Semiconductor device-manufacturing method for manufacturing...

Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Packaging or treatment of packaged semiconductor

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C438S064000

Reexamination Certificate

active

06797530

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-290727, filed Sep. 25, 2001, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device-manufacturing method, particularly to a heat-radiating step.
2. Description of the Related Art
Usually, a semiconductor device-manufacturing method includes a die-mount step and a connection step. In the former step semiconductor elements are die-mounted on lead frames, and in the latter step the electrodes of the semiconductor elements and lead frames are connected through metal wires.
FIG. 8
illustrates the outline of a semiconductor device-manufacturing method wherein the die-mount step mentioned above is a solder vapor-depositing step. In this method, solder
51
is vapor-deposited on the reverse side
52
a
of a semiconductor conductor wafer
52
in order to form unseparated semiconductor elements
53
. The semiconductor elements
53
are separated by dicing the semiconductor conductor wafer
52
along predetermined lines. Then, the semiconductor elements
53
are mounted on lead frames
54
, and the electrodes of the semiconductor elements and the lead frame
54
are connected through metal wires
55
, thereby fabricating semiconductor devices
56
.
FIG. 9
illustrates the outline of the semiconductor device-manufacturing method wherein the die-mount step mentioned above is a solder pre-coat step. In this method, fused solder
51
is supplied onto lead frames
54
, and semiconductor elements
53
formed by dicing the semiconductor conductor wafer
52
are scrub-mounted on the fused solder
51
. Then, the connection step is carried out to connects the electrodes of the semiconductor elements
53
to the lead frames
54
by means of metal wires
55
, thus fabricating semiconductor devices
56
. The “scrub-mounting” is intended to refer to an operation of scrubbing the semiconductor elements
53
and the lead frames
54
against each other in such a manner as to spread the fused solder
51
, for joining.
The semiconductor device-manufacturing methods described above have the following problems. That is, when wire bonding is utilized, a semiconductor element is first die-mounted on a lead frame, and then a metal wire is connected to the lead frame. Because of this procedure, the metal wire forms a loop in the region surrounding the semiconductor element, and a dead area is inevitably produced. To be more specific, the land the lead frame has for connection has to be spaced from the semiconductor element more than a predetermined distance. In addition, since the loop is formed from the terminal, a margin corresponding to the height of the loop is needed. As can be seen from this, the conventional methods impose restrictions on the miniaturization of semiconductor devices.
As a method of connecting a lead frame and a semiconductor element without using a wire, connection by flip chip bonding is proposed. In flip chip bonding, bumps are formed on the bonding pads of a semiconductor element, for alignment with the lead frame, and the solder reflow based on the application of heat or ultrasonic vibration executed in a pressure-applied state is utilized for connection.
The manner in which solder is supplied in the die-mount step will be considered. Where the die-mount step is the solder vapor-depositing step, a long time is required for supplying the solder to the reverse side of a semiconductor element. On the other hand, where the die-mount step is the solder pre-coat step, the fused solder cannot be supplied at high speed.
A semiconductor device manufactured in the manufacturing methods described above will be looked at in light of thermal design. Even if a semiconductor device is provided with a heat sink (metal plate)
61
, this heat sink
61
is within those portions of sealing resin
62
which are located near a semiconductor element
53
, as shown in FIG.
10
. With this structure, heat is radiated mainly to a substrate
63
after passing by way of the lead frame
54
and the sealing resin
62
, as indicated by arrows “H” in FIG.
10
. It is therefore impossible to expect a high heat radiation efficiency.
Recently-developed semiconductor elements are highly integrated and operate at high speed, and therefore generate a large amount of heat. In addition, they have to be arranged at high density since recent electronic devices are very small. As long as the heat sink is embedded within the sealing resin, the semiconductor element may not maintain a normal operating temperature (which depends upon the type of semiconductor element and is normally lower than 80° C. or so), adversely affecting the reliability of the semiconductor element.
BRIEF SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide semiconductor device-manufacturing method for manufacturing semiconductor devices which are approximately the same in size as semiconductor elements and which have an improved heat radiating efficiency.
To solve the problems and to attain the object, the present invention provides semiconductor device-manufacturing methods described below.
A semiconductor device-manufacturing method comprising: a laminated wafer formation step of placing a semiconductor wafer in such a manner that a side having no electrode and no electronic circuit faces a solder material, then laying a metal plate on that side of the semiconductor wafer with a solder material interposed, and then causing the metal plate and the wafer to form a one-piece structure by decompression pressing, thereby obtaining a laminated wafer; and a dicing step of dicing the laminated wafer to form laminated chips.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.


REFERENCES:
patent: 6504096 (2003-01-01), Okubora
patent: 6521485 (2003-02-01), Su et al.
patent: 2000-3985 (2000-01-01), None
patent: 2000-77576 (2000-03-01), None

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Semiconductor device-manufacturing method for manufacturing... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Semiconductor device-manufacturing method for manufacturing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device-manufacturing method for manufacturing... will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-3235367

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.