Varian Semiconductor Equipment Associates, Inc.

Varian Semiconductor Associates, Inc.

Atul Gupta

Joseph C Olson

Nicholas P T Bateman

Benjamin B Riordon

Russell J Low

Nicholas Pt Bateman

Timothy J Miller

Vikram Singh

William Tyler Weaver

Anthony Renau

Deepak Arabagatte Ramappa

Kevin M Daniels

Steven M Anella

Ludovic Godet

Paul J Murphy

Paul Sullivan

James Paul Buonodono

Edmund Jacques Winder

Kenneth Harry Purser

Christopher R Hatem

Robert J Mitchell

Jonathan Gerald England

Ziwei Fang

Donna Smatlak

Harold M Persing

Gregg Alexander Norris

San Yu

Benjamin D Riordon

A plasma processing apparatus comprises a plasma source configured to produce a plasma in a plasma chamber, such that the plasma contains ions for implantation into a workpiece. The apparatus also includes a focusing plate arrangement having an aperture arrangement configured to modify a shape of a plasma sheath of the plasma proximate the focusing plate such that ions exiting an aperture of the aperture arrangement define focused ions. The apparatus further includes a processing chamber containing a workpiece spaced from the focusing plate such that a stationary implant region of the focused ions at the workpiece is substantially narrower that the aperture. The apparatus is configured to create a plurality of patterned areas in the workpiece by scanning the workpiece during ion implantation.

Apparatus and method for controllably implanting workpieces

An improved method of tilting a mask to perform a pattern implant of a substrate is disclosed. The mask has a plurality of apertures, and is placed between the ion source and the substrate. The mask and substrate are tilted at a first angle relative to the incoming ion beam. After the substrate is exposed to the ion beam, the mask and substrate are tilted at a second angle relative to the ion beam and a subsequent implant step is performed. Through the selection of the aperture size and shape, the cross-section of the mask, the distance between the mask and the substrate and the number of implant steps, a variety of implant patterns may be created. In some embodiments, the implant pattern includes heavily doped horizontal stripes with lighter doped regions between the stripes. In some embodiments, the implant pattern includes a grid of heavily doped regions.

Angled multi-step masking for patterned implantation

An improved method of doping a substrate is disclosed. The method is particularly beneficial to the creation of interdigitated back contact (IBC) solar cells. A paste having a dopant of a first conductivity is applied to the surface of the substrate. This paste serves as a mask for a subsequent ion implantation step, allowing ions of a dopant having an opposite conductivity to be introduced to the portions of the substrate which are exposed. After the ions are implanted, the mask can be removed and the dopants may be activated. Methods of using an aluminum-based and phosphorus-based paste are disclosed.

Self-aligned ion implantation for IBC solar cells

An improved technique for processing a substrate is disclosed. In one particular exemplary embodiment, the technique may be realized as a method for processing a substrate. The method may comprise ion implanting a substrate disposed downstream of the ion source with ions generated in an ion source; and disposing a first portion of a mask in front of the substrate to expose the first portion of the mask to the ions, the mask being supported by the first and second mask holders, the mask further comprising a second portion wound in the first mask holder.

Technique for processing a substrate

An improved bifacial solar cell is disclosed. In some embodiments, the front side includes an n-type field surface field, while the back side includes a p-type emitter. In other embodiments, the p-type emitter is on the front side. To maximize the diffusion of majority carriers and lower the series resistance between the contact and the substrate, the regions beneath the metal contacts are more heavily doped. Thus, regions of higher dopant concentration are created in at least one of the FSF or the emitter. These regions are created through the use of selective implants, which can be performed on one or two sides of the bifacial solar cell to improve efficiency.

Bifacial solar cell using ion implantation

A method of LED manufacturing is disclosed. A coating is applied to a mesa. This coating may have different thicknesses on the sidewalls of the mesa compared to the top of the mesa. Ion implantation into the mesa will form implanted regions in the sidewalls in one embodiment. These implanted regions may be used for LED isolation or passivation.

LED mesa sidewall isolation by ion implantation

A first facet of each of a plurality of pyramids on a surface of a workpiece is doped to a first dose while a second facet and a third facet of each of the plurality of pyramids is simultaneously doped to a second dose different than the first dose. The first facets may enable low resistance contacts and the second and third facets may enable higher current generation and an improved blue response. Ion implantation may be used to perform the doping.

Manufacturing high efficiency solar cell with directional doping

Glitches during ion implantation of a workpiece, such as a solar cell, can be compensated for. In one instance, a workpiece is implanted during a first pass at a first speed. This first pass results in a region of uneven dose in the workpiece. The workpiece is then implanted during a second pass at a second speed. This second speed is different from the first speed. The second speed may correspond to the entire workpiece or just the region of uneven dose in the workpiece.

Handling beam glitches during ion implantation of workpieces

An improved method of producing solar cells utilizes a mask which is fixed relative to an ion beam in an ion implanter. The ion beam is directed through a plurality of apertures in the mask toward a substrate. The substrate is moved at different speeds such that the substrate is exposed to an ion dose rate when the substrate is moved at a first scan rate and to a second ion dose rate when the substrate is moved at a second scan rate. By modifying the scan rate, various dose rates may be implanted on the substrate at corresponding substrate locations. This allows ion implantation to be used to provide precise doping profiles advantageous for manufacturing solar cells.

Masked ion implant with fast-slow scan

A method of tailoring the dopant profile of a substrate by utilizing two different dopants, each having a different diffusivity is disclosed. The substrate may be, for example, a solar cell. By introducing two different dopants, such as by ion implantation, furnace diffusion, or paste, it is possible to create the desired dopant profile. In addition, the dopants may be introduced simultaneously, partially simultaneously, or sequentially. Dopant pairs preferably consist of one lighter species and one heavier species, where the lighter species has a greater diffusivity. For example, dopant pairs such as boron and gallium, boron and indium, phosphorus and arsenic, and phosphorus and antimony, can be utilized.

Use of dopants with different diffusivities for solar cell manufacture

An improved method of implanting a solar cell is disclosed. A substrate is coated with a soft mask material. A shadow mask is used to perform a pattern ion implant and to set the soft mask material. After the soft mask material is set, the mask is removed and a blanket implant is performed.

Use of a shadow mask and a soft mask for aligned implants in solar cells

An improved, lower cost method of processing substrates, such as to create solar cells is disclosed. In addition, a modified substrate carrier is disclosed. The carriers typically used to carry the substrates are modified so as to serve as shadow masks for a patterned implant. In some embodiments, various patterns can be created using the carriers such that different process steps can be performed on the substrate by changing the carrier or the position with the carrier. In addition, since the alignment of the substrate to the carrier is critical, the carrier may contain alignment features to insure that the substrate is positioned properly on the carrier. In some embodiments, gravity is used to hold the substrate on the carrier, and therefore, the ions are directed so that the ion beam travels upward toward the bottom side of the carrier.

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Beverly, MA, United States of America

Atul Gupta