Material to be Etched

Chemicals

Ratio

Comments

Aluminum (Al)

H₃PO₄ : Water : Acetic Acid : HNO₃

16:2:1:1

PAN Etch;

200 nm/min @ 25 C;

600 nm/min @ 40 C

Aluminum (Al)

NaOH : Water

1:1

may be used at 25 C but etches faster at a higher temperature

Aluminum (Al)

H₃PO₄

---

must be heated to 120 C

Chromium (Cr)

HCl : Water

3:1

---

Chromium (Cr)

HCl:Glycerin

1:1

---

Copper (Cu)

HNO₃ : Water

5:1

^---

Copper (Cu)

Ammonium Persulphate

---

---

Gold (Au)

KI : I : Water

115 g : 65 g : 100 ml

---

Gold (Au)

HCl :  HNO₃

3:1

Aqua Regia;

discard after use

Iron (Fe)

HCl : Water

1:1

---

Iron (Fe)

HNO₃ : Water

1:1

---

Lead (Pb)

Acetic Acid : H₂O₂

1:1

for dissolving solder connections

Lead (Pb)

Acetic Acid : H₂O₂ : Water

2:2:5

^---

Molybdenum (Mo)

HCl : H₂O₂

1:1

---

Molybdenum (Mo)

H₂SO₄ : HNO₃ : Water

1:1:1

^---

Nichrome

H₂SO₄

---

use at 100 C

Nichrome

HCl :  HNO₃ : Water

1:1:3

---

Nickel (Ni)

HCl :  HNO₃

5:1

 ---

Nickel (Ni)

HF:  HNO₃

1:1

 ---

Palladium (Pd)

HCl :  HNO₃

3:1

Aqua Regia;

discard after use

Platinum (Pt)

HCl :  HNO₃ : Water

3:1:4

use at 95 C

Platinum (Pt)

HCl :  HNO₃

8:1

age for 1 hour;

use at 70 C

Polysilicon (Si)

HNO₃ : Water : HF

50:20:1

remove oxide first;

540 nm/min @ 25C

Polysilicon (Si)

HNO₃ : HF

3:1

remove oxide first;

high etch rate:

4.2 micron/min