Post on 18-Mar-2018
Advanced wafer processing: Ready for the new PV generation 5th Annual c-Si PVMC Workshop
13.7.2016 – Christoph Eggimann
C B
E
D
A
The new PV generation
SmartWire Connection (SWCT)
TCO layer and wafer thickness
suitable for SmartWire
80% less silver
Higher energy yield
Higher efficiency
Longevity and micro-crack resistant
E
Adapted test metrology
High cap cells
Busbarless cells
DragonBack
PED (chipping)
Single wafer
tracking
Quality & performance
control
B
Diamond wire
Thinner wafer Lower
costs
A
High efficiency
Lower system cost (BOS)
Independent of wafer
thickness
Only 6 process steps
Low CoO
Temperature coefficient
Higher energy yield
Bifacial Higher
energy yield
Heterojunction (HJT)
Texture
a-Si front/rear side
Test & sort
TCO / metal rear contact
Print front side
Curing
C
D
Meyer Burger / 12-2015 2
Enabling wafer technologies
3
Wafer Inspection Slicing
Technology Diamond Wire
Bricking
Technology
Bricking Technology: Integration and
Automation for minimized production cost
4
Manpower-efficiency 1 man operation – fully automated
Space-efficiency 50% less space for equipment and
buffers
Process-efficiency diamond wire / water only / glue free
Material-efficiency 0.42mm kerf silicon savings
PV wafering evolution
Kerf µm 150 150 150 120 <90
Time hrs 8 4 3 3 2
DW Use m/Wf 2 1.2 1 1
Capacity MW 10 15 16 17 30
Diamond Wire
Management System
(DWMS)
2009 2010 2011 2012 2013 2014 2015 2016
Slurry Saws
Newest Generation
Diamond Wire Saw
Pe
rfo
rma
nce
DW Upgrades
Based on Mono 156 x 156 x 0.18 mm Wafers
Dedicated DW Saws
500 MW fab yesterday and today
6 6
Conventional Slurry
Wire Saws
Latest Generation
Diamond Wire Saws
Challenge
DW Wafering Cost of Ownership:
Diamond Wire consumption is the
biggest cost driver
(approx. 50%)
Diamond wire consumption is
influenced by wire wear:
1. CWW = wear from cutting
2. NCWW = wear from winding
Wire Consumption Matters
7
Wafering Cost of Ownership
Wire
Operator
Depreciation
Cutting fluid
WGR
Electricity
Glue
Beam
Spare parts
8
Diamond Wire Management System (DWMS)
Conventional Wire Management
Storage
(Supply) Area
Working
(Winder) Area
How to improve wire performance
check base data
10 µm less silicon
>100’000 USD/yr Savings per machine
Challenge: How to capture this
cost saving potential?
What is the Impact of Thinner Wires?
10
90 µm 100 µm
70 µm wire
80 µm
80 µm wire 60 µm wire
Tight Wire Tension Control
Wire Tension Decoupling
Thin wires require improved tension control
11
± 0.5 N
Dedicated Wire Development
Low Inertia Pulleys
Enablers of thin wire slicing Tensio
n Limit
Tight wire
tension control
Diamond Wire
Management
System
Enables thin
wire slicing Conventional
Technology
DWMS
Technology
High performing wire with consistent quality enables higher yields
13
Meyer Burger Diamond Wire
• Coordinated wire, equipment and process
development premium performance
• Manufacturing controls, detection algorithms,
automatic feedback loops improved quality
Cut Nr
TT
V L
ine
(u
m)
Spool 1 Spool 2
Sample TTV Data
Mono 156 / 70 um wire / 1 m/Wf / <2 hr cut time
Fast cut
Mono 156 *) process in development
Mono DW Sample Process
14
0.0
0.5
1.0
1.5
2.0
2.5
95
96
97
98
99
100
0 5 10
Cu
t T
ime
(h
rs)
Wir
e C
on
su
mp
tio
n
(m/w
f)
Sa
w Y
ield
(%
)
Cut Nr
Saw Yield Cut time
Wire consumption
Low wire
usage*
m/Wf hrs
Wire
usage
Cut
time
2 1
3 0.5
Mono fast cut sample results 70 µm wire
80 µm EPW
Multi 156
Multi DW sample process
15
m/Wf hrs
Wire
usage
Cut
time
< 3 1.8 Multi cut sample results 80 µm EPW
0.0
1.0
2.0
3.0
4.0
5.0
95
96
97
98
99
100
0 2 4 6
Cu
t T
ime
(h
rs)
Wir
e C
on
su
mp
tio
n
(m/w
f)
Sa
w Y
ield
(%
)
Cut Nr
Saw Yield Cut time
Wire consumption
TC
O (
US
Dc
/Wf)
Comparing Mono and Multi as-cut wafer total cost of ownership
On per wafer basis, Mono wafer cost on par with Multi
On per Watt basis, mono wafers cost can already be lower than multi
Key drivers are
• Mono vs. Multi brick cost
• Wire cost
• Throughput effects
Assumptions
Mono: 70 um fast cut process; 180 um thickness; 27 USD/kg brick,
Multi: 80 um EPW process; 200 um thickness; 20 USD/kg brick
Multi DW vs. Mono DW Wafer TCO comparison
16
Effect of higher
Mono ingot cost Wire
usage
Effects of higher throughputs
Higher throughputs for Mono driven by faster cutting times and higher number of wafers per mm (thickness, kerf)
Nr of wire saws for Mono reduced compared to Multi
Assumptions
Mono: 70 um fast cut process; 180 um thickness;
Multi: 80 um EPW process; 200 um thickness
Multi DW vs. Mono DW Wire saw capacity comparison
17
0
100
200
300
400
500
600
0 5 10 15 20 25 30
Ca
pa
cit
y (
MW
/yr)
Nr of Machines
Multi Mono Target Capacity
TC
O (
US
Dc
/Wa
fer)
Why is Quality Relevant?
18
Challenge:
Biggest levers for
further TCO
reductions
• Wafer
thickness
• Yield /
Inspection
156 Mono / 180 µm / 70 µm wire
Wafer TCO contributors
Quality is critical to enable further cost-downs
Slicing machine setup
Optimized handling
High quality processes
High quality inspection
Levers to improve slicing quality
19
New TFC Technology
Standard NVCD Technology
How to detect microcracks accurately? Transflection TFC technology
20
Transflection technology increases visibility of microcracks and therefore
minimizes misjudge rate
Challenge edge chips / Perpendicular edge detection
21
• Perpendicular Edge Detection technology
Wafer
edge defect
17
5µ
m
65
µm1
75
µm
90 µm
Near-Term Challenges (1-3 Years)
Please identify/describe your top near-term challenges for the adoption of Advanced Wafering Techniques as it relates to your position in the supply chain
• Improving material utilization via thinner wire diameters (wires, process, machine) as well as thinner wafers
• Providing qualified wafers for next gen PV technologies
• Adoption of diamond wire slicing for Multi crystalline silicon (DW slicing, texturization)
Long-Term Challenges (4+ Years)
Please identify/describe the top long-term challenges for the adoption of Advanced Wafering Techniques as it relates to your position in the supply chain
• High maturity of classical wafering technologies (high throughputs, yields, low costs) may lead to lower capex pool
• Industrializing alternative wafering technologies (kerf free)
• Need for yet higher degrees of automatization, integration and intelligence
Thank you for your attention
Visit us at Intersolar booth 7521 – West Hall
24