1. Modified showerhead for the 450 mm wafer processing
Yuri Glukhoy
Nanocoating Plasma Systems Inc.
Fremont, CA USA 1

2. Showerhead-cooler system of a semiconductor-processing chamber for semiconductor wafers of large area US A1
Priority date Jan 25, 2014
METHOD FOR PROVIDING UNIFORM DISTRIBUTION OF PLASMA DENSITY IN A PLASMA TREATMENT APPARATUS
SHOWERHEAD-COOLER SYSTEM OF A SEMICONDUCTOR-PROCESSING CHAMBER FOR SEMICONDUCTOR WAFERS OF LARGE ARE A
TORCH SYSTEM FOR DEPOSITING PROTECTIVE COATINGS ON INTERIOR WALLS AND RECESSES PRESENT ON THE FLAT SURFACE OF AN OBJECT 2 3

3. The advantage of 450mm wafers is that while the equipment costs are frightening, the long-term production costs are advantageous. GlobalFoundries has done an extensive presentation on this - for a chip of a given size, a 450mm wafer can yield 3,400 dies while a 300mm wafer yields just 1,450.

5. Transition to 450 mm wafer can increase output twice

7. With ever increasing substrate sizes plasma uniformity becomes increasingly critical. Our design of the showerhead will help to develop the new uniform plasma processes
Magnitude of ion flux across 450 mm wafer
Average ion energy across 450 mm wafer

8. Proposed showerhead-cooler system of a semiconductor-processing chamber with uniform distribution of plasma density comprises showerhead with a plurality of thru gas holes that are coaxial with respective channels of the gas-feeding cooler plate. On the gas inlet side, the thru passages of the showerhead are provided with unequal conical nozzles characterized by a central angle that decreases from the peripheral part of the showerhead to the showerhead center. Such design provides uniformity of plasma density. Furthermore, in order to protect the walls of the nozzle and the walls of the gas holes from erosion that may be caused by the hollow-cathode phenomenon, these areas are coated with a thin protective coating that is resistant to electrical breakdown and chemical corrosion.

9. Patent application title: TORCH SYSTEM FOR DEPOSITING PROTECTIVE COATINGS ON INTERIOR WALLS AND RECESSES PRESENT ON THE FLAT SURFACE OF AN OBJECT
Inventor: Yuri Glukhoy (San Francisco, CA) Publication date: Patent application number:

10. Size of showerheads for 450mm wafer etching processing becomes commensurable with the wavelength
• High frequency and large area ⇒ standing wave effects
• High frequency and large area⇒ high density ⇒ skin effects
• High frequency and large area ⇒ high density ⇒ edge effects
Low frequency and large area – high voltage sputtering of showerhead

11. Unexpected cost of enlarging
Simple victorious transaction to the larger area of wafer after each 10 years established by Moore (Moore Law)appeared to be broken. Entrepreneurs explain it by economical issues. In reality, it is a scientific and technological issue related to commensurability of size and wavelength that we can solve

12. No more Moore LAM is scared
“We don’t want to go 450mm. We’ll never go 450mm“ said Dave Hemker, Senior Vice President and CTO at Lam Research “To me, if that’s the case, that’s almost the deal breaker right there.”
No more Moore

13. Applied is skeptical Robert Castellano:
“I have been very negative on 450mm diameter semiconductor wafer manufacturing, and have verbalized my analyses during two keynote presentations I gave at Semicon conferences in 2010 and My contention is that increasing wafer sizes is good for semiconductor manufacturers, but bad for semiconductor equipment manufacturers”

14. Good news from TEL
“we expect that the era of 450 mm wafers will arrive at some stage to support the ever-widening demand for semiconductors, so we will have to take steps to undertake the necessary preparations.”

15. Control of skin effect
• Skin effects =⇒ radial nonuniformities at high densities when
δ <∼ 0.45 √ dR
δ ∝ 1 √ n
= collisional or collisionless skin depth
d = bulk plasma half-thickness
R = discharge radius
1. M.A. Lieberman, J.P. Booth, P. Chabert, J.M. Rax, and M.M. Turner,
Plasma Sources Sci. Technol. 11, 283 (2002)

16. Standing wave affect
The ion flux is maximal at the centre due to standing wave affect The standing wave effect is seen at 60 MHz and is more pronounced at MHz

17. SUPPRESSION OF STANDING WAVE EFFECTS with shaped showerhead
• Shaped electrode (and duel plate) eliminate standing wave effects • Increased overall thickness in center compared to edge keeps voltage across discharge section constant • The electrode shape is a Gaussian, independent of the plasma properties L. Sansonnens and J. Schmitt, Appl. Phys. Lett. 82, 182 (2003). P. Chabert, J.L. Raimbault, J.M. Rax, and A. Perret, Phys. Plasmas 11,

18. Ion Flux Cartography showing where RF power is increased

19. Bell-like ion flux appears at a high frequency

20. Proposed by scientists to showerhead with a bell shape to correct uniformity of etching is a bad idea Experimental evidence of the suppression of the standing wave effect using the shaped electrode
propose
propose

21. Our answer to the shaping of the showerhead is re-distribution of the gas flow changing gas resistance of the gas holes on back side of the showerhead

22. Showerhead – cooling plate
Wafer
Entrance of holes should be protected from
breakdown
by yttrium oxide
coating
Electrostatic chuck
Cooing plate
Showerhead
Gap between a cooling plate and back side of showerhead is source of arcing during mismatching

23. Cooling plate with recess
Backside of cooling plate is joined to manifold and matching device
Space inside recess at a high RF electric field and a high gas pressure
is a perfect place for arcing during mismatching

24. Solution to mitigate adverse effect
Drilling of countersinks will improve etching uniformity in account of drawback – arcing and a hollow discharge inside the gas holes
Solution to mitigate adverse effect
we have developed two focusing atmospheric plasma inductively coupled deposition systems. A. generate 2mm deposition spot for a surface coating of the back side of the showerhead. B. generate 0.2 mm spot for a deep penetration of the gas holes

25. We can focus torch in order to deliver the vaporized nanoparticles and simultaneousely heat the substrate 25

26. Our invention - Saddle like RF Antennas that generate torch for vaporization of nanoparticles
Each antenna comprises two spiral coils in a mirror position and in a parallel connection. These coils are distributed with an angular uniformity and envelop a quartz tube of a plasma reactor. Such an non-axial symmetric design allows generation of a transversal RF field generating a wide plasma ball and prevents pinching of the torch

27. Our Double Torch provides a long resident time for injected axially nanoparticles for a total melting and vaporization. Top antenna kW at frequency MHz. Bottom antenna - 2 kW at MHz

28. Nanocoating System with CNC Fixture and Thickness Monitoring

29. Clusters contaminate deposition and increase a grain resistance
SEM picture of Yttrium oxide nanocoating 2500x 10 min 29

30. Clusters that are seen on the SEM picture in result of aggregation of nanopowder can be destroyed before entering the plasma torch using an atmospheric plasma dielectric barrier discharge .

31. We have developed an atmospheric pressure dielectric barrier discharge
with cold plasma for deaggregation of clusters
AP-DBD reactor with an argon plasma
at 50 W, frequency M Hz
and gas flow 10 lsm.

32. HIGH AP-ICP plasma jet for deep penetration of the gas holes

33. Nanopowder delivery using centrifuge with the double serpantine

34. Total view of an AP-ICP jet for a sub-millimeter focusing of a deposition spot
Top torch is used for pre-heating of the injected nanoparticles before vaporization in the bottom torch

35. Large Area nanocoating system with three focused ICP atmospheric plasma jets for a rapid Y2O3 protection coating