Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
2000-01-19
2003-02-11
Nguyen, Nam (Department: 1741)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S229800, C204S297140
Reexamination Certificate
active
06517689
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an electroplating apparatus for depositing a plated film on a substrate such as semiconductor wafer, and in particular to a plating apparatus which is capable for producing a plated film of uniform thickness.
BACKGROUND ART
In recent years, electroplating methods have been adopted for filling the fine trenches and holes, fabricated on an object such as semiconductor wafer, with metallic plating such as copper to provide circuit interconnections. One such conventional plating apparatus is known as a facedown type plating apparatus.
FIG. 1
illustrates basic layout of this apparatus
10
comprised by: a plating vessel
101
; an object
12
to be plated whose surface to be plated is placed face-down in the upper region of the plating vessel
101
; a plating solution Q; a solution storage tank
103
; a circulation pump
104
for ejecting the plating solution Q from the bottom of the plating vessel
101
through a plating solution supply pipe
105
at right angles towards the plating surface of the substrate
12
.
Plating solution Q overflowing from the plating vessel
101
is collected in the solution recovery trough
106
. A specific voltage is applied between the anode
107
and the plating jig
11
fastening the substrate
12
to serve as the cathode, so that the plating current flows between the anode
107
and the substrate
12
to form a plated film on the plating surface.
FIG. 2
is a cross sectional view of a portion of the feeding section of the plating jig
11
.
As shown in this diagram, the plating jig
11
fastening the substrate
12
such as semiconductor wafer is placed opposite to the anode
107
in the plating vessel
10
containing the plating solution Q. A direct current voltage is applied between the plating jig
11
and the anode
13
by the plating power supply
14
for flowing plating current to form a plated film on the substrate
12
.
Plating jig
11
has a feeding section which has feeding contacts
15
to contact the conductive part of the plating surface of the substrate
12
, and when the contact points and the plating power supply are electrically connected, plating current flows from the plating power supply via the anode, the substrate and the contact points.
As shown in the diagram, the plating feeding section is comprised of a ring frame
17
which has a ring packing
18
on the inner periphery thereof and a feeding ring
19
which has a series of feeding contacts (or contact points)
15
spaced at a given distance along the periphery of the ring
19
. The ring
19
and contacts
15
are located at the inside of the ring packing
18
. The tip of the feeding contact
15
touches outer periphery of the substrate
12
where a conductive layer(not shown) is formed thereon. Then electrical contact between the conductive layer to be plated and the feeding contact
15
is formed. The tip of the packing
18
is pressed against the surface of the substrate
12
to form a tight seal so as to prevent the plating solution from entering into the inside of the packing
18
. Therefore, the feeding contact
15
and the feeding ring
19
are prevented from being exposed to the plating solution.
FIGS. 3 and 4
show the conventional arrangement of feeding contact
15
attached on the feeding ring
19
, respectively. In
FIG. 3
, feeding contacts
15
are provided at certain spacing on the feeding ring
19
. While in
FIG. 4
, the feeding ring
19
is divided by insulators
20
into a plurality of electrically isolated sections (four sections in the example) and the feeding contacts
15
are attached to each of the divided sections of the feeding ring
19
.
As shown in
FIG. 3
, according to the arrangement of a plurality of feeding contacts
15
attached on a common feeding ring
19
, contact resistance of each feeding contact
15
varies from point to point, such that some of the feeding contacts
15
can pass current readily while others can not pass current easily. It cause a problem that plating thickness tends to be thinner at places nearby where those feeding contacts
15
can pass less current than other feeding contacts.
Also, as shown in
FIG. 4
, according to the arrangement of the feeding section
19
which is divided into a plurality of feeding sections separated by insulators
20
with feeding contacts
15
respectively, current in each feeding contact
15
can be controlled so that the differences of currents among the feeding contacts
15
can be minimized. However, the plating current is difficult to flow at the place between the feeding contacts
15
through the plating solution, resulting a problem that thinner plating thickness tends to be obtained in such regions of the plating surface.
DISCLOSURE OF INVENTION
The present invention is provided to solve the problems outlined above, so that an object of the present invention is to provide a plating apparatus having conduction detection means to enable detection of contact states (contact conditions) of the plurality of feeding contacts touching the substrate through the conduction detection sections so as to control the uniformity of the plating current flowing through the feeding contacts, and thereby obtaining uniform plating thickness on the substrate.
To achieve this object, there is provided an electroplating apparatus having a plating vessel for positioning an electrode in opposition to a substrate electrically affixed to a plating jig through a plurality of feeding contacts for impressing a specific voltage between the electrode and conductive layers provided on a plating surface of the substrate, thereby flowing a plating current from the electrode to the substrate through the feeding contacts so as to deposit a plated film on the substrate, wherein a feature is that a conduction detection device is provided to detect electrical conductivity properties between individual feeding contacts of the plating jig and the conductive layers on the substrate.
Also, it is preferable that the conduction detection device be provided with a plating current detection device to detect flow of electrical current through individual feeding contacts, so as to determine electrical conductivity of individual feeding contacts according to respective values of current flow detected by the plating current detection device.
Further, it is preferable that the conduction detection device be provided with a contact resistance measuring device to measure contact resistance between a conductive layer on the plating surface of the substrate and individual feeding contacts so as to determine electrical conductivity properties of respective feeding contacts according to respective values of contact resistance measured by the contact resistance measuring device.
Accordingly, because a conduction detection device is provided to determine electrical conductivity properties of each contact point of the plurality of feeding contacts, it is possible to confirm the state of conduction of plating current through each feeding contact, thereby eliminating one reason for producing non-uniform thickness of plated film.
Also, because the apparatus is provided with a plating current detection device and a plating current control device so that current flow through individual feeding contacts can be adjusted individually, it is possible to deposit a plated film of a uniform thickness on the plating surface of the substrate.
Also, in the electroplating apparatus of the present invention, each feeding contact may be made in a form of teeth contact to touch the conductive layer on the plating surface. Such a shape of the feeding contact enables to produce relatively uniform contact pressures on the conductive layers so as to generate uniform conduction states of electrical contacts, thereby enabling to deposit a uniform thickness of plated film in the vicinity of individual feeding contacts. Also, by adjusting the current flowing between the various contact points suitably, it is possible to obtain a uniform thickness of plated film over the entire plating surface of the substrate.
REFEREN
Chono Atsushi
Hongo Akihisa
Mishima Koji
Ogata Akira
Sendai Satoshi
Ebara Corporation
Nguyen Nam
Nicolas Wesley A.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Plating device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Plating device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plating device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3140783