Atomic force microscopy infrared spectroscopy (AFM-IR) uses photothermal expansion to transduce local infrared absorption at < 10 nm spatial resolution. Due to its ease of use and its ability to directly yield infrared absorption spectra without the need for modeling this technique has been applied to life science (sub-cellular imaging, single protein spectroscopy), material science (polymers, interfaces) and photonics (modal shapes in 2D materials) and other fields. While some tentative first steps in AFM-IR in liquid have been made in recent years and even though liquid AFM-IR promises nanoscale resolution chemical analysis of solid-liquid reactions and imaging of life microorganisms, is still far from routine use or wide adoption. In this work we address one of the more pressing technical issues that currently preclude wider use of liquid phase AFM-IR: the costly and unwieldy ZnSe prism sample carriers required for attenuated total reflection bottom illumination geometries. We show how they can be replaced by micro-machined Si wafers. These wafers are more flexible, chemically robust and cost effective then conventional sample carrier prisms. Through optical simulations (transfer matrix method, ray optics and finite difference time domain) we show that the micromachined wafers provide a depth of penetration comparable to that of conventional ZnSe prisms, exhibit small change in focal position during scanning and no optical hot spots or interference that might be detrimental to reproducible AFM-IR measurements. We demonstrate the use of these carriers in air and water experimentally.