Shooting Ions at Wafers: Will Ion Implantation Be the Next Upstream Solar Patent Battleground?


As noted in a previous post, solar patent litigation has begun to move upstream to encompass photovoltaic manufacturing equipment. 

Some recent public statements by PV production equipment maker Silicon Genesis (SiGen) about startup equipment vendor Twin Creeks Technologies (Twin Creeks) hint at more upstream solar patent trouble on the horizon. 

This Greentech Media story quotes a SiGen press release in which the company said it was “closely following” Twin Creeks announcements of a process “similar to [SiGen’s] beam-induced wafering…”  Additional SiGen statements and intimations included the following:

As the pioneers of beam-induced wafering and assuming it is not utilizing any of our technology embodied in our 100+ U.S. patent portfolio which we are monitoring…

The fact that Twin Creeks Technologies was founded by a venture capital firm shortly after it evaluated SiGen’s beam-induced wafering business plan and technology, including our prototype 2 million electron volt implanter is of concern.

According to Cleantech PatentEdgeâ„¢, SiGen owns at least 24 US, European, and international patents and applications, including U.S. Patent No. 7,687,786, entitled “Ion implanter for non-circular wafers” and 7,750,322, entitled “Ion implanter for photovoltaic cell fabrication” (Ion Implanter Patents).

The Ion Implanter Patents are directed to an ion implanter (100) comprising an ion source (120), a high-voltage extraction assembly (130), a dipole filter magnet (140), an accelerator (150), and an endstation (160).  The accelerator (150) applies an accelerating voltage between the dipole filter magnet (140) and the endstation (160).

This brings ions in the ion beam (145) to the implant energy necessary to shoot the ions into a silicon wafer before they reach the endstation (160).  The endstation (160) includes a disk (162) with pads (182) disposed around it.  The ion beam (145) irradiates silicon wafers disposed on the disk between inside circle (184) and outside circle (186), and the ions settle into the wafers at a finite depth. 

According to the same Greentech Media piece, the ions are then heated, and the result is a silicon wafer that cleaves off the substrate along the crystalline plane.

According to Cleantech PatentEdgeâ„¢, Twin Creeks owns 48 US, European, and international patents and applications, including two recently issued patents relating to ion implanters, U.S. Patent Nos. 7,989,784, entitled “Ion implantation apparatus and a method” and 8,044,374, entitled “Ion implantation apparatus” (Implantation Apparatus Patents).

The Implantation Apparatus Patents are directed to an ion implantation apparatus comprising a process chamber (10) having part spherical upper and lower walls (12, 13), a high-voltage enclosure (15), and an accelerator tube (18), which interconnects the the high voltage part of the vacuum chamber within the enclosure (15) and the process chamber (10). 

The process chamber (10) contains a process wheel (14).  Substrates for processing are carried in the process chamber (10) about the periphery of the wheel (14).

A beam of ions for implantation is produced in an ion source structure (16) within the high voltage enclosure (15) and directed into the magnet structure (17).  The magnet structure (17) bends the ion beam so that unwanted ions can be filtered from the continuing beam, which is directed towards the process chamber (10).

The acclerator tube (18) includes an electrically insulating element to allow the ion source and structures (16, 17) to be held at very high voltage and contains electrostatically biased electrodes to accelerate the ion beam to the required implant energy for delivery to the process chamber (10).

As mentioned above, solar cell manufacturing equipment has previously been the subject of patent litigation.  One lawsuit involved competitors Despatch Industries and TP Solar (TP) and their manufacturing equipment used for heat-treating silicon wafers for solar cells.  That case ended in a victory for TP.

Ion implantation may be the next upstream solar patent battleground.

Eric Lane Avatar

Eric Lane

Eric Lane, the founder and principal of Green Patent Law, is an intellectual property lawyer and registered U.S. patent attorney in New York and is a member of the bar in New York and California. Eric has more than two decades of experience working with wind, solar PV, CSP, biofuels, and geothermal, energy storage technologies, carbon capture and sequestration, medical devices, data communications, mechanical, chemical, internet and software.