BUEE 2013 AMC countermeasure in future high tech Fabs

Transcription

1 M+W High Tech Projects Taiwan Co., Ltd. A Company of the M+W Group November 29 th, 2013 Michael Gall BUEE 2013 AMC countermeasure in future high tech Fabs

2 AMC- countermeasure in future Fabs 1. AMC definitions & specifications a) Definition according SEMI F21-95 b) Relevant industries c) Specification of concentration limits / ITRS d) Critical processes & AMC impact 2. AMC countermeasures a) Prevention b) Separation c) AMC Filtration 3. AMC filter concept for future Fabs 1. Impact of efficiency & capacity 2. Regeneration & waste reduction

3 Short introduction to AMC? AMC means Airborne Molecular Contamination International classification according to SEMI F21-95 A Acid (SO2, HCl, HF, Nitrogen oxides NOx,.) B Base (NH3, Amines ) C Condesables (Volatile Organic Compounds = VOC) D Dopant (Phosphorus and boron compounds) = Chemical element which even as trace part can modify the electrical proprieties of a semiconductive material) A fifth category is currently being introduced into the practice of contamination control Refractories (Organic substances except CHON compounds) like Si (Siloxanes), S, P 3

4 Categories of AMC and typical compounds (SEMI F21-95) 4

5 AMC - Market Overview AMC high importance AMC low importance (Current situation) Semiconductor Nanotechnology Hard disc PV fabs Pharmacy Flat Panel Food fabs Medical technology Transistor technology with more and more thinner layers => the most vulnerable target for air contamination

6 AMC specification of concentration limits According different process AMC sensitivity and different process setup there are no general specification of AMC limits in cleanroom Most semiconductor companies define their cleanroom concentration on their own. As recommendation values the International Technology Roadmap for Semiconductor (ITRS) can be taken. Their values are updated regularly, current version is 2011 ( 2012 just update version, 2013 not yet released) According latest ITRS, AMC specification levels will not have big changes in future New processes (like EUV) will have more AMC requirement in future but unlikely will influence Fab design 6

7 AMC Impacts, Risks and Specifications - Overview AMC Classes Damaging mechanisms Sensitive Processes A Total acids incl. org. acids (as SO 2 ) Corrosion Nanoparticle haze generation Risk Classes Recommended Specifications 1) [µg/m³] Photomask exposure (Mask room) 1 10 Metrology 1 10 Lithography 1 10 CMP 5 2 Open metal- and copper processes 3 2 B Total bases (as ammonia) C Total VOC (Organic compounds, retention time GCMS Benzene, calibrated as Hexadecane) Particle generation T-Topping Nanoparticle haze generation on critical optical laser parts Nanoparticle haze generation on critical optical laser parts, particularly at middle and high molar mass GOI (Gate oxide integrity) Photomask exposure (Mask room) 1 5 Metrology 1 5 Lithography 1 5 CMP 5 5 Photomask exposure (Mask room) Metrology Lithography Gate-Oxide /High temperature furnace D Dopants (as hexadecane) Modifying of the electrical properties by uncontrolled Doping Gate-Oxide /High temperature furnace 4 0,1 Refractory's (as Hexadecane) Haze generation in generally and especially on critical optical laser parts Lithography 1 1 Metrology 1 1 Risk class: 1-5, high lo low n.a. = not applicable 1) = according to the specifications of tool suppliers and ITRS road map, respective

8 Extract ITRS Roadmap Lithography

9 Extract ITRS Roadmap 2011 Reticle /Gate Furnace

10 Typical Concentration Ranges in Cleanroom Summary by M+W group experience in different projects: Reported damage in sensitive areas Reported damage in general areas Acids Spec smell Conclusion: Bases Spec smell - very different concentrations for sensitive and general areas Condensables Dopants Spec Spec smell smell - To be considered at the design of the air flow system (not all areas need the same strong filtration) Refractories Spec smell ng/m 3 µg/m 3 mg/m 3 g/m 3 Values in cleanroom and in the outside air are hatched

11 AMC- countermeasure in future Fabs 1. AMC definitions & specifications a) Definition according SEMI F21-95 b) Relevant industries c) Specification of concentration limits / ITRS d) Critical processes & AMC impact 2. AMC countermeasures a) Prevention b) Separation c) AMC Filtration 3. AMC filter concept for future Fabs 1. Impact of efficiency & capacity 2. Regeneration & waste reduction

12 Sources of AMC 12

13 AMC countermeasure prevention Most effective way is to reduce AMC contamination is to prevent the contamination by knowing and controlling the sources. Not existing AMC contamination don't need to be purged / filtered Some AMC (e.g. low boiling) are easy to purge or dilute but difficult to filter Some AMC (e.g. high boiling, surface sticking AMC) are very difficult to clean up and will be a long term AMC source while operation. 13

14 AMC prevention design & construction Phase AMC contamination should be considered: from the very beginning of Fab design Scrubber & Exhaust design efficiency stack height location Construction material choice Approve outgassing behavior Construction phase Sufficient venting of outgassing material, Income check (e.g. with ppbrae) Fab purging Control manpower 14

15 AMC prevention - separation Unlike Particle movement, AMC contamination can move vertical or even against airflow direction. Any contamination easily can impact other process areas even there is some distance in between Similar AMC sensitive processes should be located at same place and equipped with certain AMC filter setup These areas should be separated in cleanroom, subfab and truss area in order to avoid mixing of different AMC air qualities 15

16 AMC prevention operation phase Internal source control Right exhaust adjustment avoid AMC contamination from process chemicals Move in material check (outgassing issue) Prevent leakage, spills while maintenance Online AMC monitoring for fast emergency response AMC filters 16

17 AMC filtration Even source control will reduce contamination levels end extend AMC filter lifetime, the usage of AMC filters will be necessary AMC filters can be designed for one single contamination type or for several contamination types. However. Each AMC type needs special AMC filter media AMC filters are available in different shapes for different usage area. Most common types are used in MAU and In the recirculation air Combined or integrated in process tools Combined or integrated in supply tools (e.g. compressors, vacuum pumps) 17

18 Available AMC filtration Technologies: Organics Inorganics (Acids & Bases) Unimpregnated carbon Impregnated carbon WAC/WBA SAC/SBA Removal efficiency Removal capacity Desorption behaviour Adsorption Chemisorption Ion exchange low boiling VOC SAC Strong acid cation exchanger WAC Weak acid cation exchanger SBA Strong base anion exchanger WBA Weak base anion exchanger

19 AMC filtration outside sources Outside air control Avoid shortcut with Fab exhaust MAU include air washer + AMC filtration steps Air washer Typical MAU outlet conc.: Bases < 1ppb Acids < 1ppb TOC < 10ppb Typical AMC filter efficiency: ~ 90% Airflow direction Typical Air washer efficiency: ~ 90% 19

20 AMC filter installation possibilities Makeup Air Unit Makeup Air Makeup Air Filters FFU Filters Minienvironment Filters Toolmounted Filters CDA Filters Control Panel T H P T H P Process Equipment Scanner XCDA Cleanroom Return Air Filters Compressor Subfab 20

21 AMC filters type overview MAU Type V- shape FFU / Tool type Box type Cylinder / Cartridge shape Modular frame type 21

22 AMC- countermeasure in future Fabs 1. AMC definitions & specifications a) Definition according SEMI F21-95 b) Relevant industries c) Specification of concentration limits / ITRS d) Critical processes & AMC impact 2. AMC countermeasures a) Prevention b) Separation c) AMC Filtration 3. AMC filter concept for future Fabs 1. Impact of efficiency & capacity 2. Regeneration & waste reduction

23 AMC concept for future Fabs In general there will not be a big change in Fab design between 300mm and 450mm technology, therefore the general AMC setup also will not change. Smaller structures will lead to more AMC sensitivity, this will also impact AMC cleanroom specification limits even not yet seen in ITRS roadmap so far. Lower AMC specification limits will soon require new media since adsorption at sub ppb level and desorption phenomenon will limit current medias. Most material with high efficiency (> 95%) will not have a very high capacity. This will probably lead to a 2 stage AMC filtration: 1 st stage: one high capacity filters 2 nd stage: high efficiency filters 23

24 AMC filters usage method AMC filters just have a limited lifetime in between 3 month and 24 month depend on inlet concentration and efficiency specification AMC filter weight is in between 10kg and 25kg So using AMC filters just one time will cause a high amount of waste that has to be considered as chemical waste Depend on AMC filter media and design some be regenerated. M+W group has more than 5 years experience in regenerating TOC, ammonia and acid filters already. Some filters already have been regenerated for 8 times with a total filter usage time of 5 more than 5 years 24

25 Regenerating of AMC filters 25

26 Summary AMC reduction by 3 main countermeasures: Prevention Separation Filtration For future high tech Fabs all AMC sources need to be controlled Outside sources Air washer + AMC filters Inside sources material control + process control + AMC filters Most types of AMC already AMC filter solutions available Lower AMC cleanroom specification will lead too more AMC filter stages and more AMC filtration locations increase of AMC filter usage 26

27 Thank You Contact: Michael Gall AMC Manager Phone , Mobile