Application of a high temperature MagLev pump system in a SPM bath recirculation

Transcription

1 Application of a high temperature MagLev pump system in a SPM bath recirculation Michael Einspender 1,Berthold Reimer 1, Torsten Radtke 1, Marco Brunner 2 1 GLOBALFOUNDRIES 2 LEVITRONIX 11th April 2013

2 Table of content Motivation 1:1 Replacement of a Pulsation Pump Problems at certain SPM conditions Solutions Results for SPM with an advanced Installation of a MagLev pump system Particle and VPD Results Summary April 10, 2013

3 Motivation Recirculated SPM in a batch tool is since beginning of semiconductor manufacturing used for Post Implant Cleaning and resist stripping. Cleaner Chemistries and lower pore size of the filters is used to meet the requirements for higher Integration. A stable flow rate should also be part of a stable process. With a pneumatic drive pump a constant flow rate is not easy to realize. The only parameter for this kind of pump system is the pump pressure. The calculated flow rate by the number of pump strokes does not consider gas bubbles and filter ventilation. A change in the viscosity, higher gas amount and filter resistance will result in a change of the flow. The aim is a recirculation pump system which is independent from all these parameters and results in a constant flow. April 10, 2013

4 Flowchart and results with 1:1 Replacement of a the Pneumatic bellows pump Recirculation area with a MagLev pump system Levitronix Pump Heater Filter Flowmeter Flowmeter in the recirculation line Simulated Proximity Sensor A Simulated Proximity Sensor B Controller Flow controlled by feedback of the flowmeter signal The signal of the bellow pump is simulated by the pump Controller. No software modification was necessary. April 10,

5 Flowchart and results with 1:1 Replacement of a the Pneumatic bellows pump Flow rate at with constant pump settings of 4000 rpm With constant 4000 rpm a flow rate of ~17.5 l/min can be reached with 5:1 90 C SPM. With 120 C 5:1 SPM the flow rate is for first 2 hours after bath change is very low, because of a lot of gas bubbles in the recicurlation line coming from the decay of the H2O2. Than suddenly the flow rate increased to ~22.5 l/min and the amount of bubbles is drastically reduced. The higher flow rate of 120 C SPM compared to the 90 C SPM is propably coming from the lower viscosity. April 10,

6 Movie: MagLev Pump with 1:5 120 C after liquid change April 10, 2013 Confidential 6

7 Movie: MagLev Pump with 1:5 120 C 6h after liquid change April 10,

8 Movie: Bellow pump with 1:5 120 C after liquid change April 10,

9 Movie: Bellow Membran pump with 1:5 120 C 6h after liquid change April 10,

10 Theoretical consideration for Improvement 2 pumps in a row Two filters in parallel 3/4 piping partly changed to 1 piping April 10,

11 Flowchart with 2 MagLev pump system The Pump 2 is running with a 25% higher rpm than Pump 1 April 10,

12 Pressure Drop in front of filters Possible flow with 1 Pump and 1 filter Target flow rate 20lpm can be reached With 2 pumps and 2 filters Theoretical modell can be confirmed with the empirically determined values April 10,

13 Results with 2 MagLev pump system 5:1 SPM 5:1 at 120 C after bath change. Flow rate is regulated to target of 20 l/min by pump speed Pump Speed is adjusted for a stable Flow rate Bath life 1h Bath life 6h April 10,

14 Movie: MagLev double pump system 1h after Liquid change April 10,

15 Movie: MagLev double pump system 3h after Liquid change April 10,

16 Pressure Drop In Front Of Filters after bath change April 10,

17 Pressure Drop in front of filters April 10,

18 Particle and VPD results Adders > 50nm (SPM + APM) Bellow pump MagLev pump SPM + APM Analysenbericht Wafer 300 VPD PNS Levitronix other pump Einheit Al E+10 Atome/cm2 Ba < < E+10 Atome/cm2 Be < < E+10 Atome/cm2 Bi < < E+10 Atome/cm2 Ca < < E+10 Atome/cm2 Cd < E+10 Atome/cm2 Ce < < E+10 Atome/cm2 Co < < E+10 Atome/cm2 Cr < E+10 Atome/cm2 Cu < < E+10 Atome/cm2 Fe < < E+10 Atome/cm2 Ga < < E+10 Atome/cm2 Ge < < E+10 Atome/cm2 Hf < E+10 Atome/cm2 In < E+10 Atome/cm2 K < E+10 Atome/cm2 La < < E+10 Atome/cm2 Li < < E+10 Atome/cm2 Mg < E+10 Atome/cm2 Mn < < E+10 Atome/cm2 Mo < E+10 Atome/cm2 Na E+10 Atome/cm2 Nb < < E+10 Atome/cm2 Ni < E+10 Atome/cm2 Pb E+10 Atome/cm2 Sb < < E+10 Atome/cm2 Sr < E+10 Atome/cm2 Ta < < E+10 Atome/cm2 Ti E+10 Atome/cm2 V <0.009 E+10 Atome/cm2 W E+10 Atome/cm2 Y < < E+10 Atome/cm2 Zn E+10 Atome/cm2 Zr < E+10 Atome/cm2 April 10,

19 Summary For a low H 2 O 2 concentrated or low temperature SPM bath only 1 MagLev pump can be enough. For a high H 2 O 2 concentrated and high temperature SPM two MagLev pumps in a row and a reduced flow resistance by 2 Filters in parallel are needed to get an improved flow over the bath life time. Constant flow rate over the complete bath life time can be achieved, independent from any other parameter like viscosity, pressure drop and gas content. VPD and defect results are comparable. April 10,

20 Expression of Thanks Niklas Krumm, Torsten Radtke and Simon Stöckli for initiating the project Michael Einspender for all the hardware changes, collecting the data and making the movies Marco Brunner for the excellent support April 10, 2013 Confidential 20