted, a gas heating device for heating gas, and a semiconductor heating device mounted on the chip carrier mounted on the heating table via a solder. A semiconductor pellet mounting device comprising: a jet nozzle for jetting a gas heated by a gas heating device; and a pressure adjusting device for guiding the gas heated by the gas heating device to the jet nozzle. Is a semiconductor pellet mounting apparatus, wherein the pressure of the gas heated by the gas heating device is modulated in a pulsed manner, whereby the gas ejected from the nozzle is converted into a pulsed airflow.