U.S. patent application number 09/164691 was filed with the patent office on 2001-11-15 for holder for a semiconductor substrate, and method of manufacturing a semiconductor device using such a holder.
This patent application is currently assigned to TYVELEIJN. Invention is credited to TYVELEIJN, JOHANNES H..
Application Number | 20010040329 09/164691 |
Document ID | / |
Family ID | 8228792 |
Filed Date | 2001-11-15 |
United States Patent
Application |
20010040329 |
Kind Code |
A1 |
TYVELEIJN, JOHANNES H. |
November 15, 2001 |
HOLDER FOR A SEMICONDUCTOR SUBSTRATE, AND METHOD OF MANUFACTURING A
SEMICONDUCTOR DEVICE USING SUCH A HOLDER
Abstract
The invention relates to a holder (10) for a semiconductor
substrate (1) comprising a main body (2) which is provided with
three or more projections (3) by means of which the substrate (1)
can be held fixed in the holder (10). Two projections (3A, 3B) are
fixedly connected, and a third projection (3C) present opposite the
other two (3A, 3B) is movably connected to the main body (2). The
third projection (3C) can be moved away from the other two (3A, 3B)
and is urged towards the latter two by means (4). According to the
invention, a lateral side (5) of each projection (3) facing towards
the substrate (1) to be inserted is provided with a convex recess
(6) whose geometry is such that exclusively the outermost edges of
both the upper surface and the lower surface of the substrate (1)
to be inserted come into contact with the convex recess (6). A
substrate (1), for example a round substrate, can be satisfactorily
fastened in such a holder (10) while still its entire surface area
can be processed. Given a suitable placement of the projections
(3), fluctuations in diameter and thickness of the substrate (1) to
be inserted are compensated for. The projections (3) have a diabolo
shape in a preferred embodiment. The accessibility of the substrate
(1) is substantially optimized by this. In addition, such a holder
(10) can be simply and inexpensively manufactured. A holder (10)
according to the invention is particularly suitable for treatments
of the semiconductor substrate (1) as part of the manufacture of
semiconductor devices such as diodes, in particular in steps such
as the provision or removal of a (semi)conducting or insulating
layer.
Inventors: |
TYVELEIJN, JOHANNES H.;
(STADSKANAAL, NL) |
Correspondence
Address: |
CORPORATE PATENT COUNSEL
US PHILIPS CORPORATION
580 WHITE PLAINS ROAD
TARRYTOWN
NY
10591
|
Assignee: |
TYVELEIJN
|
Family ID: |
8228792 |
Appl. No.: |
09/164691 |
Filed: |
October 1, 1998 |
Current U.S.
Class: |
269/297 |
Current CPC
Class: |
Y10S 269/902 20130101;
Y10S 269/903 20130101; H01L 21/68728 20130101 |
Class at
Publication: |
269/297 |
International
Class: |
B23Q 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 3, 1997 |
EP |
97203073.8 |
Claims
1. A holder (10) for a semiconductor substrate (1) comprising a
main body (2) which is provided with three or more projections (3)
between which the semiconductor substrate (1) can be fixed in the
holder (10) and of which at least a first and a second projection
(3A, 3B) are fixedly connected to the main body (2), while a third
projection (3C) which is present opposite the first and the second
projection (3A, 3B) is movably connected to the holder (10) and can
be moved in a direction away from the first and the second
projection (3A, 3B), while the holder (10) is provided with means
(4) by which the third projection (3C) is urged towards the first
and the second projection (3A, 3B), characterized in that a lateral
side (5) of each projection (3) facing towards the semiconductor
substrate (1) to be inserted is provided with a convex recess (6)
whose geometry is such that exclusively the outermost edges of the
both the upper surface and the lower surface of the semiconductor
substrate (1) to be inserted come into contact with said convex
recess (6).
2. A holder (10) as claimed in claim 1, characterized in that the
recess (6) has the shape of a triangle or a trapezium, seen in
cross-section, and preferably the shape of a triangle.
3. A holder (10) as claimed in claim 1 or 2, characterized in that
the projections (3) have the shape of a diabolo (3), preferably a
diabolo (3) which has the shape of two truncated cones (31, 32)
placed on one another.
4. A holder (10) as claimed in claim 3, characterized in that the
upper cone (31) of each diabolo-shaped projection (3) has a smaller
apex angle than the lower cone (32).
5. A holder (10) as claimed in claim 3 or 4, characterized in that
the apex angle of the upper cone (31) of each diabolo-shaped
projection (3) lies between 36 and 44.degree., and is preferably
approximately 40.degree., and in that the apex angle of the lower
cone (32) lies between 116 and 124.degree. and is preferably
approximately 120.degree..
6. A holder (10) as claimed in any one of the preceding claims,
characterized in that the first and the second projection (3A, 3B)
lie within two mutually adjoining quadrants of the main body, when
viewed in projection, and the third projection (3C) lies outside
said quadrants, when viewed in projection, and preferably at a
distance to the first and the second projection (3A, 3B) which is
as great as possible.
7. A holder (10) as claimed in any one of the preceding claims,
characterized in that the holder (10) comprises exactly three
projections (3) which are present approximately in the corner
points of an equilateral triangle.
8. A holder (10) as claimed in any one of the preceding claims,
characterized in that the third projection (3C) is provided with a
pin (9), in that the means (4) by which the third projection (3C)
is urged towards the first and the second projection (3A, 3B)
comprise a spring (4) fastened to the main body (2) and to the
third projection (3C), in that the first and the second projection
(3A, 3B) are each connected to the main body (2) by means of a
rivet joint, and in that all components (2, 3, 4) of the holder
(10) are made from stainless steel.
9. A method of manufacturing a semiconductor device whereby the
surface of a semiconductor substrate (1) is provided with a
conducting, semiconducting, or insulating region, or is divested of
such a region, and whereby the semiconductor substrate (1) is
fastened in a holder (10) for the purpose of providing or removing
said region, characterized in that the holder (10) is a holder (10)
as claimed in any one of the preceding claims.
10. A semiconductor device manufactured by a method as claimed in
claim 9.
Description
DESCRIPTION
[0001] The invention relates to a holder for a semiconductor
substrate, often referred to as substrate hereinafter for short,
comprising a main body which is provided with three or more
projections between which the substrate can be fixed in the holder
and of which at least a first and a second projection are fixedly
connected to the main body, while a third projection which is
present opposite the first and the second projection is movably
connected to the holder and can be moved in a direction away from
the first and the second projection, while the holder is provided
with means by which the third projection is urged towards the first
and the second projection. The invention also relates to a method
of manufacturing a semiconductor device in which such a holder is
used.
[0002] Such a holder, fitted with a substrate which is usually
round, is used for providing the surface of this substrate with a
(semi)conducting or insulating region or for removing such a
region. To achieve this, the holder is usually placed in a device
in which gases or liquids are present by means of which the above
operation can be carried out. The holder may also form part of said
device.
[0003] Such a holder is known from a US patent document published
under U.S. Pat. No. 4,971,676 on Nov. 20th, 1990. The holder shown
in FIG. 1 thereof comprises a main body in the form of a flat
carrier plate which is provided with four projections arranged in a
circle by means of which the substrate can be fixed in the holder.
Three of the projections each comprise a cylinder segment which
lies in a different quadrant of the carrier plate each time and
whose upper side is covered with a plate in the form of a circle
sector which extends over the substrate to be inserted and over the
carrier plate. A fourth projection is present in a fourth quadrant,
has the shape of a cylinder, and is capable of movement in a
direction away from the other projections and is urged towards the
fixed projections--and thus towards the substrate to be
inserted--by means of a spring. The fourth projection can be
recessed into the carrier plate, so that the substrate can be
passed over the carrier plate to below the other three
projections.
[0004] It is a disadvantage of the known holder that it covers part
of the substrate. As a result of this, the substrate is not exposed
in its entirety to the materials with which the surface of the
substrate is treated during a processing operation on the
substrate. Moreover, the known holder is comparatively expensive
owing to its complexity.
[0005] It is an object of the present invention to provide a holder
for a substrate which does not have the above disadvantage, which
renders it possible to process a portion of the substrate present
in the holder which is as large as possible, and which is at the
same time simple and inexpensive.
[0006] According to the invention, a holder of the kind mentioned
in the opening paragraph is for this purpose characterized in that
a lateral side of each projection facing towards the substrate to
be inserted is provided with a convex recess whose geometry is such
that exclusively the outermost edges of the both the upper surface
and the lower surface of the substrate to be inserted come into
contact therewith. The convex shape of the recess in the portion of
a projection facing the substrate achieves that a substrate can be
clamped in securely and fixedly in the holder. The entire surface
area--both the upper surface and the lower surface--of the
substrate is accessible to those substances with which a treatment
of the substrate is carried out thanks to a suitable choice of the
geometry of the convex recess, which is such that the substrate is
in contact with the recess only at the edges of both the upper
surface and the lower surface of the substrate. The portion of the
projection comprising the convex recess does cause some shadow
effect, but this is considerably less than in the known holder
thanks to the invention. A very suitable shape for the recess is,
for example, the shape of a triangle or a trapezium (=truncated
triangle). Preferably, the recess has a cross-section in radial
direction which is triangular. The advantages of this will be
explained further below. The shadow effect is still further reduced
by a suitable choice of the three-dimensional shape of the
projection, which will also be discussed further below.
[0007] In a preferred embodiment of a holder according to the
invention, the first and the second projection lie within two
mutually adjoining quadrants of the main body, when viewed in
projection, and the third projection lies outside said quadrants,
when viewed in projection, and preferably at a distance to the
first and the second projection which is as great as possible. A
holder suitable for, for example, round substrates, can accommodate
a spread in the diameters of these substrates as a result of this
placement of the projections. That is to say, substrates having a
diameter which is somewhat smaller or somewhat greater than the
nominal diameter can still be well retained in the holder. An
important advantage of the present invention is a spread in the
thickness of the substrates can also be accommodated in such a
placement, thanks to the convex recess and the manner in which this
makes contact with the substrate. Thus substrates having a
thickness greater or smaller than the nominal thickness can still
be satisfactorily clamped in in the holder. Preferably, the holder
comprises a total of exactly three projections which are present
approximately in the corner points of an equilateral triangle. Such
a holder is particularly suitable for round substrates.
[0008] In a very important and advantageous modification of a
holder according to the invention, the projections each have the
shape of a diabolo. This means that a substrate to be placed in the
holder makes contact with a projection in one point only at the
edge of its upper surface and in one point only at the edge of its
lower surface. The already comparatively small shadow effect of the
projections in a holder according to the invention is considerably
reduced thereby. This shape, where the recess has the shape of a
triangle or trapezium, also provides an excellent contribution to
the accommodation of fluctuations in thickness and diameter of the
substrate.
[0009] Preferably, the shape of the projections is that of a
diabolo which comprises two truncated cones placed on top of one
another. So this is a diabolo which does not have a cylindrical
central portion, unlike, for example, a yarn reel. The recess is
triangular in shape then. The advantage of such a diabolo shape may
be elucidated as follows. It is favorable to choose the apex angle
of at least the upper cone of the diabolo to be as small as
possible in order to achieve a minimum shadow effect. If the
diabolo has no cylindrical central portion in that case, it is
easier to achieve, also in the case of a thin substrate, that the
latter will make contact with the projection at the edges only. It
is favorable in practice to choose different values for the apex
angles of the two cones of the diabolo. The cone which is present
above the substrate and which causes the shadow effect mentioned
above is preferably given an apex angle which is as small as
possible, for example an apex angle of between 36 and 44.degree.,
and preferably approximately 40.degree.. A somewhat greater apex
angle is preferably chosen for the cone which lies below the
substrate. A substrate placed in the holder is moved more easily
into its end position as a result of this, which movement involves
a displacement over the slope formed by the lower cone. A suitable
apex angle for this lies between 116 and 124.degree. and is
preferably approximately 120.degree.. The height of the upper cone
31 is chosen to be as small as possible, again to reduce the shadow
effect.
[0010] An important additional advantage of a holder according to
the invention is that a substrate placed in the holder will always
lie parallel to the main body, provided the projections have the
same dimensions. This also contributes to the homogeneity of a
result of a treatment carried out on the substrate. A further
important advantage of the diabolo shape is that the projection
having this shape is not only easy to manufacture but is also
readily fastened on the main body of the holder. Finally, it is an
important advantage of a holder according to the invention that a
substrate can also be easily placed therein from above. The
comparatively complicated recessing of the movable projection into
the known holder may thus be omitted.
[0011] Preferably, the third projection is provided with a pin by
means of which this projection can be readily displaced in outward
direction with a hand or a finger. Furthermore, the means by which
the third projection is urged towards the first and the second
projection is preferably a spring fastened to the main body and to
the third projection. In a very favorable modification, the first
and the second projection are connected to the main body by means
of a rivet joint. All components of the holder are preferably
manufactured from stainless steel. The holder can thus be
manufactured in a simple and inexpensive manner. The holder is
highly suitable for many applications, in particular those in which
a layer is deposited on the substrate at an elevated
temperature.
[0012] The invention accordingly also relates to a method of
manufacturing a semiconductor device whereby the surface of a
substrate is provided with a conducting, semiconducting, or
insulating region, or is divested of such a region, and whereby the
substrate is fastened in a holder for the purpose of providing or
removing said region, characterized in that a holder according to
the invention is used for fastening the substrate. In a preferred
embodiment of a method according to the invention, the substances
by means of which the region is removed or provided are supplied
from the liquid phase or from the gas phase. The holder may be a
loose holder which is placed in a device in which the treatment of
the substrate is carried out. Alternatively, the holder may form
part of such a device. Semiconductor devices manufactured by such a
method have homogeneous properties irrespective of the question
from which portion of the substrate the semiconductor device is
formed.
[0013] The invention will now be explained in more detail with
reference to an embodiment and the accompanying drawing, in
which
[0014] FIG. 1 diagrammatically shows an embodiment of a holder for
a semiconductor substrate according to the invention, partly in
cross-section and partly in side elevation, and
[0015] FIG. 2 diagrammatically shows the holder of FIG. 1 in plan
view.
[0016] The Figures are not drawn true to scale, the dimensions in
the thickness direction being particularly exaggerated for greater
clarity. Corresponding regions have been given the same hatching
and the same reference numerals as much as possible.
[0017] FIG. 1 shows an embodiment of a holder for a semiconductor
substrate according to the invention diagrammatically, partly in
cross-section and partly in side elevation. A plan view of the
holder of FIG. 1 is shown in FIG. 2. The holder 10 in this example
comprises a main body 2, which here comprises a curved plate 2
which is only partly depicted in the Figure and which here forms
part of a vapor deposition device which is not shown in the
Figures. The plate 2 is provided with three or more, in this case
exactly three projections 3 by means of which a substrate 1 is held
fixed in the holder 10. At least a first and a second projection 3,
in this case exactly two projections 3A, 3B, are fixedly connected
to the plate 2. At least one, in this case exactly one, third
projection 3C is movably connected to the main body 2, lies
opposite the first and the second projection 3A, 3B, and is capable
of being moved away therefrom. The holder 10 is provided with means
4 by which the third projection 3C can be urged towards the first
and the second projection 3A, 3B.
[0018] According to the invention, a lateral side 5 of each
projection 3 facing towards the substrate 1 is provided with a
convex recess 6 whose geometry is such that exclusively the outer
edges of both the upper surface and the lower surface of the
substrate 1 come into contact therewith. This has the result on the
one hand that the substrate 1 can be securely fastened in the
holder 10, while on the other hand this fastening leaves the entire
upper surface (and lower surface) of the substrate 1 exposed. As a
result, the entire surface area of the substrate 1 is accessible to
substances by means of which a treatment of the substrate 1, in
this example the deposition of a layer of aluminum on the substrate
1, is carried out. A particularly suitable shape for the recess 6
is that of a triangle 6, preferably not truncated, as will become
apparent further below. Some shadow effect owing to the projections
3 is indeed still present, but it is considerably less than in the
known holder.
[0019] The projections 3 in the present example have the shape of a
diabolo 3. Thanks to this shape, the shadow effect of the
projections 3 mentioned above is further reduced. No more than a
single point lying on the upper edge and one on the lower edge of
the substrate 1 make contact with the recess 6 as a result of this
shape. The first and the second diabolo-shaped projections 3A, 3B
lie within two mutually adjoining quadrants, when viewed in
projection. The third diabolo-shaped projection 3C is present
outside said quadrants and occupies a symmetrical position with
respect to the first and the second projection 3A, 3B. In this
example, the three projections 3 lie approximately in the corner
points of an equilateral triangle.
[0020] The diabolo-shaped projections 3 here each comprise two
truncated cones 31, 32 placed on one another. The upper cone 31
here has a smaller apex angle than the lower cone 32. Thanks to the
steepness of the upper cone 31, the shadow effect of the
projections 3 mentioned above is practically nil, or at least very
substantially reduced. Thanks to the comparatively gentle slope of
the lower cone 32, the substrate 1, when placed in the holder, is
automatically driven into its final position by the pushing force
of the third projection 3C directed towards the two other
projections 3A, 3B. Said apex angles in this example are 40 and
120.degree., respectively, but they may be advantageously chosen to
lie between 36 and 44.degree. and between 116 and 124.degree.,
respectively. The projections 3 are in addition easy to manufacture
in this manner. It is also easy to fasten the projections 3 to the
plate 2, by means of rivet joints in this case. The plate 2 in this
example is for this purpose provided with openings 11 through which
respective hollow pins 12 are passed, which pins form part of the
projections 3. The rivet joint between a projection 3 and the plate
2 is created in that a conical rod 13 is driven with force into the
hollow pin 12. The openings 11 in the plate 2 issue into a
cylindrical recess 7, in which the lower cone 32 is accommodated,
at the upper side of the plate 2. This lower cone is accordingly
recessed into the plate 2 for a small portion. This further
facilitates the automatic displacement of the substrate 1 into its
final position as mentioned above.
[0021] A further advantage of the holder 10 in this example is that
the substrate 1 will arrive in a very well defined horizontal
position after its fastening in the holder 10. This also benefits
the homogeneity of the result of a treatment carried out on the
substrate 1. Important advantages, furthermore, are that minor
variations in both the diameter and the thickness of the substrate
1 do not adversely affect a satisfactory fastening in the holder
10. The dimensions of the holder 10 in this example are as follows.
The projections 3 are at a mutual distance of 9.5 cm, so that the
holder is suitable for accommodating a substrate 1 having a
diameter of 4". The nominal thickness of the substrate 1 is 0.3 mm.
The projections 3 have a height of 2.5 mm and the cones 31, 32 are
0.8 and 1.0 mm high, respectively, have a greatest diameter of 4
and 6.8 mm, respectively, and have a smallest diameter of 3.4 mm in
both cases. On top of the upper cone 31 of each fixed projection
3A, 3B there is a 0.6 mm high cylindrical portion, whereby a sharp
edge at the upper side of these projections 3A, 3B is avoided.
[0022] The third projection 3C in this embodiment is provided with
a pin 9 at its upper side, so that this projection 3C can be easily
moved away from the other ones with a hand or a finger. The plate 2
is provided with an opening 8 for this purpose. The means 4 by
which the third projection 3C is urged towards the first and the
second projection 3A, 3B here comprise a spring 4. The spring 4 is
connected to the plate 2 by means of a pin 14 and to the third
projection 3C. In the present example, all components of the holder
10, i.e. the plate 2, the projections 3, the spring 4, and the pin
14 are manufactured from stainless steel. Not only is the holder 10
inexpensive as a result of this, but it is also particularly
suitable for operations on the substrate which are carried out at
an elevated temperature.
[0023] The holder 10 of the present example is used in the
manufacture of a semiconductor device, when a conductive region is
provided on the surface of the semiconductor substrate 1 (which
comprises a pn junction), an aluminum layer in this case. To
provide the aluminum layer, the substrate 1 is placed in the
present embodiment of the holder 10. The aluminum layer provided
acts as a contact for diodes to be formed from the substrate and is
provided by means of vapor deposition at a temperature of
300.degree. C. The entire surface of the substrate 1 is evenly
coated thereby thanks to the holder 10 according to the invention.
This strongly benefits the yield and homogeneity of the
semiconductor devices manufactured, diodes in this case.
[0024] The invention is not limited to the embodiment described
since many modifications and variations are possible to those
skilled in the art within the scope of the invention. Thus the
dimensions of the holder and of the components thereof may be
differently chosen with a view to a different standard diameter of
the substrate. The holder may also be made from alternative
materials such as teflon, which renders the holder more suitable
for other treatments of the substrate than the vapor deposition of
a layer, such as chemical etching which often takes place at low
temperatures. Said treatments are not limited to those usual in the
manufacture of discrete components, indeed, the holder may be used
to advantage in the manufacture of ICs (=integrated circuits).
[0025] The carrier plate may also comprise several sets of
projections so that the holder can accommodate several substrates
at the same time. It is also possible to render the holder suitable
for treatments of both sides of the substrate placed therein and to
provide it, for example, with a mechanism for turning the holder
over through 180.degree., so that the upper side and lower side of
the substrate are interchanged. In that case, a symmetrical shape
of the projections in axial direction is more advantageous.
[0026] Compressed air may alternatively be used as a pressure means
for the movable projection. This is also true for the displacement
of this projection. This facilitates an automated remote control of
the holder.
[0027] The invention is not limited to holders having three
projections. It is possible to increase both the number of fixed
projections and the number of movable projections, as desired. The
additional projections should be suitably positioned, for example
on the circumference of a circle in the case of round substrates. A
specially adapted placement, however, is quite possible for
rectangular substrates such as those which are still occasionally
used, for example, for III-V semiconductor substrates.
* * * * *