Safe separation for nano imprinting
View Patent ↗Control of lateral strain and lateral strain ratio (d t /d b ) between template and substrate through the selection of template and/or substrate thicknesses (T t and/or T b ), control of template and/or substrate back pressure (P t and/or P b ), and/or selection of material stiffness are described.
1. An imprint lithography method for separating an imprint lithography template from a patterned layer formed by contacting the imprint lithography template with a formable material disposed on a substrate and solidifying the formable material to form the patterned layer such that the template features and the substrate features have lateral strains d t and d b associated therewith, respectively, when subjected to a separation force, the method comprising:
determining a difference between the lateral strains d t and d b by measuring the lateral strain values during an initial separation or modeling the lateral strain values during a theoretical separation;
based on the determined difference between the lateral strains d t and d b , determining a back pressure P t to apply to the template, a back pressure P b to apply to the substrate, or both such that a ratio of lateral strains d t /d b is approximately 1 when the template and the substrate are subjected to the separation force;
applying the determined back pressure P t to the template, the determined back pressure P b to the substrate, or both while at least a portion of the template is in contact with the patterned layer on the substrate; and
applying the separation force to separate the template from the patterned layer on the substrate.
2. The method of claim 1 , wherein the back pressure P b applied to the substrate exceeds the back pressure P t applied to the template.
3. The method of claim 1 , wherein applying the determined back pressure P t to the template comprises applying a negative back pressure to the template or a positive back pressure to the template.
4. The method of claim 1 , wherein applying the determined back pressure P b to the substrate comprises applying a negative back pressure to the substrate or a positive back pressure to the substrate.
5. The method of claim 1 , wherein applying the determined back pressure P t to the template, the determined back pressure P b to the substrate, or both comprises applying the determined back pressure prior to or concurrently with applying the separation force.
6. The method of claim 1 , wherein applying the determined back pressure P t to the template, the determined back pressure P b to the substrate, or both comprises applying only the determined back pressure P b or only the determined back pressure P t .
7. The method of claim 1 , wherein applying the determined back pressure P t to the template, the determined back pressure P b to the substrate, or both comprises applying a positive back pressure to the template and a negative back pressure to the substrate or applying a negative back pressure to the template and a positive back pressure to the substrate.
8. The method of claim 1 , further comprising determining a template thickness T t and a substrate thickness T b .
9. The method of claim 8 , wherein the determined back pressure P b applied to the substrate exceeds the back pressure applied to the template P t if T b exceeds T t .
10. The method of claim 8 , wherein the determined back pressure P t applied to the template exceeds the back pressure applied to the substrate P b if T t exceeds T b .