ALMT - VitaNova

For Finishing Si Wafers

VitaNova Premium

For LT/LN Wafers

VitaNova Masspower

Contributes to Improvement of Yield Ratio Through Low-Damage Processing

Contributes to Improvement of Wafer Quality by Low-Load Grinding

Ultra ne diamond grit and Ultra ne ceramics revolutionized the conventional wisdom of grinding wheels. Application of both acquired material technology and production technology has allowed Ultra ne grinding. Its effectiveness to reduce grinding damage in layers of brittle material such as polish-reduction of 12-inch silicon wafer and prevent cracks on a thin layer device wafer.

Because fragile LT wafers used as the SAW lter tend to get broken in processing, improving the processed surface roughness is required. "VitaNova Masspower", having a high porosity abrasive layer with excellent durability of sharpness, provides low-damage processing enabled by the added body shape with a function of efciently feeding to the grinding point.

Features • Extremely at, low damage, and smooth grinding possible. • Grinding of 12-inch silicon wafers as thin as 3 µm is possible. • Polished surface quality equivalent to polishing is possible.

Features • High porosity abrasive layer for long sharpness retention. • Newly developed body shape to uniformly supply grinding uid to grinding points. • Highly efcient and high quality grinding.

Masspower

Conventional Wheel

φ 160–350

φ 160–350

Outside Diameter D (mm)

Outside Diameter D (mm)

12-inch Si Wafer / Comparison Data by Grain Size Grain Size

Grain Layer Width W (mm)

3

Grain Layer Width W (mm)

3

Self- Sharpening

Grain Layer Thickness X (mm) 5–10

Grain Layer Thickness X (mm) 3–10

1 µm

0.5 µm

LT

LT

#6000–#10000 (1–0.3 µm)

Grit Size (Grain Size)

#6000–#8000 (1–0.5 µm)

Grit Size (Grain Size)

Sa:2.8 nm PV:22 nm

Sa:1.5 nm PV:12 nm

By controlling the abrasive retention force, no signicant force is required for self-sharpening Shedding with a small amount of abrasive

Signicant force is required for self-sharpening Shedding by a group of abrasive grains

Comparison in LT Wafer Processing (Index with Conventional Product as 100)

Photo of the Fallen Bond

Surface Roughness

Magic Mirror Topography

Wafer Thinning Example (25 µm)

110

110

2 µm

50 µm

100

100

Grinding Wheel

Grinding Wheel

90

90

80

80

Surface Damage Depth

Body Shape

70

70

140 nm

230 nm

Water

Mist

60

60

Grinding Water Supplied to Grinding Point Uniformly LT Wafer

LT Wafer

0

0

Masspower

Conventional Wheel

For Si Bare Wafers

VitaNova Celled / V-Heart

For GaN / Sapphire Wafers

VitaNova Masspower

Demonstrates Performance in Si Bare Wafer Grinding

Achieves Mirror-Finish Machining of Hard Materials

It has a bond structure with high porosity and excellent chip evacuation, and achieves both lower load and longer life in the processing of silicon wafers. Features • Bonded structure with high porosity and excellent chip evacuation. • Achieved both Low load and long tool life in rough and semi-nishing of silicon wafers.

The adjustment of the binding grade and bond has enabled grinding of difcult-to-grind materials with ne grains that have been difcult to grind with conventional wheels. This wheel ensures high-speed and mirror nishing of GaN wafers.

Features • Grinding of difcult-to-machine materials. • High-speed and near mirror nishing.

φ 110–200

φ 160–350

Outside Diameter D (mm)

Outside Diameter D (mm)

3 (Cellfied) 3.4 (V-Heart)

Grain Layer Width W (mm)

3

Grain Layer Width W (mm)

Grain Layer Thickness X (mm) 3–10

Spindle Load Current (A)

Wheel Wear (µm/piece)

Grain Layer Thickness X (mm) 5

Grit Size (Grain Size)

#6000–#8000 (1–0.5 µm)

2

8

Grit Size (Grain Size)

#2000–#4000 (7–2 µm)

Approx. 20% Less

Results from Grinding Single-Crystal GaN Wafers GaN Wafer (Ga Surface) 2-inch

Approx. 40% Less

7

GaN Wafer

Sapphire Wafer

4-inch

Comparison with Conventional Products (Celled) Wheel Size φ 200-3 W

Sa=1.43 nm

Sa=1.41 nm

Grinding Process

Rough

Finish

Rough

Finish

1

6

Grit Size (Grain Size)

#2000 (7 µm)

#6000 (1 µm)

#2000 (7 µm)

#6000 (1 µm)

Specication

SD4000V

Stock Removal (µm)

50–100

10

50–100

10

Workpiece

12-inch Si Wafer

5

Feed Rate (µm/min)

30 60 90

20

30 60 90

20

Machine

Vertical rotary surface grinder

Wear Rate (%)

7 15 27

100

12 20 35

100

Wheel Rotation Speed 1,500 min -1

0

0

Cellfied

Cellfied

Conventional Wheel

Conventional Wheel

ー ー

ー ー

Chuck Rotation Speed 300 min -1

Surface Quality Ra (nm)

90

1–2

100

2

Grain Size 0.5 µm

Grain Size1 µm

5

6

Made with FlippingBook flipbook maker