Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board
Reexamination Certificate
2000-07-07
2002-10-29
Clark, Jasmine J B (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
On insulating carrier other than a printed circuit board
C257S723000, C257S783000, C257S797000
Reexamination Certificate
active
06472726
ABSTRACT:
TECHNICAL FIELD
This invention relates to a semiconductor device and a method of fabrication thereof, together with a semiconductor module, a circuit board, and electronic equipment.
BACKGROUND ART
One result of the recent miniaturization of electronic equipment is a demand for semiconductor device packages that can be used for high-density mounting. To address this demand, surface-mount packages such as a ball grid array (BGA) or chip scale/size package (CSP) have been developed. Surface-mount packages make it possible to use a substrate on which is formed an interconnecting pattern to be connected to semiconductor chips.
However, it is difficult with surface-mount packages in the prior art to improve the reliability and productivity, because the connections between the semiconductor chips and the interconnecting pattern are done by an alloy such as solder.
The present invention was devised in order to solve the above problems in the art. The objective thereof is to provide a method of fabricating a semiconductor device that has superior reliability and productivity, together with a semiconductor device formed by this method, a semiconductor module, a circuit board, and electronic equipment.
DISCLOSURE OF THE INVENTION
(1) A method of fabricating a semiconductor device in accordance with this invention comprises the steps of: affixing semiconductor chips by an adhesive to a tape carrier on which are formed bonding portions in a matrix; connecting electrodes formed on the semiconductor chips electrically to the bonding portions; and dividing the tape carrier into individual units for each of the semiconductor chips.
In this invention, bonding portions are any portions for connection to individual semiconductor chips, and could comprise lands for connecting electrodes of the semiconductor chips, lands for forming external electrodes, or wiring for connecting these lands, by way of example. These bonding portions are provided on the substrate and they do not protrude into device holes.
In this aspect of the invention, a plurality of bonding portions are formed across the width of the tape carrier and a plurality of semiconductor chips are connected thereto. This makes it possible to mount a plurality of semiconductor chips across the width of the tape carrier, so that a large quantity of semiconductor devices can be fabricated.
(2) This method of fabricating a semiconductor device may further comprise a step of forming a plurality of external electrodes on the tape carrier.
(3) In this method of fabricating a semiconductor device, the step of dividing the tape carrier into individual units may involve stamping the tape carrier into individual units.
(4) In this method of fabricating a semiconductor device, electrically conductive particles may be dispersed within the adhesive, whereby the bonding portions and the semiconductor chips are electrically connected.
The bonding portions and the electrodes are electrically connected by the electrically conductive particles in this aspect of the invention, making it possible to fabricate semiconductor devices by a method that has superior reliability and productivity.
(5) In this method of fabricating a semiconductor device, the adhesive may be interposed between the bonding portions and surfaces of the semiconductor chips bearing the electrodes, then pressure may be applied between the semiconductor chips and the tape carrier, whereby connections between the electrodes formed on the semiconductor chips and the bonding portions are performed via the electrically conductive particles.
(6) In this method of fabricating a semiconductor device, the tape carrier may be unwound from a reel, and the tape carrier may be wound onto another reel while the execution of at least one of the steps of the method, in preparation for a next step.
Since this ensures that each step can be performed in a reel-to-reel manner, it makes it possible to fabricate the semiconductor devices smoothly.
(7) In this method of fabricating a semiconductor device, at least one of the steps of this method may be performed after a step of cutting the tape carrier into rectangular substrates of a length comprising a plurality of the bonding portions in the longitudinal direction of the tape carrier.
Since this enables a step or steps to be performed on the rectangular substrate, this is more efficient for short production runs than steps performed during reel-to-reel processing.
(8) In this method of fabricating a semiconductor device, identification marks may be formed in the tape carrier, for delimiting the bonding portions at positions within regions at which the tape carrier is to be cut into the rectangular substrates.
This configuration makes it possible to easily identify the cutting positions when the tape carrier is cut into rectangular substrates.
(9) In this method of fabricating a semiconductor device, the step of cutting the tape carrier into rectangular substrates may be performed before the semiconductor chips are affixed to the tape carrier; and the tape carrier may be cut on widthwise lines of the bonding portions that are the (integer n×constant d)th widthwise lines of the bonding portions in the longitudinal direction, with any one line of the bonding portions across the width of the tape carrier acting as a base line.
This ensures that a usable tape carrier is used, even if it is not cut into rectangular substrates. The tape carrier is cut on bonding portions at predetermined positions. In this case, since the tape carrier is cut on the bonding portions, wider cutting regions can be ensured than in a case in which the tape carrier is cut between adjacent bonding portions. As a result, not only is the cutting operation facilitated, but no stress is imparted to the remaining bonding portions on the rectangular substrate during the cutting, enabling an improvement in the yield.
(10) In this method of fabricating a semiconductor device,
the step of affixing the semiconductor chips to the tape carrier may be performed before the step of cutting the tape carrier into rectangular substrates;
the semiconductor chips may be mounted on the bonding portions, except for the bonding portions in the (integer n×constant k)th widthwise lines of the bonding portions in the longitudinal direction, with any one line of the bonding portions across the width of the tape carrier acting as a base line; and
the tape carrier may be cut on widthwise lines of interconnecting pattern that are the (integer n×constant d)th (where k≦d) widthwise lines of the interconnecting pattern in the longitudinal direction from the base line.
The tape carrier is cut into rectangular substrates after the semiconductor chips are mounted thereon, so this configuration ensures that there are no semiconductor chips mounted at the cutting positions. The tape carrier is cut on the bonding portions where there are no semiconductor chips. Since the tape carrier is cut on the bonding portions, it is possible to ensure wider cutting regions than if the tape were cut between adjacent bonding portions. As a result, not only is the cutting operation facilitated, but no stress is imparted to the remaining bonding portions on the rectangular substrate during the cutting, enabling an improvement in the yield.
(11) In this method of fabricating a semiconductor device,
the bonding portions may be formed on the tape carrier, except for widthwise lines of regions for the formation of the bonding portions that are the (integer n×constant k)th widthwise lines of the regions for the formation of the bonding portions in the longitudinal direction, with any one line of the region for the formation of the bonding portions acting as a base line;
the step of cutting the tape carrier into rectangular substrates may be performed before the semiconductor chips are affixed to the tape carrier, and
the tape carrier may be cut on widthwise lines of the regions for the formation of interconnecting pattern that are the (integer n×constant d)th (where k≦d) widthwise lines of the regions for the f
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