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front-end.md [2026/07/02 15:54] – [Processes] eric.fourboul.extfront-end.md [2026/07/09 21:05] (current) – [Processes] eric.fourboul.ext
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   * The polishing pad. This is the mechanical pad that rubs against the surface of the wafer.   * The polishing pad. This is the mechanical pad that rubs against the surface of the wafer.
   * The slurry. This is a liquid mixture that generally contains:    * The slurry. This is a liquid mixture that generally contains: 
-  *   * water;  +       - water;  
-  *   * abrasive particles (silica, alumina, ceria, depending on the process); +       - abrasive particles (silica, alumina, ceria, depending on the process); 
-  *   * chemical agents to oxidise, complex or selectively etch the material; +       - chemical agents to oxidise, complex or adjust pH; 
 There are three primary types  of CMP: oxide CMP, tungsten CMP, and copper CMP There are three primary types  of CMP: oxide CMP, tungsten CMP, and copper CMP
  
 #### 9.1. Oxide CMP #### 9.1. Oxide CMP
-Oxide CMP defines the electrical isolation geometry between every transistor on a chip.+Oxide CMP is primarily used to flatten dielectric layers. 
 +It is used to: 
 +  * flatten an interlayer dielectric (ILD); 
 +  * STI (Shallow Trench Isolation): after filling the isolation trenches; 
 +  * restoring the surface to a flat state before a new lithography or metallisation step; 
 +  * reducing the topography created by the previous steps. 
 ##### Inputs ##### Inputs
-* Silica (SiO2) 
-Derived from TEOS (tetraethyl orthosilicate): Si(OCH₂CH₃)₄ or Si(OEt)₄ TEOS forms SiO₂ through simple hydrolysis, releasing ethanol (CH₃CH₂OH) : 
-Si(OCH2CH3)4 + 2 H2O → SiO2 + 4 CH3CH2OH 
  
-* Ceria (CeO₂) +  * Silica (SiO2) as abrasive 
-Ceria slurries achieve much higher oxide removal rates and superior planarization efficiency, making them preferred for "Shallow Trench Isolation" (STI), i.e. the technique that electrically isolates adjacent transistors. + Derived from TEOS (tetraethyl orthosilicate): Si(OCH₂CH₃)₄ or Si(OEt)₄ TEOS forms SiO₂ through simple hydrolysis, releasing ethanol (CH₃CH₂OH) : 
 +Si(OCH2CH3)4 + 2 H2O → SiO2 + 4 CH3CH2OH  
 + 
 +  * Ceria (CeO₂) 
 +Ceria slurries achieve much higher oxide removal rates and superior planarization efficiency, making them preferred for "Shallow Trench Isolation" (STI), i.e. the technique that electrically isolates adjacent transistors.  
  
-##### Outputs+  * hydroxide ions (OH⁻) 
 +  * Amoniac (NH3) as pH adjustor 
 +  * Potassium hydroxyde (KOH) as pH adjustor 
  
 +##### Outputs
 +  * Silicon Nitride Si₃N₄
 +  * poly-Si
  
  
 #### 9.2. Tungsten CMP #### 9.2. Tungsten CMP
 +Tungsten CMP is used to remove excess tungsten after it has filled openings.
 +It is used to:
 +  * form contacts;
 +  * form tungsten-filled vias;
 +  * remove tungsten deposited everywhere except in the required cavities.
 The most widely used approach uses ferric nitrate (Fe(NO₃)₃) or hydrogen peroxide (H₂O₂) as the oxidising agent to convert the tungsten surface to a soft tungsten oxide (WO₃) layer, which is then mechanically removed by the abrasive.  The most widely used approach uses ferric nitrate (Fe(NO₃)₃) or hydrogen peroxide (H₂O₂) as the oxidising agent to convert the tungsten surface to a soft tungsten oxide (WO₃) layer, which is then mechanically removed by the abrasive. 
 ##### Inputs ##### Inputs
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   * ferric nitrate (Fe(NO₃)₃)    * ferric nitrate (Fe(NO₃)₃) 
   * hydrogen peroxide (H₂O₂)    * hydrogen peroxide (H₂O₂) 
 +  * Titanium nitride (TiN)
 +  * Silica (SiO2)
  
 ##### Outputs ##### Outputs
-* tungsten oxide (WO₃)+  * tungsten oxide (WO₃)
  
 ##### Formula ##### Formula
-* 2W + 3H₂O₂ → WO₃ + 3H₂O (oxidation)+  * 2W + 3H₂O₂ → WO₃ + 3H₂O (oxidation)
 followed by: followed by:
-* WO₃ + abrasive contact → material removal+  * WO₃ + abrasive contact → material removal
  
 #### 9.3. Copper CMP #### 9.3. Copper CMP
 +Copper CMP is used to form copper interconnections, particularly in Damascene or dual-layer schemes 
 +It is used to: 
 +  * remove excess copper deposited on the surface; 
 +  * leave copper only in the trenches and vias intended for interconnect lines; 
 +  * planarise after metallisation. 
 +The most specific feature of copper CMP slurry is the use of benzotriazole (BTA) as a corrosion inhibitor. 
 ##### Inputs ##### Inputs
-hydrogen peroxide (H₂O₂)  +  *  5-Methyl-1H-benzotriazole (C7H7N3) 
- +  * Copper (Cu) 
- +  * Silica (SiO2) as abrasive 
-#### 9.1. Planarization +  * hydrogen peroxide (H₂O₂)  
-  * Silicon dioxide (SiO2) +  * Tantalum nitride (TaN) 
-  * Aluminium oxide (Al2O3) +  * Tantalum (Ta) 
-  * Cerium oxide (CeO2) +  * Amoniac (NH3) as pH adjustor 
-  * Deionized water (DI Water) +  * Sodium hydroxyde (NaOH) as pH adjustor 
-  * Hydrofluoric acid (HF) +d
-  * Sulfuric acid (H2SO4) +
-  * Sodium hydroxide (NaOH) +
-  * Potassium hydroxide (KOH) +
-  * Ammonium hydroxide(NH4OH) +
- +
-##### Inputs +
- +
-  * test +
-  * test +
- +
- +
-##### Outputs +
- +
-  * test +
-  * test +
- +
- +
-##### Formula +
- +
-to add +
 ### Manufacturers ### Manufacturers
   * [Applied Materials](https://www.appliedmaterials.com/eu/en/product-library.html)   * [Applied Materials](https://www.appliedmaterials.com/eu/en/product-library.html)
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   * Chemical Mechanical Planarization, [CMP Process Fundamentals: CMP Tools and Process](https://www.youtube.com/watch?v=2z4lq-Ms_OU) ; [CMP Process Fundamentals: CMP Slurries](https://www.youtube.com/watch?v=lWvvKGkFDfk)   * Chemical Mechanical Planarization, [CMP Process Fundamentals: CMP Tools and Process](https://www.youtube.com/watch?v=2z4lq-Ms_OU) ; [CMP Process Fundamentals: CMP Slurries](https://www.youtube.com/watch?v=lWvvKGkFDfk)
   * [jeez-semicon](https://jeez-semicon.com/fr/blog/copper-cmp-vs-tungsten-cmp-vs-oxide-cmp-full-comparison/)   * [jeez-semicon](https://jeez-semicon.com/fr/blog/copper-cmp-vs-tungsten-cmp-vs-oxide-cmp-full-comparison/)
- 
 ### Sources ### Sources
   * Zantye, P. B., Kumar, A., & Sikder, A. K. (2004). Chemical mechanical planarization for microelectronics applications. Materials Science and Engineering: R: Reports, 45(3-6), 89-220.   * Zantye, P. B., Kumar, A., & Sikder, A. K. (2004). Chemical mechanical planarization for microelectronics applications. Materials Science and Engineering: R: Reports, 45(3-6), 89-220.
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   * Kim, H. J. (2018). Abrasive for chemical mechanical polishing (pp. 183-201). Rijeka: InTech   * Kim, H. J. (2018). Abrasive for chemical mechanical polishing (pp. 183-201). Rijeka: InTech
   * Lee, J., He, S., Song, G., & Hogan Jr, C. J. (2022). Size distribution monitoring for chemical mechanical polishing slurries: An intercomparison of electron microscopy, dynamic light scattering, and differential mobility analysis. Powder Technology, 396, 395-405.   * Lee, J., He, S., Song, G., & Hogan Jr, C. J. (2022). Size distribution monitoring for chemical mechanical polishing slurries: An intercomparison of electron microscopy, dynamic light scattering, and differential mobility analysis. Powder Technology, 396, 395-405.
 +  * XU, Qinzhi, CHEN, Lan, YANG, Fei, et al. Influence of slurry components on copper CMP performance in alkaline slurry. Microelectronic Engineering, 2017, vol. 183, p. 1-11.
 +  * PARK, Seonghyun et LEE, Hyunseop. Electrolytically ionized abrasive-free CMP (EAF-CMP) for copper. Applied Sciences, 2021, vol. 11, no 16, p. 7232.
  
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