PPS Retaining ring TECATRON CMP natural

CMP retaining rings

An especially crucial step in silicon wafer processing for integrated circuit manufacturing is the Chemical Mechanical Planarization (CMP) process. The retaining ring is an integral part of the CMP process and functions to hold the wafer under the carrier during polishing, to secure it from slipping out of the carrier head, and to achieve uniform material removal. Materials used for CMP retainer rings need to maintain dimensional stability over a wide range of temperatures and pressures and withstand harsh chemicals in CMP slurries. The challenge is to find a retaining ring material with a combination of material properties, which would improve the CMP process's efficiency and keep wafer-level defects to a minimum.  

In close cooperation with customers, we have specialised in developing materials that are frequently used in interlayer dielectric, shallow trench isolation, copper interconnects, tungsten plugs, and other CMP applications. With several decades of experience in offering materials for CMP retaining rings, Ensinger can provide solutions for addressing the following challenges: 

  • As with all Ensinger semiconductor grades, the CMP tubes grades are manufactured in compliance with semiconductor Copy Exact requirements and more stringent quality controls compared to industrial grades. Ensinger's Copy Exact management includes lockdown of raw material supplier, raw material type, and production facility. As even minor differences of the material property have an impact on the overall CMP process performance, copy exact compliance down to the raw material is key for maintaining high level performance consistency.
    Value chain from Raw material to machined clamp ring
  • A substantial proportion of the overall retaining ring cost consists of the ring material cost. Choosing the best fitting plastic tube size for the machined retaining ring enables less machined waste and effort, significantly impacting the material cost. For example, changing from industry-standard size OD360/ID290 mm with 58,3 kg/m to the smaller size OD350/ID300 mm of TECAPEEK CMP with 42,2 kg/m results in up to 27 % material waste and cost savings. With almost 4000 different combinations of polymers and tube dimensions, Ensinger offers the best tube size product portfolio in the industry. 

    With our PPS material TECATRON SX natural and PEEK material TECAPEEK SX natural Ensinger offers a wide range of tube dimensions for the semiconductor industries demands. In addition to a wide range of tube sizes in stock, custom order dimensions are available on request.

    Wafer size

    06" (150 mm)

    08" (200 mm)


    12" (300 mm)

    Dimensions (OD / ID)

       180 / 125  230 / 150  280 / 210  340 / 260

     180 / 130  230 / 180  285 / 180  
     340 / 310
       180 / 140  230 / 190  285 / 190    350 / 300
       180 / 150  230 / 195  285 / 195    360 / 290
       180 / 160  230 / 200  285 / 200    360 / 295
       185 / 125  238 / 210  285 / 210 
     364 / 260
       185 / 130  250 / 180  285 / 220 

     185 / 140  250 / 190  300 / 180   
       185 / 150  250 / 195
     300 / 190  

     185 / 160
     250 / 200  300 / 195    

     190 / 125  250 / 210  300 / 200    
       190 / 130  250 / 220  300 / 210  
       190 / 140  255 / 180  300 / 220  
       190 / 150  255 / 190  305 / 180  
       190 / 160  255 / 195  305 / 190  
       200 / 125  255 / 210  305 / 195  
       200 / 130  255 / 220  305 / 200  

     200 / 140
     277 / 180  305 / 210  
     200 / 150  277 / 190  305 / 220  
       200 / 160  277 / 195    
       200 / 175  277 / 200    
       210 / 125  277 / 210    
       210 / 130  277 / 220    
       210 / 140  280 / 180    
       210 / 150  280 / 200    
    Please contact us for sizes not mentioned in the above overview. We will check for customer specific settings in order to get as close as possible to the final part size.
  • The retaining ring material is the main factor influencing the ring wear rate. Lower wear resistance leads to frequent changing of the rings and thus contributes to a reduced tool utilization and increased cost of ownership. Generally, PEEK offers up to three times better wear resistance than PPS, significantly extending ring lifetime. Further, PEEK CMP offers up to 20 % better wear resistance than standard industry PEEK. 
    PPS, TECATRON, Bühler-test, oxide slurry
  • Minor differences in the material properties of the CMP retaining ring can alter the micro-texture of the pad, cause different amounts of pad fragments and shavings, and result in different shapes of pad asperities. For example, compared to using competitor PPS, Ensinger's TECATRON CMP shape wears the pads in a manner so that the pad asperities are optimised for enhanced material removal as well as reduced defects. Reducing the level of defective dies and improving yield has significant impact on the cost of ownership.
    More information: Case Study CMP Retaining Ring
    Retaining ring pad surface
  • Other sources of micro-scratches are inner ring groove wear (also known as side attacks), causing uneven inner ring walls and inducing slurry and other particles to adhere to the wall, agglomerate, later dislodge, and scratch the wafer. Inner groove wear is not much of an issue with PPS or PC as the material wears on the face of the ring at a rate so the inner groove is always seeing new material. However, high performance materials like PEEK provide strong wear resistance on the face of the ring so that inner groove wear can occur and cause excessive defects. The property profile of the ring material, in particular the balance of ductility and hardness, has an impact on the inner groove wear behaviour. Ensinger has developed the shape TECAPEEK CMP with an optimised property profile that enables reduced inner groove wearing compared to standard PEEK.  
    Another influencing factor for causing inner groove wearing is the distortion of ring roundness. Deformation while wearing can result by the release of residual stress in the material which is induced by the molding process. All Ensinger CMP materials are produced via extrusion, minimizing residual stress levels, and enhancing crystallinity, enabling higher dimensional stability than other processing methods such as injection molding.  
  • Consistent flatness and fewer ring thickness deviations are vital for minimizing pad deformation and rebounding, which causes irregular material removal and over-polishing at the wafer edges. Better uniformity of the material removal rate (MRR) enables lower within-wafer nonuniformity (WIWNU) and has a significant impact on yield. Generally, a lower residual stress level in the material of the retaining ring enables better retaining ring flatness and contact angle. Ensinger's tube materials for CMP retaining rings are manufactured using extrusion technology, which is a slow and continuous process enabling lower residual stress levels than other manufacturing methods such as injection molding. Extruded rings enable more consistent property profile than injection molded rings as there is no weld line, which also contributes to better dimensional stability.  
  • Ion impurities of the polymer or the additives can leach out and cause contaminations. All Ensinger CMP material grades use pure polymers, avoiding the risk of contamination. Besides the purity of the base material, impurities can also be molded-in during the manufacturing of the material. In general, the extrusion process enables better control of product and quality consistency than injection molding, lowering risks of contamination. Additionally, all Ensinger CMP material grades undergo more thorough quality controls than general-purpose grades, resulting in higher safety from foreign particles. 
    Aluminium (Ai) < 1 < 1 < 1 < 1
    Calcium (Ca) < 4 < 10 < 10 n.t.
    Copper (Cu) < 1 < 1 < 1 n.t.
    Iron (Fe) < 2 < 4 < 3 < 1
    Magnesium (Mg) < 1 < 6 < 1 < 1
    Potassium (K) < 1 < 1 < 1 < 1
     Zinc (Zn) < 1 < 1 < 1 n.t


    Test in accordance with ICP-MS, concentration levels stated in ppm; (n.t.= not tested)
  • Ensinger runs efficient stock management and global demand planning systems to ensure that we provide the best availability and delivery performance of CMP tube materials in the industry. Warehouses all around the world are extensively stocking our CMP materials. Moreover, close partnership and supply assurances with premier raw material suppliers enable Ensinger to minimize risks of delivery bottlenecks. 
    Ensinger Nufringen stock shapes warehouse

Product Portfolio

TECADUR PET CMP natural Teaser

Case studies & Applications

Retaining ring

CMP Retaining Ring


How to meet the numerous requirements of CMP process

The retaining ring is a crucial component of the CMP process, as it holds the wafer under the carrier during polishing and facilitates uniform material removal. Selecting the right ring material is critical as it affects the efficiency of the CMP process and the level of wafer-level defects. This experimental study demonstrates how TECATRON CMP natural can reduce the number of defective dies and improve yield.
CMP retaining ring made from TECAPEEK

CMP Retaining Ring machined from TECAPEEK CMP natural tube

  • Excellent wear resistance and strength
  • Special property profile enabling less side attacks
  • High ionic purity
  • Good dimensional stability
  • Copy exact compliant
CMP rint made from TECADUR PET CMP

CMP Retaining Ring machined from TECADUR PET CMP natural tube


  • Good wear resistance at moderate temperatures
  • Low coefficient of friction
  • Resistant to hydrolysis up to +70°C
  • Good dimensional stability
  • Copy exact compliant
Retaining ring TECANAT CMP

Wafer Lapping Retaining Ring machined from TECANAT CMP natural tube

  • Cost efficient 
  • Good machinability
  • Good dimensional stability
  • Good impact resistance
  • Copy exact compliant


To request material samples or ask for a quotation please navigate through the product detail pages. If you are not sure what materials to use for your application, or if you have questions on technical details feel free to contact our technical support for advice.