Quantum interferometric optical lithography uses entangled photons to surpass the diffraction limit in writing features on a substrate. Classical lithography is limited to writing features of size λ/2 or larger, where λ is the optical wavelength. However, using entangled photon states, it is possible to write features as small as λ/(2N), where N is the number of photons. This allows for a factor of N² more elements to be written on a semiconductor chip. For N=2, this can be achieved using entangled photon pairs generated by optical parametric downconversion. The method enables the writing of arbitrary 2D patterns by using entangled photon states. The paper demonstrates that entangled photon states can achieve sub-diffraction-limited resolution. By using entangled photon number states, the resolution can be improved beyond the classical Rayleigh limit. The quantum interference of entangled photons allows for the elimination of certain terms in the exposure dosage, leading to a higher resolution. For example, using a two-photon entangled state, the resolution can be improved to λ/4, which is a factor of two better than classical methods. The paper also discusses the generation of entangled photon number states. For N=2, this can be achieved using a parametric down-conversion event followed by a symmetric beamsplitter. For higher N, nonlinear materials or cascaded crystals can be used. The entangled states can be used to create patterns with higher resolution. The paper shows that entangled N-photon absorption can achieve a resolution of λ/(2N), which is a factor of N below the classical Rayleigh limit. The paper concludes that entangled photon states can be used to overcome the diffraction limit in lithography. This technique has the potential to significantly improve the resolution and efficiency of semiconductor manufacturing. The method is applicable for writing arbitrary 2D patterns, and the use of entangled photons provides a powerful resource for overcoming the diffraction limit in optical lithography.Quantum interferometric optical lithography uses entangled photons to surpass the diffraction limit in writing features on a substrate. Classical lithography is limited to writing features of size λ/2 or larger, where λ is the optical wavelength. However, using entangled photon states, it is possible to write features as small as λ/(2N), where N is the number of photons. This allows for a factor of N² more elements to be written on a semiconductor chip. For N=2, this can be achieved using entangled photon pairs generated by optical parametric downconversion. The method enables the writing of arbitrary 2D patterns by using entangled photon states. The paper demonstrates that entangled photon states can achieve sub-diffraction-limited resolution. By using entangled photon number states, the resolution can be improved beyond the classical Rayleigh limit. The quantum interference of entangled photons allows for the elimination of certain terms in the exposure dosage, leading to a higher resolution. For example, using a two-photon entangled state, the resolution can be improved to λ/4, which is a factor of two better than classical methods. The paper also discusses the generation of entangled photon number states. For N=2, this can be achieved using a parametric down-conversion event followed by a symmetric beamsplitter. For higher N, nonlinear materials or cascaded crystals can be used. The entangled states can be used to create patterns with higher resolution. The paper shows that entangled N-photon absorption can achieve a resolution of λ/(2N), which is a factor of N below the classical Rayleigh limit. The paper concludes that entangled photon states can be used to overcome the diffraction limit in lithography. This technique has the potential to significantly improve the resolution and efficiency of semiconductor manufacturing. The method is applicable for writing arbitrary 2D patterns, and the use of entangled photons provides a powerful resource for overcoming the diffraction limit in optical lithography.