Slurry for chemical mechanical polishing
Chemical mechanical polishing of copper wiring layers in semiconductor devices by using a slurry containing abrasives, oxidants, organic acids, and branched polyolefin-polyalkylene oxide copolymers in the CMP method, resolving dishing and over-polishing problem, achieving efficient polishing selectivity and improved electrical performance.
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Embodiment 1 to 9
[0068] Examples 1 to 9: Preparation of slurry for CMP
[0069] As shown in Table 1 below, a slurry for CMP was prepared, the slurry including an abrasive; an oxidizing agent; an organic acid; and a polymer additive containing a polyolefin-polyalkylene oxide copolymer, The polyolefin-polyalkylene oxide copolymer includes two or more polyalkylene oxide repeating units, and at least one polyalkylene oxide repeating unit is branched.
[0070] The following materials were used as the components of the CMP slurry prepared in the examples.
[0071] Use AB3-1, AB3-2, AB3-3, AB3-4 and AB3-5 (Mitsui Co.) as polyolefin-polyalkylene oxide copolymers, in which 3 polyalkylene oxide repeating units (Mn is 200- 2,000) and polyolefin (Mn is 500-1500) are copolymerized, as shown in the above chemical formula 2. In addition, AB2 (Mitsui Co.) is selectively used as a polyolefin-polyalkylene oxide copolymer, in which polyolefin (Mn is 500-1500) and 2 polyalkylene oxide repeating units (Mn is 200-2000) ...
experiment example 1
[0086] Experimental example 1: Measurement of etching rate
[0087] Cut the wafer with a 1500nm copper layer deposited on it by EP (electroplating) into 2×2cm 2 Then, the wafer slices were immersed in each slurry (30ml) of the embodiment and the comparative example for 30 minutes. The weight change of the wafer before and after immersion is converted into the etching amount of copper, so as to calculate the etching rate of the slurry to the copper layer ( / Min), and the results are shown in Tables 3 and 4 below.
[0088] After measuring the etching rate, the wafers of the Examples and Comparative Examples were subjected to AFM analysis. The results are shown in Tables 3 and 4 below. For the surface condition of copper, ◎ means very good (Cu surface roughness is less than 10 ), ○ means good (Cu surface roughness is 10 Or greater but less than 20 ), △ represents general (Cu surface roughness is 20 Or greater but less than 40 ), × represents difference (Cu surface roughness is 4...
experiment example 2
[0089] Experimental example 2: Measurement of polishing rate
[0090] The CMP slurry of the embodiment and the comparative example was used to polish the wafer for 1 minute. After that, measure the thickness of the copper layer, tantalum layer and silicon dioxide layer before and after polishing, and then calculate the polishing rate of the slurry on the copper layer, tantalum layer and silicon dioxide layer from the measured thickness (polishing rate: / minute). In addition, the polishing selectivity of the slurry between the copper layer and other layers is calculated from the polishing rate of each layer (the polishing selectivity of the copper layer relative to the tantalum layer or the polishing selectivity of the copper layer relative to the silicon dioxide layer) . The polishing rate and polishing selectivity for each layer are shown in Tables 3 and 4.
[0091] [Polishing conditions]
[0092] Polishing device: POLI-500 (GnP Co.)
[0093] Polishing pad: IC1000 / SubaIV Stacked ...
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Abstract
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