U.S. patent number 3,780,429 [Application Number 05/211,277] was granted by the patent office on 1973-12-25 for method for manufacturing a base for the envelope of an electric component.
This patent grant is currently assigned to U.S. Philips Corporation. Invention is credited to Gerardus Cornelis Marie Benschop, Hendrikus Johannes Christianus Friebel, Simon Jonker.
United States Patent |
3,780,429 |
Friebel , et al. |
December 25, 1973 |
METHOD FOR MANUFACTURING A BASE FOR THE ENVELOPE OF AN ELECTRIC
COMPONENT
Abstract
A method of manufacturing a base for the envelope of an electric
component, for example a semiconductor device, in which a pressure
member is provided on one side in the cavity of a jig, which cavity
has an approximately rectangular cross-section, after which a
member of insulating material which softens upon heating is placed
on the pressure member from the other side where a chamber of a
larger cross-section is present which communicates with the cavity,
after which of a conductor grid the conductors of which are
supported at one end by a strip and are bent at their other end
transverse to the plane of the grid the ends connected to the strip
are inserted into a narrow slot between the pressure member and the
wall of the cavity until the bent ends of the conductors bear on
the insulating member after which the chamber is closed by a
closure plate, the jig is heated and a force is exerted via the
pressure member, in which the bent ends of the conductors are
forced against the closure plate by the insulating member and a
part of the softened insulating material is forced between the
conductors in the direction of the side walls of the chambers so
that a base is formed the bent ends of which of the conductors are
situated on the upper side of the insulating member and the parts
of the conductors connected thereto with are embedded in the
insulating material and the further part of the conductor project
from the lower side of the insulating member.
Inventors: |
Friebel; Hendrikus Johannes
Christianus (Nijmegen, NL), Jonker; Simon
(Emmasingel, Eindhoven, NL), Benschop; Gerardus Cornelis
Marie (Nijmegen, NL) |
Assignee: |
U.S. Philips Corporation (New
York, NY)
|
Family
ID: |
19812245 |
Appl.
No.: |
05/211,277 |
Filed: |
December 23, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Jan 13, 1971 [NL] |
|
|
7100410 |
|
Current U.S.
Class: |
29/848; 29/831;
65/140; 29/827; 65/59.34; 257/E23.19; 257/E23.044 |
Current CPC
Class: |
H01L
23/055 (20130101); H01L 23/49562 (20130101); H01L
2924/00 (20130101); Y10T 29/49121 (20150115); H01L
2924/01079 (20130101); Y10T 29/49128 (20150115); Y10T
29/49158 (20150115); H01L 2924/0002 (20130101); H01L
2924/0002 (20130101) |
Current International
Class: |
H01L
23/48 (20060101); H01L 23/495 (20060101); H01L
23/02 (20060101); H01L 23/055 (20060101); H01b
013/14 () |
Field of
Search: |
;29/626,627
;65/DIG.7,54,59,138,139,140,102,319,320,321 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lanham; Charles W.
Assistant Examiner: Walkowski; Joseph A.
Claims
What is claimed is:
1. A method for making a base for an electric component, comprising
the steps of:
forming conductive strips each having a transversely bent over
portion near one end thereof;
spacing the strips around a block of heat softenable insulating
material having a top surface, a bottom surface, and a side
surface, each strip extending along the side surface to and beyond
the bottom surface with the bent over portion partially covering
the top surface;
heating the block of insulating material until suitably soft;
while the block is soft, compressing the block between a first
solid surface covering the top surface of the block and a second
surface covering the bottom surface of the block, whereby the bent
over portion of each strip is pinched and held between the first
surface and the top surface of the block while soft insulating
material from the side of the block is squeezed through the spaces
between the strips; and
molding to a suitable shape the soft insulating material which
squeezes through the spaces between the strips.
2. The method of claim 1 wherein the forming step comprises forming
a grid of parallel spaced conductive fingers having a transversely
bent over portion near one end thereof.
3. The method of claim 2 wherein the spacing step comprises
positioning the grid adjacent a block of heat softenable insulating
material having a top surface, a bottom surface, and a side
surface, the grid extending along the side surface to and beyond
the bottom surface with the bent over portion partially covering
the top surface.
4. The method of claim 1 wherein the molding step includes
maintaining the position of the strips.
5. The method of claim 1 wherein the compressing step includes
maintaining the position of the strips.
6. The method of claim 1 wherein the insulating material is glass.
Description
The invention relates to a method of manufacturing a base for the
envelope and an electric component, for example a semiconductor
device.
There are known various methods of manufacturing a base for a
semiconductor device, for example an integrated circuit or a thin
film or thick film circuit, in which a flat grid of metal
conductors is used. According to a known method, the grid is
clamped between a lower part and an upper part of a jig, while a
pre-shaped glass member is provided in a cavity of the jig. After
heating the jig, the glass member is forced in the shape determined
by the cavity. The flat conductors project from the side walls of
the thus shaped base. So in this base, no metal base cap which
surrounds the side walls can be used so that the base may be
vulnerable.
Semiconductor bases are also known having a circular cross-section
in which a glass insulating member is incorporated in a metal base
cap and through which a number of conductor wires are passed.
During the manufacture pre-shaped glass insulating members are used
which are provided with apertures through which the conductor wires
are passed. The conductor wires are fixed mutually by means of
apertures present in a matrix. The heated glass in the matrix
cavity adheres to the metal base cap and the conductor wires are
sealed simultaneously. Conductors incorporated in a grid cannot be
used.
It is the object of the invention to provide a method of
manufacturing a base for an electric component, for example a
semi-conductor device, which has a flat and box-shaped
construction, which has only small dimensions and in which a grid
of conductors can be used which projects from the lower side of the
base. The method according to the invention is characterized in
that a pressure member is provided in a mould having a cavity of
approximately rectangular cross-section, which pressure member
closes the cavity on one side for the greater part, after which a
member of an insulating material which softens upon heating is
placed on the pressure member from the other side where a chamber
of a larger cross-section is present which communicates with the
cavity, that a conductor grid is used the conductors of which are
supported at one end by a strip and are bent transverse to the
plane of the grid at their other end, the ends connected to the
strip being inserted into a narrow slot between the pressure member
and the wall of the cavity and the bent ends of the conductors
bearing on the insulating member, the chamber being then closed by
a closure plate, the mould being heated and a force being exerted
via the pressure member, so that the bent ends of the conductors
are forced against the closure plate by the insulating member and a
part of the softened insulating member is forced between the
conductors in the direction of the side walls of the chamber so as
to form a base with the bent ends of the conductors situated on the
upper side of the insulating member, the parts of the conductors
connected thereto embedded in the insulating member and the further
part of the conductors projecting from the lower side of the
insulating member.
In a preferred embodiment of the method according to the invention
a metal base cap which is open on the lower and upper sides is
placed in the chamber after providing the grid of conductors and
the upper side of the base cap is closed by the closure plate, the
part of the softened insulating member forced between the
conductors moving in the direction of the wall of the base cap and
a hermetic connection being formed between the base cap and the
insulating member. By the use of a metal base cap, a mechanically
rigid base is obtained, The upper side of the base cap may be
shaped so that the connection of a lid by means of a welding
operation can simply be carried out, there being sufficient space
for the welding electrodes.
The member of insulating material used preferably is a crystallised
or non-crystallised glass.
The conductors are preferably incorporated in a grid comprising a
rectangular frame in which two oppositely located sides of the
frame constitute the strips which support two series of conductors
present inside the frame, the grid being bent to approximately
U-shape so that rows of conductors are formed which coincide with
the limbs of the U and the bent ends coincide with the connection
member of the limbs of the U.
With this method it is possible to simultaneously manufacture a
number of bases in a mould. For that purpose a mould is used having
a number of aligned cavities and use is made of a series of
conductor grids which are connected together and which are
constituted by one strip of metal, the connection place of adjacent
frames of the series being situated in the part of the frames which
coincides with the connection member of the limbs of the U,
centering apertures being present in said parts of the frames for
centering the grids in the mould.
The invention also relates to a device for the series production of
bases for electric components, for example semiconductor devices.
According to the invention, such a device is characterized in that
it is constructed from a sealing block, a closure plate and
pressure members, the sealing block comprising a number of rows of
mainly rectangular cavities which at one end have a chamber of a
larger cross-section, the sealing block being closable on the side
of the chambers by the closure plate and the pressure members being
introduced into the cavities on the oppositely located side, each
cavity being bounded on one side by two spaced-apart upright dams
extending in the direction of the width of the mould and on the
other side by upright ridges present between the dams and forming
part of cross beams, a clearance which exists between the pressure
members introduced into the cavities and the dams of the matrix
cavities having a value which exceeds the thickness of the grid of
conductors to be used only to a slight extent. The structure of
such a mould is comparatively simple. As a result of the small
clearance between the dams and the pressure members where the grid
of conductors is to be located, a larger resistance prevails at
that area against the penetration of material of the insulating
member so that the conductors are not covered with said material at
said area.
According to one embodiment, longitudinal slots and transverse
slots extending at right angles thereto are present in the sealing
block, the dams being constituted by upright parts situtated
between the longitudinal and transverse slots, the cross beams
being secured in the transverse slots in such manner that the
ridges constitute a boundary in the longitudinal slots, the sealing
block comprising apertures in which the pressure members are
movable.
According to another embodiment, the sealing block is constructed
from interconnected continuous longitudinal and cross beams, said
continuous longitudinal beams being arranged at mutually equal
distances and comprising equally spaced recesses on the side of the
closure plates in which the cross beams fit in such manner that the
upright ridges are situated between two continuous longitudinal
beams, the width of the ridges being smaller than the distance
between the longitudinal beams to obtain a slot for receiving the
conductor grid.
The invention also relates to a base for the envelope of an
electric component, for example, a semiconductor device, in which
the base has a box-shaped construction and comprises flat electric
conductors which are formed from a grid of conductors. According to
the invention, such a base is characterized in that the side walls
consist of a metal base cap which is closed at one end by an
insulating member and comprises at its other end a projecting edge
which forms a connection part for a lid, the flat current
conductors comprising at one end a portion which is bent transverse
to their longitudinal direction and which is situated on the upper
side of the insulating member, the conductors being passed further
through the insulating member and projecting therefrom on the lower
side.
The flat conductors are preferably situtated in two rows, the bent
ends of the conductors of the two rows facing each other.
In order that the invention may be readily carried into effect, a
few examples thereof will now be described in greater detail, by
way of example, with reference to the accompanying drawings, in
which
FIG. 1 shows diagrammatically the filled mould
FIG. 2 shows diagrammatically the parts with which the mould is
filled
FIG. 3 shows diagrammatically the formation of the base
FIGS. 4 to 6 are a cross-sectional view, a plan view and a
longitudinal sectional view, respectively, of a preferred
embodiment of the base according to the invention
FIG. 7 shows a grid of conductors to be used for the base
FIG. 8 is a perspective elevation of a part of a mould in the
fillling position
FIG. 9 is a sectional view of a part of the mould
FIG. 10 is a perspective view of a part of another mould.
FIGS. 1, 2 and 3 show by way of example the manufacture of a base
which has proved to be particularly suitable for a hermetic
envelope of a semiconductor device. A sealing block 1 comprises a
cavity 2 of approximately rectangular cross-section which opens
into a chamber 3 having a larger cross-section. On a pressure
member 4 provided in the matrix cavity 2 a moulding 5 of, for
example, sintered glass is placed (see FIGS. 1 and 2). The moulding
comprises a recess 6 in which a metal plate 7 is laid which serves
to secure a semiconductor crystal afterwards. In the narrow slots
between the wall of the cavity 2 and the pressure member 4 flat
conductors 8 formed from a metal strip are inserted. FIG. 2 shows
diagrammatically said conductors incorporated in a grid. A
connection strip 9 connects the conductors at one end. The other
ends 10 are bent and bear on the moulding 5. FIG. 2 shows one of
two separate rows of conductors 8 which are each connected to a
strip 9. It is also possible, for example, to incorporate all the
conductors in a frame as is shown in FIG. 7. A base cap 11 is then
placed in the chamber 3 after which the cavity is closed by a
closure plate 12. FIG. 2 is a diagrammatic perspective elevation of
the pressure member 11, the moulding 5, the plate 7, the conductor
grid 8, 9, 10 and the base cap 11.
After filling the mould, it is turned upside down as is shown in
FIG. 3, the pressure member 4 is loaded, for example by a weight,
and the mould is placed in a furnace. The glass moulding 5 is
softened as a result of the temperature prevailing in the furnace.
The loaded pressure member 4 exerts pressure on the moulding as a
result of which on the one hand the bent ends 10 of the conductors
and the plate 7 tightly pressed against the closing plate 12 and on
the other hand a part of the softened moulding is forced between
the conductors into the chamber 3. The moulding 5 has such a
thickness that the whole chamber 3 is filled, a glass insulating
member adhering to the base cap 11 being formed and the conductors
being embedded therein. The upper side of the bent parts 10 of the
conductors remain uncovered as well as the upper side of the plate
7 sealed in the insulating member. Especially as a result of the
conductors projecting from the lower side of the base, sufficient
space is available for the welding electrodes so that it is
possible to weld a lid to the base cap. This welding is very
favourable.
The slot distance between the pressure member and the wall of the
matrix cavity is maintained so small that the insulating material
of the softened moulding 5 during pressure is not forced upwards in
the slots and, consequently, does not cover the conductors at that
area. Therefore no measures need be taken to seal the space between
the conductors which are present in the slot, so that the jig can
structurally be simple and no restrictions are imposed upon the
shape of the conductors.
It is not necessary to use the metal base cap 11. As a material for
the insulating member is to be considered first of all a
crystallized or non-crystallized glass. Other materials, however,
for example a synthetic resin, may also be used. are
FIGS. 4 to 6 show an embodiment of a base for a hermetically sealed
semi-conductor device which is particularly favourable to
manufacture. A glass insulating member 16 through which conductors
17 are passed is present in a metal base cap 15. The ends 18 of the
conductors in this embodiment are embedded in the upper side of the
insulating member 16; the other ends project from the lower side of
the base and are preferably at a standarized distance to secure
them in apertures of a mounting panel. If necessary, the conductors
17 may be bent for this purpose as is denoted in broken lines. A
recess 19 is present in the upper side of the insulating member 16.
A metal plate 20 is incorporated in said recess. A semiconductor
element can be secured to the plate 20. Contact places on the
semiconductor element may be connected, for example by means of
gold wires, to the ends 18 of the conductors 17. However, it is
also possible to connect the semiconductor element directly to the
conductors by means of the direct contact method. In that case the
plate 20 may be omitted. The conductor ends 18 must of course be
situated in the correct pattern for direct contact connection. The
upper side of the base cap 15 is provided with a flared flange 22.
A metal cover can be secured to said flange 22 in a simple manner,
preferably be welded, in which a qualitatively very good hermetic
envelope is obtained. Welding the lid to the base cap 15 presents
great advantages over other connection methods, for example
soldering. The welding connection can be carried out very rapidly,
the cost of manufacture is low and the semiconductor element
remains cold during welding. As a result of the conductor
projecting on the lower side of the base and by providing the
flange it is possible to weld in a simple conventional manner, heat
evolution occurring only at the area of the flange and the lid.
Instead of a flared flange on the base cap, the lid may be provided
with the same effect with a flange projecting to the upper side. If
desirable, any other connection method for the lid may of course
also be used.
FIG. 7 is a slightly diagrammatic example of the conductors for a
base shown in FIGS. 4 to 6 which conductors are incorporated in a
grid 24. The conductors 17 are, for example, etched or punched from
a metal strip and during the manufacture of the base they remain
connected to a frame 23 and thus maintain their mutual desirable
positions. The grid 24 is bent along the line a--a to a U-shape and
in that shape it is sealed in the insulating member during the
manufacture of the base. When the base is ready, the superfluous
frame is removed by clipping the conductors along the lines b--b.
When several bases are manufactured simultaneously in a matrix,
grids are preferably used which are united by means of a connection
member 25. This connection member is situated between the lines
a--a. An aperture 26 for centring the grids in the mould may be
present in the connection member. Such an embodiment has the
important advantage that the grid is flexible so that during the
sealing of the insulating member the differences in expansion
between the grid and the matrix can easily be compensated for.
The base described with reference to FIGS. 4 to 6 may have a
different construction at various points. For example, instead of a
glass insulating member, a synthetic resin may be used. The recess
19 in the upper side of the insulating member may be omitted. The
plate 20 may form a part of the grid; if desirable, it may also be
omitted. The conductors projecting from the bottom preferably have
the shape shown, in which the thickenings can abut against an
apertured mounting panel. However, a different shape may also be
chosen.
FIG. 8 shows an embodiment of a part of a jig for the series
production of the base shown in FIGS. 4 to 6 namely in the position
of filling the mould, compare FIG. 1. The mould mainly comprises a
closure plate 30, a sealing block 31, and pressure members 32 which
can be passed through the sealing block.
The sealing block is constituted by a graphite block in which
longitudinal and transverse grooves are provided so that dams 36
are formed. The sealing block thus obtains the shape of a plate
from which the dams 36 project. Between the dams 36, apertures 40
are present in the sealing block 31 through which the pressure
members 32 can be passed. In order to obtain matrix cavities in
which the glass can enter under the pressure of the pressure
members 32 without laterally flowing in the longitudinal and
transverse grooves, cross beams 37 are secured in the transverse
grooves and are provided with ridges 38. Centering pins 42 may be
provided on the ridges 38 which pins can cooperate with the
centering apertures 26 in the connection members 25 of the
conductor grids, The chambers in which the bases are formed are
denoted by 43. Slots 41 are present between the pressure members 32
and the dams 36 (see FIG. 9) into which slots the ends of the
conductors connected to the frame can be inserted. The slots 41
leave only such a space between the pressure members 42 and the
dams 36 that during the pressure the glass is not forced into the
slots so that a sealing at that area is not necessary.
In order to obtain the base shown in FIGS. 4 to 6, the closure
plate 30 comprises bosses 45 which fall in the base caps (compare
FIGS. 1 and 3) and against which the bent ends of the conductors
engage. Bosses 46 are also present which press against the metal
plates which serve as a support for the semiconductor elements.
It will be obvious that such a structurally comparatively simple
mould is particularly suitable for the simultaneous manufacture of
a number of bases. The way of manufacturing has already been
described clearly for one base with reference to FIGS. 1 to 3. The
mould enables the use of a series of interconnected conductor grids
which can be centered relative to the cavities and which are
flexible so that deformation of the conductors does not occur.
FIG. 10 shows a part of the sealing block of a second embodiment of
the mould. This mould is extremely simple in design. It consists
preferably of parts which are manufactured from graphite. The
closure plate and the pressure members may be shaped in the same
manner as in the embodiment shown in FIG. 8. The sealing block
consists of longitudinal beams 54 and cross beams 55 which are
connected together, The cross beams have ridges 56 which may be
provided again with a centering pin 57 for centering the conductor
grids. The longitudinal beams 54 are situated each time between two
ridges 56 so that the mutual position is preferably fixed. The
parts of the cross beams 55 not provided with a ridge fall in
recesses 58 of the longitudinal beams so that their position is
also perfectly fixed. The pressure members and also the ridges
again have such dimensions that a slot of a small thickness in
which parts of the grid can fall is formed between the upright
walls of the dams and the pressure members and ridges,
respectively.
The operation of this mould corresponds entirely to the operation
of the jig shown in FIG. 8 so that this need not be further
described herein.
* * * * *