All-Wet Strip Approaches for Post-Etch Photoresist Layers After Low-K Patterning

Claes, Martine; Le, Quoctoan; Kesters, Els; Lux, Marcel; Urionabarrenetxea, Ariana; Vereecke, Guy; Mertens, P.; Carleer, Robert; Adriaensens, Peter

doi:10.1149/1.2779377

Cited by 19 publications

(13 citation statements)

References 9 publications

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“…One reason why the TD brushes stretched less laterally is because of the damage done by RIE to the chains at the very edge of the pattern. Another possibility is the cross-linking between the polymer chains, which could also happen because of RIE treatment. − Cross-linking could also explain why the 225 nm pattern relaxed incompletely in acetone. Although cross-linking was not obvious for PMMA brushes, it would later be more obvious for the patterned PMETAC brushes.…”

Section: Resultsmentioning

confidence: 99%

Reduced Lateral Confinement and Its Effect on Stability in Patterned Strong Polyelectrolyte Brushes

Chen¹,

Menzel

Watanabe

et al. 2017

Langmuir

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The stability of strong polyelectrolyte brushes (PEBs) was studied in bulk and in patterned structures. Thick PEBs of poly([(2-methacryloyloxy)ethyl]trimethylammonium chloride) with thicknesses >100 nm were synthesized using single electron transfer living radical polymerization. Brush patterning was identified using deep-ultraviolet photolithography by means of either a top-down (TD) or bottom-up (BU) method, with features as small as 200 nm. The brushes were soaked in water under a range of pH or temperature conditions, and the hydrolysis was monitored through dry-state ellipsometry and atomic force microscopy measurements. BU patterns showed reduced degrafting for smaller patterns, which was attributed to increased stress relaxation at such dimensions. In contrast to the already relaxed BU-patterned brush, a TD-patterned brush possesses perpendicular structures that result from the use of orthogonal lithography. It was found that the TD process induces cross-linking on the sidewall, which subsequently fortifies the sidewall materials. This modification of the polymer brushes hindered the stress relaxation of the patterns, and the degrafting trends became irrelevant to the pattern sizes. With proper tuning, the cross-linking on the sidewall was minimized and the degrafting trends were again relaxation-dependent.

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Section: Resultsmentioning

confidence: 99%

Reduced Lateral Confinement and Its Effect on Stability in Patterned Strong Polyelectrolyte Brushes

Chen¹,

Menzel

Watanabe

et al. 2017

Langmuir

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“…Because such phenomena were not observable for BU patterned brushes, it must be caused by the TD patterning process. A possible explanation for this behavior is that the plasma process induces cross-linking of the polymer at the edges of the pattern through formation of additional covalent bonds. − Such cross-linked fraction of the pattern show a rubber-like behavior; i.e., when they are deformed and the forces which cause them to deform are removed, they will return to their original shape. Thus, strong swelling of the system will cause the system to deform, and this deformation is “frozen in” by drying.…”

Section: Resultsmentioning

confidence: 99%

Morphology of Nanostructured Polymer Brushes Dependent on Production and Treatment

Chen¹,

Menzel

Prucker

et al. 2017

Macromolecules

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The morphology of top-down and bottom-up nanostructured neutral brushes is studied as a function of the production process and the quality of solvent to which the brushes have been exposed. Neutral brushes of poly(tert-butyl methacrylate) (PtBuMA) were grafted from the substrate by surface-initiated radical-chain polymerization (SI-RCP). Brush patterning was conducted using deep ultraviolet (DUV) photolithography following either top-down (TD) or bottom-up (BU) approaches with patterned lines as small as 200 nm. The resulting brushes were immersed in toluene or methanol, and the change of morphology of the dried brushes was monitored using tapping mode atomic force microscopy (AFM). TD nanopatterned brushes (NPBs) exhibit a box-like and BU generated brushes a lens-like shape directly after the production process. We show that the pattern width for the BU brushed depends not only on the wetting properties of the areas adjacent to the pattern but also on the process history to which the sample has been exposed, especially the solvent quality. Furthermore, we show that TD NPBs are cross-linked on the edges of the pattern because of the high-energy process conditions during brush patterning and study the behavior of the thus-obtained structures.

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“…1 2 pitch ≤ 90 nm. 6 In previous studies, we have shown that the degradation of 193 nm DUV PR by etch plasma extended much deeper than ion penetration depth and that bulk mod-ifications were comparable to the degradation of PMMA under low energy radiation such as UV. 23,24 The role of plasma Vacuum Ulta Violet (VUV) in deep modifications was confirmed by several dedicated studies.…”

mentioning

confidence: 88%

“…[1][2][3][4] To minimize damage to low-k material, wet alternative methods for removal of PR layer are gaining a renewed interest. [5][6][7][8] Relying on a long tradition of development of solvent based strippers, chemical companies developed a new generation of organic wet strippers targeting the new challenges. [9][10][11][12][13][14] The most widely-used commercially available organic strippers used to be the phenol-based ones, but their short pot life and difficulties with phenol disposal made phenol free strippers, e.g.…”

mentioning

confidence: 99%

Towards Fully Aqueous Ozone Wet Strip of 193 nm Photoresist Stack Using UV Pre-Treatments in Low-kPatterning Applications

Kesters

Lux

et al. 2012

J. Electrochem. Soc.

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All-wet processes are gaining a renewed interest for the removal of post-etch photoresist (PR) and Bottom Anti Reflective Coating (BARC) in the Back-End-Of-Line (BEOL) semiconductor manufacturing, as an alternative to plasma strip, which may cause damage to advanced porous low-k materials. However, degradation of DUV PR by etch plasmas results in a modified top layer that is cross-linked (so-called crust) and therefore not soluble anymore using pure organic solvents. This study investigates the combination of UV with ozonated processes to remove PR and BARC in BEOL applications. Treatment of PR and BARC by UV irradiation was proved to be an interesting process to increase the concentration of reactive C=C bonds in the post-etch PR and BARC layer. Another effect of UV irradiation is that it can cause scissioning of C-C bonds in the PR main chain, thereby improving the dissolution of the PR in solvents. This UV pre-treatment was used as a preliminary step to enhance PR and BARC removal by ozonated wet strips. Different pathways were studied in detail, leading to the development of a fully aqueous ozonated wet strip process.

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All-Wet Strip Approaches for Post-Etch Photoresist Layers After Low-K Patterning

Cited by 19 publications

References 9 publications

Reduced Lateral Confinement and Its Effect on Stability in Patterned Strong Polyelectrolyte Brushes

Reduced Lateral Confinement and Its Effect on Stability in Patterned Strong Polyelectrolyte Brushes

Morphology of Nanostructured Polymer Brushes Dependent on Production and Treatment

Towards Fully Aqueous Ozone Wet Strip of 193 nm Photoresist Stack Using UV Pre-Treatments in Low-kPatterning Applications

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