Electrochemical assembly for forming semiconductor features

Abstract

Methods, apparatuses, and systems for forming deposited features on workpieces are provided herein. Generally, the techniques herein employ a deposition head to define an electrical field that facilitates electrochemical deposition. Other systems and controllers can be employed, which can assist in aligning or positioning the deposition head in proximity to a workpiece and controlling the size and location of the deposited feature.

1 . An assembly comprising:
 a deposition head comprising an array of anode pixels disposed on a proximal surface of the deposition head, wherein the array of anode pixels comprises a plurality of inert electrodes and a plurality of control devices configured to supply current to selected one or more of the plurality of inert electrodes;   a gap measurement system comprising one or more sensing elements, wherein the gap measurement system is configured to measure a distance between the proximal surface of the deposition head to a surface of a workpiece by measuring an impedance of a region between at least one sensing element of the one or more sensing elements and an underlying portion of the workpiece; and   a controller connected to the deposition head and configured to cause supplying a current and/or a voltage to the array or supplying a potential difference between the workpiece and the array, thereby forming an electric field defined by one or more of the anode pixels.   
     
     
         2 . The assembly of  claim 1 , further comprising an alignment system comprising:
 a plurality of fine actuator elements attached to the deposition head, wherein the fine actuator elements are configured to position the proximal surface of the deposition head within a first gap distance to the surface of the workpiece and/or to make the proximal surface of the deposition head to be on a plane that is parallel to the surface of the workpiece.   
     
     
         3 . The assembly of  claim 2 , wherein the alignment system is configured to control motion along five axes, including three mutually perpendicular linear axes, and two rotational axes oriented such that the deposition head planarity can be adjusted relative to the workpiece. 
     
     
         4 . The assembly of  claim 3 , wherein the alignment system is configured to control motion along the two rotational axes by a set of three fine actuator elements arranged in a triangle, or two fine actuator elements and a third fixed point arranged in a triangle. 
     
     
         5 . The assembly of  claim 1 , wherein at least one of the one or more sensing elements is disposed on the proximal surface of the deposition head and electrically connected to a circuit to determine a distance between the sensing element and the surface of the workpiece. 
     
     
         6 . The assembly of  claim 1 , wherein at least one of the one or more sensing elements is electrically coupled to a powering circuit and a sensing circuit. 
     
     
         7 . The assembly of  claim 6 , wherein the at least one sensing element comprises one of the plurality of inert electrodes. 
     
     
         8 . The assembly of  claim 1 , wherein the controller is configured to supply the current and/or the voltage or supply the potential difference in a manner that provides a deposited feature, and wherein the deposited feature is deposited by a single anode pixel or by a plurality of anode pixels. 
     
     
         9 . The assembly of  claim 8 , wherein the controller is configured to cause:
 supplying the current, the voltage, or the potential difference to a set of contiguous anode pixels to define a shape or a dimension of the deposited feature.   
     
     
         10 . The assembly of  claim 1 , further comprising a powering circuit electrically coupled to the plurality of inert electrodes, wherein the powering circuit is configured to apply a first electrical potential and/or current to have the inert electrodes serve as anodes relative to the workpiece and apply a second electrical potential and/or current to have the inert electrodes serve as cathodes relative to a secondary electrode. 
     
     
         11 . The assembly of  claim 10 , wherein the secondary electrode comprises a metal that electroplates onto the inert electrodes. 
     
     
         12 . The assembly of  claim 1 , wherein the gap measurement system is configured to measure the impedance of the region between the at least one sensing element and the underlying portion of the workpiece by applying an input signal wave to the at least one sensing elements. 
     
     
         13 . The assembly of  claim 12 , wherein the input signal wave has an amplitude of about 1 to 100 millivolts. 
     
     
         14 . The assembly of  claim 12 , wherein the input signal wave has a frequency of about 100 kHz to 10 Mhz. 
     
     
         15 . The assembly of  claim 12 , wherein the input signal wave has a frequency of about 1 MHz to 10 MHz. 
     
     
         16 . The assembly of  claim 1 , wherein the controller is further configured to use measured distances from the gap measurement system to maintain a distance between the proximal surface of the deposition head and a surface of a growing deposited feature on the workpiece. 
     
     
         17 . The assembly of  claim 16 , wherein the controller is further configured to maintain a constant distance between the proximal surface of the deposition head and the surface of the growing deposited feature on the workpiece. 
     
     
         18 . The assembly of  claim 16  the controller and/or the gap measurement system employs an empirical model relating impedance information to the distance between the proximal surface of the deposition head and the surface of the growing deposited feature on the workpiece. 
     
     
         19 . The assembly of  claim 1 , wherein the plurality of inert electrodes is recessed within holes in an insulating workpiece to thereby allow metal to be electroplated onto the plurality of inert electrodes from a secondary electrode and deplated from the plurality of inert electrodes onto a workpiece. 
     
     
         20 . The assembly of  claim 19 , wherein the holes in the insulating workpiece confine the location of the metal electroplated onto the plurality of inert electrodes. 
     
     
         21 . A method of electroplating a plurality laterally separated features onto a workpiece, the method comprising:
 (a) positioning a deposition head in a first position, and while in the first position, electroplating metal onto a plurality of inert electrodes of a plurality of anode pixels of the deposition head;   (b) before or after (a), measuring a gap between the deposition head and the workpiece or another substrate positioned at the location of the workpiece, wherein measuring the gap comprises determining an impedance of electrolyte proximate the gap; and   (c) positioning, by using the measured gap from (b), the deposition head in a second position proximate the workpiece, and while in the second position, electroplating metal from the plurality of inert electrodes onto the workpiece to, at least partially, form the laterally separated features.   
     
     
         22 . The method of  claim 21 , further comprising:
 (d) determining that the plurality laterally separated features have not been completely formed; and   (e) repeating operations (a), (b), and (c).   
     
     
         23 . The method of  claim 21 , further comprising after positioning a deposition head in the first position, and before electroplating metal onto the plurality of inert electrodes, delivering electrolyte between the deposition head and the workpiece. 
     
     
         24 . The method of  claim 21 , further comprising moving the deposition to a third position proximate the workpiece and electroplating an additional plurality of features onto the workpiece. 
     
     
         25 . The method of  claim 21 , further comprising etching a portion of a conductive seed layer on the workpiece. 
     
     
         26 . The method of  claim 21 , wherein measuring the gap between the workpiece and the deposition head comprises measuring gaps at three or more separated positions not in a line. 
     
     
         27 . The method of  claim 26 , wherein positioning the deposition head in a second position proximate the workpiece comprises modifying the position of the deposition head so that the workpiece and the deposition head are aligned on parallel planes. 
     
     
         28 . The method of  claim 21 , wherein positioning the deposition head in a second position proximate the workpiece comprises actuating one or more of a plurality of fine actuator elements attached to the deposition head to position a proximal surface of the deposition head within a first gap distance to the surface of the workpiece and/or to make the proximal surface of the deposition head to be on plane parallel to the surface of the workpiece. 
     
     
         29 . The method of  claim 21 , wherein positioning the deposition head in a second position proximate the workpiece comprises controlling motion along one or more of five axes, including three mutually perpendicular linear axes and two rotational axes.