F u l l y i n t e g r a t e d c e l l p r o d u c t i o n f o r h i g h e s t c a p a c i t i e s

C E L L P R O D U C T I O N

The Concept: 100 % by SCHMID

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A Schmid Turnkey System offers state-of-the-art technology with

highest investment security. The concept is based on a fully automa-

ted and interlinked horizontally operated production ensuring highest

efficiency and yield for future market demands.

100 % of all process- and automation tools are produced within

the Schmid group eliminating any interface- and inter linkage

discussions

Schmid‘s own Technology Centers for wafer, cell and module are

assuring the access to the next generation technology. Synergy

effects to wafer and module developments are permanently

evaluated and integrated into new developments

Worldwide networked process, project and service support is

guaranteeing the right support wherever required

Green production can be assured by processes with minimized

energy-, water- and chemical consumption

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SCHMID Turnkey Competence

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For the realization of turnkey solutions, Schmid provides its customers extensive service

packages. These services assure a short realization time of complex assembly concepts and

enable a fast changeover to full production.

Consultancy concerning technical questions, settlement and profitability calculations by

experienced expert teams

Production facility planning (requirement profiles for buildings as well as utility supply

and disposal)

Mechanical engineering, installation on-site as well as integration of the process technology

Customer specific training programs performed in Schmid‘s own training and technology

centers as well as commissioning of the production lines

Overall process optimization by Schmid – experienced process specialists assure an efficient

and fast production ramp-up

Integration of customers in the Schmid‘s own research and development program to enable

lasting advancements in efficiency and profitability

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Decision SupportTechnologyLocationCoO

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Equipment Installation

Training andRamp up

Process Optimization

R+D Cooperation

CustomerUtility + Facility

Planning

Higher Efficiency – Higher Yield!

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... due to smart production concepts

We cover the complete value chain in mono- and multi-crystalline solar cell production with a high level of vertical

integration. Schmid is your partner for innovative single processes, automated production equipment and complete

turnkey solutions. As global technology market leader, we work continuously in our Schmid technology centers at

optimizing our systems technology and at further development of process concepts in cell production. Our customers

receive their turnkey production lines together with a fully comprehensive process warranty guaranteeing achievement

of the performance parameters of efficiency, exploitation and throughput.

Research and Development

TCS Freudenstadt

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Where solutions are found to meet future demands

As a technology-orientated company we carry out our research and development work at our

own product-related technology centres (TCS). Equipped with state-of the-art technology, the

centers offer ideal laboratory conditions for scientific tests, application-based developments and

future-orientated research projects. The TCS not only serves as the headquarters for our research

work, but also provides the ideal environment for carrying out customer R&D. Here we demons-

trate that our process technologies possess the required characteristics under real production

conditions and show the latest product developments to visitors live. In the sector of basic science

we work closely together with leading research institutes. Joint projects between Schmid and the

PV department of the faculty of physics at the University of Constance at the “Schmid Photovoltaic

Innovation Center of Expertise“ (SPICE) to push the limits of all processes in the PV value chain.

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Worldwide Competence

Schmid Production Wet Processes

Gebr. Schmid GmbH & Co. (GSF) | Freudenstadt | Germany

Facility Co. Ltd. (FAC) | Sagamihara-city | Japan

Schmid Vacuum Technology GmbH (SVT) | Karlstein | Germany

Schmid Zhuhai Ltd. (SZL) | Zhuhai | China

Schmid Production Automation and further Processes

Schmid Technology Systems GmbH (STN) | Niedereschach | Germany

Schmid Technology GmbH (STS) | Schwetzingen | Germany

Schmid Automation Asia Ltd. (SAA) | Chung Li City | Taiwan

Schmid Automation China Ltd. (SAC) | Dongguan | China

Schmid Production Furnaces and Measuring

SierraTherm Inc. (STI) | Watsonville | USA

Schmid YAYA Technology Co. Ltd. (SYT) | Hsinchu City | Taiwan

Production in a global networkProducing certain product lines at various locations gives us a high level of production

reliability and enables us to react to market demands quickly and flexibly. Depending on

the individual situation, capacities are redistributed, expanded and synergies utilized.

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SCHMID Group

Schmid Research and Development –

Technology Center

TCS Freudenstadt | Germany

STC Dunningen | Germany

TCS Zhuhai | China

Legend Production Wet Processes Production Automation and further Processes Production Furnaces and Measuring Sales and Service Technology Center Schmid

SCHMID Turnkey Process

Inline ConceptClassic, horizontal inline production with fully automated

handling and integrated transport and buffer system achieving

capacities of 30 to 100 MW annually in individual turnkey lines.

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Rapid start-up of process line

High productivity levels of up to 3,300 cells

per hour per square meter of process machinery

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Horizontal inline process without process cassettes

Fully automated wafer handling

Integrated quality management and data storage system

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Efficiency Measuring

+ Classification

Touchless Metallization incl. Ag-LIP

Antireflection Coating

Selective Emitter Edge

+ PSG Removal

Phosphorus Doping

+ Diffusion

Saw Damage Etching

+ Alkaline or Acid Texturing

Wafer InspectionChemical Edge

Isolation

Cell Sorter

Load Cell LineAcid/Alkaline TexturingPhosphorus Doper

Diffusion FurnaceBuffer +Conveyor

Ink Jet (Selektive Emitter)

Single-Side Edge Isolation+ PSG Etching

+ Selective Emitter Etch and Strip

Converter

PECVD

PECVDLoader/ Unloader

Pick + PlaceRobot

Metallization Process Firing Light Induced Plating

SCHMID Turnkey Concepts

Cluster Concept

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The space-saving horizontal cluster process line with low automation requirements for annual

capacities of 30 MW to over 1 GW offers the highest possible productivity enabled by process

machines with a production capacity of up to 7,000 cells/h each.

Simple capacity and process expansion during ongoing production

Space-saving system layout and no interfacing required between processes

Integration of individual process clusters in existing cell concepts possible

Interlinkage of all process steps by means of the intelligent Montrac intralogistics system

or by transport trolleys

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Customized Turnkey Solutions

Our customer-specific, horizontal configuration of the processing line assures individual

solutions for high-quality cell production.

• Bespoke production lines operating with standardized process components

• Customer processes can be optimized in our own technology centers

• Competent consulting management

• Integration of customer-specific process steps in the Schmid turnkey concept

Cell Sorter Light Induced Plating

Firing

Metallization Process

Laser Transfer Printer

Alkaline Texturing

DryingPECVD

POCI3 DoD Inkjet Selective Emitter Masking Single-Side Edge Isolation+ PSG Etching

+ Selective Emitter Etch and Strip

Acid and Alkaline Texturing

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The inline texturing processes remove saw

damage and enlarge the surface of either

mulit-crystalline or mono-crystalline wafers.

The Acid Texturing Process is mainly

applied on multi-crystalline wafers to create

isotropic surface texture for reducing the sun

ray reflection on the subsequent cell surface.

Only on mono-crystalline wafers the Alkaline

Texturing Process is applied to create the

pyramidal even surface texture which reduces

reflection on the subsequent cell surface.

High process repeatability and reliability

No additional wafer handling required

Reduced chemistry consumption

Automatic wafer tracking and process

monitoring

Stain-free drying

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Alkaline textured wafer surface

Acid textured wafer surface

Process Technologies

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Phosphorus Doping and Diffusion

The POCl3 diffusion furnace is a batch version to form the p-n junction. The long diffusion

time and a controlled atmosphere guarantee a very homogeneous p-n junction with minimal

“dead layer thickness”. The POCl3 liquid source is stored in a temperature controlled cryostat.

The loading system is optionally equipped with a horizontal laminar flow to provide a class

10- compatible polished stainless steel scavenger.

The inline Phosphorus Doper creates a very homogeneous mist by ultrasonic transducers.

A controlled exhaust system is provided for a defined vapour flow. The wafers, which are

laying on a continuous moving belt, are transported through the chamber. During this

process the mist is deposited on the wafer. The p-n junction is formed in the following diffusion

furnace which is provided with several strictly controlled and metal-free heating zones.

Acid textured wafer surface

Single Side Edge Isolation and PSG Removal

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The potential on the front and rear sides of the wafers is isolated by etching an isolation edge on one

side of the wafer. This Edge isolation is achieved in a horizontal, fully automatic, wet processing

system utilizing a three step process: HF/HNO3, KOH, and HF. DI water-cascade rinses are applied

after every chemical process step to minimize drag-in and drag-out. The multiple cascade technology

decreases the consumption of DI water. In phosphor glass etching, phosphor glass removal is

accomplished with HF. Auto-dosing of the HF chemistry is done via conductivity control. The inno-

vative system assures up to 80 % lower chemical consumption compared to conventional methods.

In the final drying operation, the side channel blowers of the Dry Jet System lower the noise level

and reducing operating costs over conventional drying systems. The efficiency of the Dry Jet is en-

hanced by the long operating zone, producing uniform and stain-free dried wafers. The safety interlock

controls can be integrated into the facility management system. In emergency cases all mediums

can be interrupted and drain systems automatically triggered, based on the programmed reactions.

Process Technologies

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PECVD

In the PECVD (Plasma Enhanced Chemical Vapour Deposition) coating system the wafers are

coated with an antireflection layer consisting of silicon nitride. This technology uses a direct plasma

reactor which achieves improved cell efficiency and higher density of Si-nitrate layer in comparison

to the remote plasma reactor. The PECVD system ensures an excellent surface passivation due to

high process temperatures and the direct plasma process and guarantees a stable and reproducible

process and is characterized by outstanding layer uniformity.

In the PECVD Loader / Unloader the PECVD-processed wafers in the tray are exchanged for

unprocessed wafers in a one step process. By dint of a system consisting of eight Bernoulli grip-

pers the processed wafers are removed from the tray, inspected for breakage and placed on two

outfeed conveyors. At the same time two infeed conveyors supply unprocessed wafers to the transfer

position, here they are placed by the gripper system into the vacant tray positions. This process is

repeated until the tray is completely refilled with unprocessed wafers.

Metallization

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The modular concept of the Screen Printer with three printing

stations plus buffering ensures a highly efficient process with high

alignment accuracy, high throughput and the capability of handling

thin wafers. The metal pastes on the front and the rear sides of the

cells are subsequently dried and fired by an inline, conveyorized belt

furnace.

Contrary to screen-printing technology, with laser transfer printing the

metallization is carried out contact-free. Due to trouble-free printing

of smallest lines (min. 80 µm @ 600 dpi) the shading is minimized.

The metalliferous pastes are printed in various patterns in-line and

entirely in digital format. The LTP 1500 is suitable for coating both

the front and rear sides of all solar cell types.

The Laser Transfer Printer (LTP) is required in combination

with process expansion Light Induced Plating for contact-free

metallization of the solar cells.

Process Technologies

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Inspection, Testing and Sorting

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The Load Cell Line ensures the feeding of intact

and first-class wafers into the cell production line.

Therefore the wafers are inspected for damages by

means of different measuring systems (inspection

for µ-cracks / geometry and surface measuring).

According to special demands on automation

level and complexity of inspection different types

of the Load Cell Line are available.

Process Technologies

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The Cell Sorter is a highly efficient system on a

small footprint of 16.8 m², which measures and

sorts thin cells with thicknesses down to 160 µm.

In the measuring unit two measuring stations per

cell are approached (sun simulation and front

side inspection with Blue Eye, optional rear side

inspection). According to the measuring results

the sorting into corresponding classification is

accomplished in the sorting unit. The classification

parameters are fully configurable.

Available types: Cell Sorter 3000 (3000 cells per

hour / 24 sorting boxes) and the Cell Sorter 5000

(5000 cells per hour / 48 sorting boxes).

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SE – Selective Emitter

Selective Emitter Process

The inline system for producing selective emitters with the aid of inkjet printing technologies

is integrated into the Single Side Edge Isolation and PSG equipment.

Basic concept of the Selective Emitter

With this combined printing and etching technology, the high phosphorous doping layer is

selectively etched on to the cell and only maintained in those places where contacts are subse-

quently printed. For this purpose a wax mask is applied in inkjet printing. The utilisation concept

of the selective emitter increases the efficiency of the solar cell by up to 0.8 %.

Reduction of the doping concentration for the active emitter area

Higher doping concentration underneath the fingers and bus bars compared to the

optical active cell area

The DoD Inkjet Printer is required in combination with the SE-process for digital printing

of the etch masks.

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Process Upgrades

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SE – Selective Emitter

Physical effects

Reduction of surface recombination (Sfront)

Reduction of Auger-Recombination (J0E)

Reduction of Band Gap Narrowing (J0E)

Quantum efficiency improvement by reduction

of the dead layer

®Improved „Blue response“ of the cell ® Gain In Isc®Reduction of Sfront, (J0E) and BGN ® Gain In Voc

Higher sheet resistivity underneath fingers and busbars

Thicker emitter layer

®Lower metallization contact resistivitypc

®Larger process window during firing

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Process Upgrades

HiMeT – High Efficiency Metallization Technology

Magnification = 100 X | High voltage = 12.00 kV | Signal A = SE 1 | Operating distance = 14 mm A = Plated grid line | B = Seed layer

The currently developed fine line metallization uses Ag-nano-

particles and Ag-LIP. The Ag-nano-particles are coated with

a glass frit and pass through the standard co-firing process.

Narrowing of alignment tolerances for selective emitter

(gain: VOC, JSC)

Improvement of electrode contact resistance and wide

firing process window (VOC, FF)

Reduced mechanical stress compared to screen printing

due to touchless printing

Throughput of 1650 wafers per hour

Highly accurate positioning

Reduction of silver consumption

Ag-nano-particle as seed layer line for contact information

(width of 35 µm)

Ag-LIP to generate electrode conductivity (width 60 – 65 µm)

Potential: 0.4 – 0.6 % efficiency gain

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LIP – Light Induced Plating

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Using Light Induced Plating Technology very fine-structured and low-shadowing contact

grids can be produced on the solar cell. In the first step the front contact fingers, so-called seed

layers, are applied, for example using inkjet printing technology. In the second step, the contact

lines are silver-plated to improve their electrical conductivity. The illuminated solar cell supplies

the required electricity for this purpose by increasing front side electrode voltage.

LED light sources, adjustable light

Higher conductivity

Efficiency up to +0,3 %

Healing process: closing interrupted printing-structures

Can be used for the deposition of different metals

Less grid shadowing due to thinner contact lines

Stable and uniform local voltage distribution within the solar cell

High output rate due to contact-free metallisation and smooth transport

High process stability guarantees high reproduction accuracy

Process control achieved by comprehensive process monitoring and visualisation

Stable processing due to continuous replenishment of the process fluids

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Process Upgrades

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Buffering, Transport and Handling

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The Conveyor is available in various lengths between 500 mm and 2000 mm and transports the

wafers/cells on two, four or five lanes within the production line. As they are fed into the machine,

the wafers/cells are aligned and registered by sensors for wafer/cell tracking. The individual control

of each conveyor belt allows deceleration or acceleration of the wafers/cells on their individual

track in order to synchronize the transfer to the following machine.

The wafers/cells are guided into the Flip Station on five tracks and are aligned by means of

centering rails. Infeed sensors ensure that the wafers/cells are correctly positioned when entering

the station. In the first step, a turning wheel with six slits picks up the first row of wafers/cells and

turns them by 60° until the next row can be picked up. After the third step and a rotation of 180°,

the wafers/cells leave the station via the exiting track.

The Pick+Place Robot is an effective and flexible high speed solution for different scopes requiring

highest handling accuracy. The number of traces at the conveyors can vary from one to five.

Furthermore the wafers/cells can be removed from or be placed into boxes. Integrated camera

systems detect position, defects and overlapping wafers/cells. Bernoulli grippers assure gentle and

non-contact handling.

Inline Automation Equipment

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The Buffers provide as intermediate storage of

wafers/cells with variable capacities. Thereby the

system assures that interruptions do not impact

continuous process operation. All buffers are coor-

dinated by a central control unit for a completely

automatic operation. Normally wafers/cells are

transferred through the buffers without interruption.

During disturbances the buffering occurs accor-

ding to the FILO-principle. Several independently

speed controlled conveyors in the Flex Buffer are

able to create gaps. In doing this fully buffered

magazines can be emptied during regular ope-

ration resulting in an increasing throughput.

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Multi Lane Loading and Unloading

Multi Lane Loader and Multi Lane Unloader provide for a continual loading respectively

unloading of process equipment. Thereby the wafers/cells are transported on five lanes. In

the loader the wafers/cells are manually fed in two drawers with five boxes each and carefully

separated by means of a lateral nozzle bar. The wafers/cells are subsequently removed from

the active drawer via a Bernoulli gripper system with five grippers and places onto the outlet

conveyor belts. In reverse a quintuplicate Bernoulli-gripper system in the Unloader removes the

wafers/cells from the infeed conveyors and places them into the boxes of the active drawer.

Optionally a breakage control system including unload can be integrated in the area of the

infeed conveyor belts of the Unloader.

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Cluster Automation Equipment

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Carrier Loading and Unloading | SCHMID Carrier System

The wafers/cells are transferred between the single process steps in specially developed SCHMID

Carriers. The full carriers are loaded into the Carrier Loader which removes the wafers/cells out

of the cases to feed them into the following process equipment. In return the Carrier Unloader

receives the wafers/cells after the process and stores them into the carriers for the next transportation.

• Vibration-free, gentle and smooth wafer/cell transport

• Throughput up to 7000 wafers/cells per hour on up to 10 lanes

• Optional integration of breakage control, gap closing and tilting lance

• Wafer/cell tracking due to an optional upgrade with RFID chips

• Plug + Play installation

SCHMID Carrier

Light and solid material, warp resistant

Usable sunny side up and sunny side down

Different carriers for 5“ and 6“ wafers/cells

RFID chip integration possible

Stackable handling carrier with a capacity of 50 wafers/cells

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SCHMID Transport Trolley

Horizontal wafer/cell transport for 25 carriers

Vertical wafer/cell transport for 20 carriers

Integrated work plate for carrier preparation

Shock absorber for stressfree wafer transport

Carrier fixing

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Cluster Automation Equipment

MONTRAC Intra Logistic System

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Increasing productivity thanks to flexible and intelligent intralogistics

Montrac is an intelligent conveyor system for networking manufacturing and logistics pro-

cesses and represents the perfect solution for intralogistics in the PV industry. Smooth movement

and utmost flexibility will ensure perfect transport of carriers and boxes – upstream, downstream

or in between machines. Highly sensitive products are moved without jolts or vibrations. Montrac

interlinks processes, provides automated warehouse interlinkage, and optimizes the productivity

of solar production lines. Individual machines can be linked and synced with each other. Due to

its flexibility, the system is capable to prevent interruptions in production. In case a machine needs

to be serviced, Montrac will simply address another machine without interrupting the production flow.

Options

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Universal shuttle system

Montrac is a modular, universally usable transport system. The self-propelling shuttles are

maintenance-free. The electrically operated components (switches and crossings) do not

need pneumatics; for minimized power consumption their power is supplied directly via

power rails. The shuttles communicate with the track via infrared light.

Flexibility

All Montrac components have the same basis and are compatible with each other. All tracks

are available in any length. The bypasses, switches and curves have deliberately been kept

short so that the system can be perfectly customized to any space requirements. Thanks to

its monorails, Montrac can also run in curves with a very tight radius. There are virtually no

limits to the layout flexibility; systems can be expanded, modified or adapted as needed.

Usually the system is installed underneath the ceiling, on top of the machine, on pillars in

between the machines or in working height.

OFC – Overall Factory Control

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The Overall Factory Control is the high end SCHMID in-house software

solution for production and facility controlling. The comprehensive OFC system

offers multiple features for equipment monitoring, trend analysis, maintenance

planning or material tracking. The data is the base for many further steps like

process optimization.

Controlling tool for individual plants

Machine controlling on multiple floors

Production and wafer tracking

Controlling and documentation of single events and process parameters

Production flow monitoring and analysis

Avaiblilty and downtime controlling

Access from different workstations via Intranet or Internet

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Options

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OFC connection everywhere via Internet

Directly connected to PLC or to OPC server of the equipment

Equipment controller for data collection via OPC or XML OFC server with SQL and web server

Integrated Fab Solutions Covering the Whole PV Value Chain

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Within the framework of “Integrated Fab Solutions”, Schmid offers turnkey concepts ranging from

wafer and cell to module production. Optimum alignment of the individual production processes

along the entire value-adding chain reduces costs, improves quality, efficiency and in turn leads

to sustainably increased competitiveness. The value-adding chain is extended by the range of

SCHMID SILICON TECHNOLOGY products to even include polysilicon thereby becoming self-

contained.

Costs reduction due to

• Universal infrastructure

• Optimised building layout

• Consolidated logistics

• Increased purchase volumes

• Media consumption synergies

• Optimisation of processes in interface

areas based on a universal approach

of fully integrated technology and material

flow solutions

SCHMID Preview

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400 MW Integrated Fab Solution (Wafer, Cell and Module)

Wafer

Cell

Module

Gebr. Schmid GmbH + Co. | Robert-Bosch-Straße 32 – 34 | 72250 Freudenstadt | Germany | phone: +49 7441 538-0 | fax: -121 | info@schmid-group.com | www.schmid-group.com

08/2010 • Changes and errors excepted