Pattern collapse has long been known in photoresist patterning where the resist patterns merge or collapse during rinsing and drying steps [. The forces responsible for this collapse were identified as capillary forces during the drying process. Structures such as titanium nitride DRAM cylinders [ and silicon Flash shallow trench isolation (STI) lines have also been observed to be pattern collapse sensitive due to increase in aspect ratio of the features. Micro-electromechanical systems (MEMS) devices also show a similar phenomenon, but on a larger length scale, and is referred to as stiction [. For the technology nodes <14 nm, back-end-of-line (BEOL) low-k structures are also on the verge to show pattern collapse behavior. Whether a structure is sensitive to pattern collapse or not depends on several parameters, which will be analyzed in this paper.

High dosed ion implanted (HDI) photoresist is well-known to be difficult to remove by conventional wet stripping e.g. sulfuric–peroxide mixture without substrate loss because of their carbonized crust layer. To overcome this issue, several methods are proposed such as dry etch + wet, assist of physical cleaning. In this paper, a new method to strip HDI photoresist using a combination of dry and wet processing in the same chamber is introduced to achieve HDI photoresist removal without substrate loss. A new process consists of two steps. The first process removes the carbonized crust layer by atmospheric-pressure inductively coupled hydrogen plasma, and the second process removes remaining the bulk photoresist by a sulfuric–ozone mixture. The new process enables removal of the HDI photoresist without any substrate loss, and with significantly shorter times.

The effect of standard aqueous cleans including SC-1, HCl, HF, and HCl/HF mixtures on SiGe(100) surfaces with 50, 75 and 85% Ge molar ratios was characterized with x-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry. HF was most effective at removing both Ge and Si oxides and reduced the carbon contamination. SC-1 selectively depleted Ge from the surface. Passivation of Ge(100) surfaces with aqueous (NH4)2S was characterized with XPS as a function of the solution concentration and with the addition of H2O2. The passivation process was independent of the (NH4)2S concentration and approximately 3 Å of S was deposited or about one layer based on XPS. Addition of H2O2 to very dilute (NH4)2S oxidized the surface while addition to higher concentrations showed similar effects as a sequential HCl/H2O2 treatment.

Residual particles significantly degrade the performance of large-scale integrated circuits; hence, the methods and efficiencies of particle-removal technologies for semiconductor wafer-cleaning processes are continuously being improved. This paper reports a deionized water (DIW)-based approach that significantly improves the particle removal efficiency (PRE) of polystyrene latex (PSL) particles from oxide surfaces. PSL particles are generally very difficult to remove from silicon oxide surfaces using DIW alone. We previously attempted to improve the PSL removal rate with DIW by increasing the wafer rotation speed and the medium flow rate in single-wafer spin processing. However, the maximum PRE was below 50% (PSL, 500 nm spheres). This study reports on the improvement of the PRE to >98.0% by combining a DIW clean with a very low wafer rotation speed (10 rpm) and a very low DIW flow rate (200 ml/min). The spatial distribution of the PRE matches that of the calculated capillary numbers across the wafer. We propose that the low wafer rotation speed and DIW flow rate impact the capillary number, allowing the DIW to percolate between the PSL particles and the oxide surface. Particles uplifted by this process become suspended in or on top of the liquid layer covering the wafer, and are removed when the rotation speed of the wafer is increased during the final drying process.

Tristrimethylsilylgermane, (Me3Si)3GeH, was employed as a molecular model compound for hydrogen terminated Ge(111) surfaces. Time and temperature dependent NMR spectroscopy yielded rate constants for the reaction between (Me3Si)3GeH and elemental sulfur and allowed for the determination of the activation energy for this molecular model reaction to mimic germanium surface passivation.