Device and method for monitoring an electrolytic process
In manufacturing integrated circuits voids in the metal layer may readily form during electrolytic metal deposition. In order to avoid these faults which adversely affect the functionality of the circuits, the invention suggests to utilize for metal deposition an electrolysis device comprised of at least one anode and at least one cathode and in which at least one reference electrode is disposed at the surface of the at least one anode or at the surface of the at least one cathode. A voltmeter is respectively provided for detecting the electric voltages between the at least one anode and the at least one reference electrode and between the at least one reference electrode and the at least one cathode.
1 . A device for monitoring an electrolytic process, comprising at least one anode and at least one cathode, at least one reference electrode being disposed at the surface of the at least one anode or at the surface of the at least one cathode, at least one voltmeter being respectively provided for detecting the electric voltages between the at least one anode and the at least one reference electrode and between the at least one reference electrode and the at least one cathode.
2 . The device according to claim 1 , wherein at least one first reference electrode is disposed at the surface of the at least one anode and at least one second reference electrode is disposed at the surface of the at least one cathode and wherein a voltmeter is respectively provided for detecting the electric voltages between the at least one anode and the at least one first reference electrode, between the at least one first and the at least one second reference electrode and between the at least one second reference electrode and the at least one cathode.
3 . The device according to one of the aforementioned claims 1 - 2 , wherein the at least one reference electrode communicates through capillaries with the surface of the at least one anode or with the surface of the at least one cathode.
4 . The device according to claim 3 , wherein means are provided by means of which electrolyte fluid is deliverable through the capillaries to the at least one reference electrode.
5 . The device according to one of the aforementioned claims 1 - 2 , wherein the at least one anode and the at least one cathode are paralleled and oriented horizontally or tilted from horizontal.
6 . The device according to one of the aforementioned claims 1 - 2 , wherein the cathode is a wafer or a chip carrier substrate and the anode is a metal plate.
7 . A method of monitoring an electrolytic process in an electrolytic cell comprised of at least one anode and of at least one cathode, at least one reference electrode being disposed at the surface of the at least one anode or at the surface of the at least one cathode, at least one voltmeter being respectively provided for detecting the electric voltages between the at least one anode and the at least one reference electrode and between the at least one reference electrode and the at least one cathode,
said method involving the following method steps:
a) providing an electric current flow between the at least one anode and the at least one cathode,
b) concurrently detecting the respective electric voltages between the at least one anode and the at least one reference electrode and between the at least one reference electrode and the at least one cathode.
8 . The method of claim 7 , wherein at least one first reference electrode, which is disposed at the surface of the at least one anode and at least one second reference electrode, which is disposed at the surface of the at least one cathode are provided,
method step b) including the following partial method steps:
b1) detecting the electric voltage between the at least one anode and the at least one first reference electrode,
b2) detecting the electric voltage between the at least one first reference electrode and the at least one second reference electrode and
b3) detecting the electric voltage between the at least one second reference electrode and the at least one cathode.
9 . The method according to one of the claims 7 and 8 , wherein the at least one reference electrode is brought into contact with the surface of the at least one anode or with the surface of the at least one cathode by way of capillaries.
10 . The method according to claim 9 , wherein electrolyte fluid is delivered through the capillaries to the at least one reference electrode.
11 . The method according to one of the claims 7 - 8 , wherein the at least one anode and the at least one cathode are paralleled and oriented horizontally or tilted from horizontal.
12 . The method according to one of the claims 7 - 8 , wherein the cathode is a wafer or a chip carrier substrate and wherein the anode is a metal plate and wherein the metal is electrolytically deposited on the wafer.