Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Including adhesive bonding step
Reexamination Certificate
2000-09-11
2003-06-24
Pert, Evan (Department: 2829)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Including adhesive bonding step
C438S120000, C438S126000
Reexamination Certificate
active
06582993
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of underfilling a semiconductor device such as a flip-chip mounted on the surface of a wiring substrate.
2. Description of the Prior Art
A conventional method of underfilling a semiconductor device comprises, or example, supplying a fluid of an underfill material, such as an ultraviolet (UV) curable reaction resin or a thermosetting resin, on the up-faced surface of a wiring substrate prior to setting of the semiconductor device upon the up-faced surface of the wiring substrate. The semiconductor device is placed on the fluid of the underfill material swelling on the up-faced surface of the wiring substrate. The underfill material is then subjected to a curing treatment while the semiconductor device is urged against the up-faced surface of the wiring substrate. The semiconductor device is thus fixed on the up-faced surface of the wiring substrate. According to this type of method, the space remaining between the set semiconductor device and the tip-faced surface of the wiring substrate is expected to completely he filled with the fluid of the underfill material, without any voids, even if the space gets smaller between the semiconductor device and the wiring substrate.
The supplied amount of the fluid needs to be accurately controlled for the individual semiconductor devices in the aforementioned method of underfilling. If the fluid is supplied too much for a semiconductor device, the fluid is allowed to overflow out of the space between the semiconductor device and the up-faced surface of the wiring substrate. The overflowing fluid may hinder the subsequent treatment or process for the wiring substrate or printed circuit board. To the contrary, if the fluid is not supplied enough, metallic input/output bumps may not be fully contained within the underfill material between the semiconductor device and the wiring substrate. In this case, a wiring pattern on the wiring substrate may not be fully covered with the underfill material between the semiconductor device and the wiring substrate. In any event, exposure of the input/output bumps and the wiring pattern may induce corrosion of the bumps and the wiring pattern, which is not preferable.
In addition, the individual semiconductor devices need to be separately subjected to a curing treatment in the aforementioned method of underfilling. A longer time should be spent for mounting the semiconductor devices on the corresponding wiring substrate. Moreover, the semiconductor device needs to be kept urged against the up-faced surface of the wiring substrate when the fluid of the underfill material is to be cured. A complicated mechanism should be employed in an underfilling apparatus accomplishing the above-mentioned method of underfilling.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a method of underfilling a semiconductor device capable of accurately controlling the supplied amount of an underfill material to the utmost, and an underfilling apparatus for a semiconductor device capable of realizing the same method.
It is another object of the present invention to provide a syringe, a printed circuit board and a method of preliminary treatment all designed to contribute to an accurate control of the supplied amount of the underfill material.
It is a further object of the present invention to a method of underfilling, a semiconductor device capable of employing an underfilling apparatus of a relatively simplified structure even if an underfill material is supplied to the surface of a wiring substrate prior to setting of the semiconductor device on the surface of the wiring substrate.
According to a first aspect of the present invention, there is provided a method of underfilling a semiconductor device, comprising: supplying a fluid of a reaction resin from a nozzle toward a surface of a wiring substrate prior to setting of the semiconductor device upon the surface of the wiring substrate; and reducing a fluidity of the fluid within the nozzle when a predetermined amount of the fluid has been discharged.
When the fluidity of the fluid is reduced in the nozzle, a partial fluid of the reduced fluidity can be obtained to define a partition mass or segment in the fluid within the nozzle. A reliable split can thus be achieved between the partition mass and the fluid discharged from the tip end of the nozzle. The split can be utilized to control the supplied amount of the fluid at a higher accuracy. The reaction resin may include a light curable reaction resin which is hardened by radiation of alight, a thermosetting resin which is hardened by heat, and the other types of reaction resins.
According to a second aspect of the present invention, there is provided a method of underfilling a semiconductor device, comprising: supplying a fluid of a light curable reaction resin from a nozzle toward a surface of a wiring substrate prior to setting of the semiconductor device upon the surface of the wiring substrate; and irradiating the fluid of the light curable reaction resin through a transparent window defined in the nozzle when a predetermined amount of the fluid has been discharged.
When the fluid within the nozzle is irradiated through the transparent window, a hardening reaction is induced in the irradiated segment of the fluid. The reduction in the fluidity can be achieved in the irradiated segment of the fluid. The irradiated segment forms a partition mass in the fluid within the nozzle in the aforementioned manner. A reliable split can thus be achieved between the partition mass and the fluid discharged from the tip end of the nozzle. The split can be utilized to control the supplied amount of the fluid at a higher accuracy. The ultraviolet ray curable reaction resin may include one which is hardened by independent radiation of an ultraviolet ray, one which is hardened by radiation of an ultraviolet ray in combination with heat, and the like.
For example, the aforementioned method may employ a syringe comprising: an opaque nozzle having a port at the tip end; an opaque container connected to the root end of the nozzle and containing a fluid of a light curable reaction resin; and a transparent window defined in the nozzle. The syringe is allowed to discharge the fluid of the light curable reaction resin from the port at the tip end in response to a pressure or the like applied to the container. When the window is irradiated, the fluidity of the fluid can be reduced in response to the irradiation in the aforementioned manner.
In place of the above-described syringe, a conventional syringe can be employed which comprises an opaque nozzle having a port at the tip end and an opaque container connected to the root end of the nozzle and containing a fluid of a light curable reaction resin, as conventionally known. In this case, a tube attachment may be coupled to the tip end of the nozzle. A transparent window is defined in the tube attachment. The fluid discharged from the nozzle is designed to pass through the tube attachment so as to flow out of the tip end of the tube attachment. When the fluid within the tube attachment is irradiated through the transparent window, the reduction in the fluidity can be achieved in the irradiated segment of the fluid in the aforementioned manner. The attachment is adapted to achieve reduction in the fluidity of the fluid without re-designing the structure of conventional syringes.
In addition, the aforementioned method may employ an underfilling apparatus for a semiconductor device, comprising: a table; a support head opposed to the table; a positioning mechanism connected to the support head so as to induce movement of the support head toward a discharge position; a dispenser connected to the support head so as to supply a pressure to the support head, and a light source designed to irradiate a predetermined irradiation area defined between the support head at the irradiation position and the table. The aforementioned syringe can be mounted on or attached to the suppor
Baba Shunji
Kainuma Norio
Kira Hidehiko
Kobae Kenji
Armstrong Westerman & Hattori, LLP
Pert Evan
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