๋ณธ๋ฌธ ๋ฐ”๋กœ๊ฐ€๊ธฐ

๋ฐ˜๋„์ฒด ๊ณต๋ถ€

[Etch ๊ณต์ • ์‹ฌํ™” 5] Etch ์žฅ๋น„, ๋ถˆ๋Ÿ‰ ์‚ฌ๋ก€

โ–  Etch ์žฅ์น˜์˜ ๊ตฌ์„ฑ ์š”์†Œ

* Pump

- Dry Pump (QDP) : ๋จผ์ € ์ ๋‹นํžˆ ์ง„๊ณต (sub Fab)

- TMP (Turbo Molecular Pump) : ๊ณ ์ง„๊ณต

- Scrubber : ๋ฐ˜๋„์ฒด ๊ณต์ •์—์„œ ๋ฐœ์ƒ๋œ ์ž”๋ฅ˜ ์œ ํ•ด gas๋ฅผ ๋ฌดํ•ด gas๋กœ ๋ณ€ํ™˜ ๋ฐฐ์ถœํ•˜๋Š” ์žฅ์น˜

 

* RF Generator

* Chiller : ๋ฐœ์ƒ ์—ด ๋ƒ‰๊ฐ์‹œ์ผœ ์‹๊ฐ์˜ ๊ท ์ผ๋„ ๋ฐ Damage ๊ฐ์†Œ ์‹œํ‚ค๋Š” ๊ธฐ๋Šฅ

* ESC (Electro Static chuck) : ์ •์ „๊ธฐ์  ํž˜์„ ์ด์šฉํ•˜์—ฌ W/F ์žก์•„์ฃผ๋Š” ์—ญํ•  

* Process Chamber

* Gas Box : Gas ์œ ๋Ÿ‰ ์กฐ์ ˆ by MFC

* Main Controller

* ์ง„๊ณต ; ์ผ์ • ๊ณต๊ฐ„๋‚ด์˜ ๋ถ„์ž๋ฅผ ๋Œ€๊ธฐ์•• ์ดํ•˜๋กœ ์ œ๊ฑฐํ•œ ์ƒํƒœ (๋‹ค๋ฅธ ๊ธฐ์ฒด๋“ค์ด ์ œ๊ฑฐ๋œ ๊ณต๊ฐ„)

- ๋ถˆ์ˆœ๋ฌผ๊ณผ ๊ธฐํƒ€ ๊ธฐ์ฒด ๋ถ„์ž๋“ค์„ ์ œ๊ฑฐํ•˜์—ฌ ๊นจ๋—ํ•œ ์ƒํƒœ์—์„œ ์ˆœ์ˆ˜ํ•œ ๋ฐ˜์‘์„ ํ•  ์ˆ˜ ์žˆ๋„๋ก, ์ƒ์‚ฐ์„ฑ์„ ์ข‹๊ฒŒ ํ•˜๊ธฐ ์œ„ํ•ด ์‚ฌ์šฉ

- 1atm = 760Torr = 760mmHg = 1013mbar = 101.3kPa

 

* MFP (Mean Free Path) ํ‰๊ท  ์ž์œ ํ–‰๋กœ

- ํ•œ ์ž…์ž๊ฐ€ ๋‹ค๋ฅธ ์ž…์ž์™€ ์ถฉ๋Œํ•˜๊ธฐ ์ „๊นŒ์ง€ ์ด๋™ํ•œ ํ‰๊ท  ๊ฑฐ๋ฆฌ

 

 

โ–  Ashing

- PR ์ œ๊ฑฐ : Dry ashing(O2 Plasma, 250โ„ƒ-cooling ํ•„์š”) + Wet strip (ํ™ฉ์‚ฐๅคš) + DIW RInse

- ์กฐ๊ฑด -

โ‘  PR์ด ์™„์ „ํžˆ ์ œ๊ฑฐ ๋˜์–ด์•ผ ํ•จ.

โ‘ก Rinse ๊ณต์ •์œผ ํ†ตํ•ด ์›จ์ดํผ์—์„œ ์ œ๊ฑฐ

โ‘ข ์›จ์ดํผ ํ‘œ๋ฉด์ด๋‚˜ ๊ธฐํŒ์„ ์†์ƒ์‹œํ‚ค์ง€ ๋ง์•„์•ผ ํ•œ๋‹ค. 

 

- Ashing : Plasma ashing & O3 Ashing ๋งŽ์ด ์‚ฌ์šฉ

- Strip

  : Metal ๋ฐฐ์„  ์ด์ „ - H2SO4 + ๊ณ ์ˆœ๋„ H2O2 ํ˜ผํ•ฉ์•ก

  : Metal ๋ฐฐ์„  ์ดํ›„ : ์œ ๊ธฐ Strip

 

* Metal ๊ณต์ • ์ „ํ›„ ๊ตฌ๋ถ„ : Cross Contamination ๋ฐฉ์ง€

 

 

โ–  Etch ๋ถˆ๋Ÿ‰ ์‚ฌ๋ก€

 

1) Etch Rate Uniformity in wafer

Wafer ๋‚ด์—์„œ ์œ„์น˜๋ณ„ etch rate ๊ด€๋ฆฌ(Uniformity)๊ฐ€ ๊ฐ€์žฅ ์ค‘์š”ํ•จ

ex) ํ™˜ํ˜•์„ฑ ๋ถˆ๋Ÿ‰ fail (Center ์ชฝ etch rate high / Edge ์ชฝ etch rate low) - Unif +- 3.0%

=> Center ์ชฝ Tr ๋™์ž‘ fast (Channel length  ์ฐจ์ด๋กœ ์ธํ•ด)

=> Center / Edge ๊ฐ„์˜ ์ฐจ์ด ์—†์• ์ค˜์•ผํ•จ!!

* ์ฃผ์š” ์›์ธ : Chuck ์˜จ๋„์˜ Uniformity, Gas flow rate, ์••๋ ฅ, Dispense arm movement, chemistry type ๋“ฑ

2) Pattern collapse

- ACI ์ƒํƒœ์—์„œ CD ์ธก์ • (KLA)

- ํŒจํ„ด์ด ๋ง๊ฐ€์ง.

- Center/Edge ๊ฐ„์˜ ์‹๊ฐ ์กฐ๊ฑด์ด ๋‹ฌ๋ผ์„œ..

 

3) Reticle ๊ธฐ์ธ์„ฑ Bridge

- ์›ํŒ ํŒจํ„ด์ธ Reticle ์ž์ฒด์˜ ๋ฌธ์ œ

- 1. Revision, 2. Zapping(๋ ˆ์ด์ €๋กœ ๊นŽ์•„๋ƒ„)

 

4) Particle ์„ฑ Pattern ๋ฐ€๋ฆผ

- Particle = P/C 

- ๊ณต์ •์„ฑ P/C (์›ํ˜•)

- ์„ค๋น„์„ฑ P/C (๊ฐํ˜•)

 

*WAC (waferless auto cleaning) : ๊ณต์ • ์ง„ํ–‰ ์ „ ์ฑ”๋ฒ„ Cleaning

 

5) ๊ธฐํƒ€ ์—ฌ๋Ÿฌ defect 

- scratch, particle...

 

 

* Contact not open (Blocked contact)

* TSV ์‹œ Etch loading effet 

- etch depth ์ฐจ์ด 

- ํ•ด๊ฒฐ์ฑ… : Ar flow rate chlwjrghk

 

* HAR(High Aspect Ratio) Contact Etch Issue

1) Bowing ์ธก๋ฒฝ etch

2) Twisting

 

- Cause : Electric field  buildup due to charge deposition

  high energy electron effect on feature twisting in SiO3 etching over Si

  => Increase high energy electron flux and energy to further neutralize positive charge on trench bottom and sidewalls.

  => control ion energy as etch proceeds to utilize selectivity difference between PR and SiO2 etching

 

* Undercut

- Etch rate๊ฐ€ ๋†’์œผ๋ฉด undercut์˜ ์ฃผ๋œ ์›์ธ์ด ๋จ. 

- ํ•ด๊ฒฐ์ฑ… : ๋™์ผํ•œ etch/deposition time ratio

 

* Footing (Lateral undercut)

- Charge accumulation at the insulator (+์ด์˜จ๋“ค์ด ์˜†์œผ๋กœ ์น˜๊ณ  ๋“ค์–ด๊ฐ„๋‹ค.)

  => electron์œผ๋กœ ์ค‘ํ™”์‹œ์ผœ์ค˜์•ผํ•จ.

 

* Patterning defect (metal blocked etch)

- etch mask ํ˜•์„ฑ ๋ถˆ๋Ÿ‰ (ADI pattern ๋ถˆ๋Ÿ‰, particle)

 

* Via Unetch (open defect) 

-Via: Contact ์ €ํ•ญ์„ ์—†๊ฒŒ

- ์›์ธ : Etch margin ๋ถ€์กฑ, blocked particle

 

 

 

โ–  Cleaning ๋ถˆ๋Ÿ‰

* Polymer residue

- Ashing ํ›„ strip ๊ณผ์ •์—์„œ PR ์ œ๊ฑฐ => PR 

 

* Pinhole defect

 

 

โ–  Etch ์—”์ง€๋‹ˆ์–ด

 

<๊ณต์ •์—”์ง€๋‹ˆ์–ด>

์ˆ˜์œจ ํ–ฅ์ƒ & ์ƒ์‚ฐ์„ฑ ํ–ฅ์ƒ!!

- Etch ๊ณต์ •์˜ ์ž…๋ ฅ/์ถœ๋ ฅ ๋ฐ์ดํ„ฐ ๊ด€๋ฆฌ ๋ฐ ๋ถ„์„

- Etch ๊ณต์ • ๊ฐœ์„  ๋ฐ ๊ฐœ๋ฐœ

- ์ˆ˜์œจ ๋ถ„์„ ๋ฐ ๊ฐœ์„  ํ–ฅ์ƒ

- Etch ๊ด€๋ จ ๋ถˆ๋Ÿ‰ ๋ถ„์„ ๋ฐ ๊ฐœ์„ 

<์„ค๋น„ ์—”์ง€๋‹ˆ์–ด>

- ๋ณด์ˆ˜/์œ ์ง€ => ๊ฐ€๋™๋ฅ  ๋†’์—ฌ์„œ ์ƒ์‚ฐ์„ฑ ์ˆ˜์œจ ๊ด€๋ฆฌ