Effect of Recycling Time on Stability of Colloidal Silica Slurry and Removal Rate in Silicon Wafer Polishing

2007 ◽  
Vol 44 (2) ◽  
pp. 98-102 ◽  
Author(s):  
Eun-Suck Choi ◽  
So-Ik Bae
Keyword(s):  
Silicon Wafer ◽  
Colloidal Silica ◽  
Removal Rate ◽  
Wafer Polishing ◽  
Silica Slurry

Effect of Process Parameters on Material Removal Rate in Chemical Mechanical Polishing of 6H-SiC(0001)

2008 ◽  
Vol 600-603 ◽  
pp. 831-834 ◽  
Author(s):  
Joon Ho An ◽  
Gi Sub Lee ◽  
Won Jae Lee ◽  
Byoung Chul Shin ◽  
Jung Doo Seo ◽  
...  
Keyword(s):  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Colloidal Silica ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Diamond Particles ◽  
Average Grain Size ◽  
Silica Slurry ◽  
Sic Wafer

2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.

High Throughput SiC Wafer Polishing with Good Surface Morphology

2007 ◽  
Vol 556-557 ◽  
pp. 753-756 ◽  
Author(s):  
Tomohisa Kato ◽  
Keisuke Wada ◽  
Eiji Hozomi ◽  
Hiroyoshi Taniguchi ◽  
Tomonori Miura ◽  
...  
Keyword(s):  
Free Surface ◽  
High Throughput ◽  
Chemical Mechanical Polishing ◽  
Colloidal Silica ◽  
Flat Surface ◽  
Good Surface ◽  
Wafer Polishing ◽  
Silica Slurry ◽  
Sic Wafer ◽  
Afm Observation

We report SiC wafer polishing study to achieve high throughput with extremely flat, smooth and damageless surface. The polishing consists of three process, wafer grinding, lapping and chemical mechanical polishing (CMP), which are completed in shortest about 200 minutes in total for 2 inch wafer. Specimens of 4H- and 6H-SiC were provided from slicing single crystal as wafers oriented (0001) with 0 or 8 degrees offset angle toward to <112 _ 0>. By the first grinding using a diamond whetstone wheel, we realized flat surface on the wafers with small TTV error of 1 μm in 15 minutes. After second process of lapping, the wafers were finished by CMP using colloidal silica slurry. AFM observation showed not only scratch-free surface but also atomic steps on the wafers after CMP. Rms marks extremely flat value of 0.08 nm in 10 μm square area.

Experimental Study on Parameter Optimization of Silicon Wafer CMP Using Composite Abrasives Slurry

2009 ◽  
Vol 69-70 ◽  
pp. 214-218
Author(s):  
Xue Feng Xu ◽  
H.T. Ma ◽  
B.X. Ma ◽  
Wei Peng
Keyword(s):  
Silicon Wafer ◽  
Material Removal Rate ◽  
Material Removal ◽  
Colloidal Silica ◽  
Rotation Speed ◽  
Removal Rate ◽  
Polymer Particle ◽  
Optimal Parameters ◽  
Polymer Particles ◽  
Mechanism Of Interaction

In order to increase the material removal rate of silicon wafer, composite abrasives slurry was used in CMP. The mechanism of interaction between silica abrasives and polymer particles was analyzed. Small silica abrasives were seen to attach onto the surface of the polymer particles. Composite abrasives slurry was obtained by adding polymer particles into single abrasive slurry. Three key parameters, the concentration of colloidal silica, the concentration of polymer particle and the speed of polishing, which influence the material removal rate of silicon wafer were analyzed by Taguchi method and the optimal parameters were obtained. Experimental results indicated that the maximum material removed rate of 353nm/min was obtained when optimal craft parameters of 5% colloidal silica, 3% polymer particle, 50rpm plate and carrier rotation speed were selected.

The Mechanism of Polymer Particles in Silicon Wafer CMP

2009 ◽  
Vol 626-627 ◽  
pp. 231-236 ◽  
Author(s):  
Xue Feng Xu ◽  
H.F. Chen ◽  
H.T. Ma ◽  
B.X. Ma ◽  
Wei Peng
Keyword(s):  
Silicon Wafer ◽  
Material Removal Rate ◽  
Material Removal ◽  
Colloidal Silica ◽  
Removal Rate ◽  
Polymer Particle ◽  
Silica Shell ◽  
Polymer Particles ◽  
Interaction Potential Energy ◽  
Maximum Material Removal Rate

In order to increase the material removal rate of silicon wafer, composite abrasives slurry was used in CMP. Zeta potential of polymer particle was measured and interaction potential energy between silica abrasives and polymer particles in slurry were analyzed and calculated. Adsorptions between silica abrasives and polymer particles were observed with TEM. CMP experiments had been taken to analyze the effects of polishing parameters (the concentration of colloidal silica and polymer particle, the pressure and the speed of polishing) on the material removal rate. The mechanism of polymer particle in polishing was elaborated. Experimental results indicated that PS, PMMA and BGF polymer particles could adsorb silica abrasives in slurry. Silica shell/PS core, silica shell/PMMA core and silica shell/BGF core particles could be used to formulate composite abrasives slurries. The material removal rate with composite abrasives slurry was higher than that of single abrasive slurry. The maximum material removal rate was obtained with silica shell/BGF core composite abrasives slurry.

Acid colloidal silica slurry for Cu CMP

2004 ◽  
Vol 40 (1) ◽  
pp. 26
Author(s):  
Nam-Hoon Kim ◽  
Eui-Goo Chang
Keyword(s):  
Colloidal Silica ◽  
Silica Slurry ◽  
Cu Cmp

Performance of Polishing Slurries containing Silica Particles grown by Sol-Gel Method

2000 ◽  
Vol 613 ◽  
Author(s):  
Sun Hyuk Bae ◽  
Jae-Hyun So ◽  
Seung-Man Yang ◽  
Do Hyun Kim
Keyword(s):  
Fumed Silica ◽  
Sol Gel ◽  
Particle Growth ◽  
Silica Particles ◽  
Gel Method ◽  
Sol Gel Method ◽  
Irregular Shapes ◽  
Wafer Polishing ◽  
Transmission Electron ◽  
Silica Slurry

ABSTRACTSilica slurry used as abrasives in wafer polishing process is made by dispersing silica particles in an alkali solution. Since commercially available colloidal or fumed silica particles need some modifications to be directly used as abrasive slurry due to their small sizes, irregular shapes or broad size distribution, we have prepared silica abrasives by particle growth of fumed silica or colloidal silica as seeds by sol-gel method. Silica slurries prepared by this step-wise growth from commercial seeds were tested using one-armed polisher for the comparison with commercial slurries and showed the performance comparable to commercial slurries. Microstructures of polishing slurries were investigated using transmission electron microscopy and ARES rheometer. From the result, stability of the slurry was found to be more important than the primary particle sizes for the polishing performance.

Evaluation of Silicon Wafer Polishing Pads — Rheological Behaviour of Polishing Pads and Improvement of Wafer Flatness

1991 ◽  
pp. 192-201
Author(s):  
Yamato Samitsu ◽  
Takahumi Yoshida ◽  
Nobuo Yasunaga ◽  
Takashi Ohmoto ◽  
Sadamu Horie
Keyword(s):  
Silicon Wafer ◽  
Rheological Behaviour ◽  
Wafer Polishing ◽  
Polishing Pads

Experimental Investigation on Wafer Polishing of Oxide and Copper Layers

2002 ◽  
Author(s):  
Jhy-Cherng Tsai
Keyword(s):  
Process Parameters ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Back Pressure ◽  
Copper Layer ◽  
Wafer Polishing ◽  
Critical Technology ◽  
And Performance ◽  
Polishing Pressure

Polishing, in particular chemical-mechanical polishing (CMP), is a critical technology for the planarization of wafers. This paper investigates, via experiments, and compares the performance of CMP process with different process parameters for wafers with silicon-dioxide (SiO2) layer and for wafers with copper (Cu) layer. Polishing pressure (P), speed (V), and back pressure (BP) are used as process parameters in this study. Different pads and slurries are also experimented for copper layer as its properties are different from that of conventional oxide layer. Material removal rate (RR) and non-uniformity (NU) are used as indices to measure the performance. Experimental data on oxide layers show RR increases as P and V increase but NU gets worse at the same time. This condition can be improved, for both oxide and copper layers, with suitable BP. Experiments on copper CMP using slurry with abrasives show that RR increases with higher P and V. While NU gets worse with higher P, it can be reduced as V increases using a soft pad. Better NU can be obtained using soft pad though RR is lower in this case. For abrasive-free polishing of copper layer, RR, though relatively lower compared to CMP with regular slurry, is unstable using hard pad despite that NU becomes better at higher P. NU of polished wafer is best at certain pressure but becomes worse at low pressure for hard pad and at high P for soft pad. It is also observed that NU of AFP can be improved with BP and softer pad. Soft pad gives better polishing quality and performance though RR is lower than that using slurry with abrasives.

A New Permanganate-Free Slurry for GaN-SiC CMP Applications

2020 ◽  
Vol 1004 ◽  
pp. 199-205
Author(s):  
Treliant Fang ◽  
Ping Chung Chen ◽  
Ming Hsun Lee
Keyword(s):  
Removal Rate ◽  
Waste Water Treatment ◽  
High Hardness ◽  
Wide Band ◽  
Sodium Chlorite ◽  
Toxic Heavy Metal ◽  
Wafer Polishing ◽  
Single Crystal Sic ◽  
Buffer Control ◽  
Ph Buffer

Single crystal SiC wafers are known to be extremely difficult to polish by conventional CMP slurries because of their high hardness and chemical resistance. Previously only those manganese-containing CMP slurries are capable of producing measurable and useful polishing rates with this versatile wide band-gap substrate. A new permanganate-free SiC polishing slurry containing a generic formula of MXO2 etchant, where M is an alkali metal, X is a halogen, O is oxygen is disclosed. When mixed with an abrasive powder in an aqueous slurry form, the tribochemical reactant that activates under pressure, etches SiC effectively, rendering an enhanced Material Removal Rate (MRR) when processing CMP SiC wafers. The MRR can sometimes go up to a few order of magnitudes, as compared to the abrasive slurry without these chemical etchants. The series of MXO2 compounds that can activate SiC polishing belong to the chemical family of halites. Sodium chlorite, NaClO2, the simplest and most available member of the halites family, is a good example. The accelerated polishing rates offer increased throughput of the slow SiC CMP process. The new slurry is particularly useful for non-oxide wafer polishing, which includes SiC, GaN and AlN wafers. An outstanding character of the new halite-based polishing formulation that is different from the current permanganate-based slurries is that the waste stream produced from the CMP process can be easily treated in the waste water treatment facilities because they do not contain toxic heavy metal ions such as manganese and permanganate in the polishing formulations. Continuous exhaustive CMP polishing test with 32 4” 4H-N SiC wafers using a production CMP tool containing 32L of the alumina-chlorite slurry has demonstrated an MRR of 1.7um/hr (Si-face) when the slurry is fresh, and a final MRR of 1.0um/hr after 16 hours polishing at 800mL/min slurry flow rate with pH buffer control without fresh oxidant addition. The resulting 32 polished 4H-SiC test wafers show overall excellent smooth surface roughness with the best Ra of 0.05nm by AFM after fine CMP polishing.

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