JP-7856430-B2 - Film structure for electric field-induced photoresist pattern formation process

Inventors

• ダイ， ホイシオン
• バンガー， マンゲシュ
• ンガイ， クリストファー エス．
• ネマニ， シュリーニヴァース ディー．
• イー， エリー ワイ．
• ウェルチ， スティーブン ハイローング

Assignees

• アプライド マテリアルズ インコーポレイテッド

Dates

Publication Date

20260511

Application Date

20191011

Priority Date

20190118

Claims (12)

1. A method for processing a substrate, The process involves adding a photoresist layer containing a photoacid generator to a multilayer arranged on a substrate, wherein the multilayer includes a lower layer containing the photoacid generator and in contact with the photoresist layer. Exposing a first portion of the photoresist layer not protected by a photomask to radiation light in a lithography exposure process, and applying an electric or magnetic field to move the photoacid generated from the photoacid generator in the lower layer to the photoresist layer, thereby substantially changing the movement of the photoacid within the photoresist layer in a vertical direction. Methods that include...
2. The method according to claim 1, further comprising baking the photoresist layer and the underlying layer, and applying an electric field or a magnetic field while baking the photoresist layer and the underlying layer.
3. The method according to claim 1, wherein the electric field or magnetic field is applied to the photoresist layer during the lithography exposure process.
4. The method according to claim 2 , further comprising performing a pre-baking step on the photoresist layer and the underlying layer disposed on the substrate, wherein the electric field or the magnetic field is applied to the photoresist layer during the pre-baking step.
5. The method according to claim 1, wherein the lower layer contains the photoacid generator in an organic polymer solvent.
6. The method according to claim 5, wherein the organic polymer solvent is selected from the group consisting of propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), propylene glycol methyl ether (PGME), propylene glycol n-propyl ether (PnP), cyclohexanone, acetone, gamma-butyrolactone (GBL), and mixtures thereof.
7. The method according to claim 1, wherein the multilayer further includes a hard mask layer disposed below the lower layer and on the substrate.
8. The method according to claim 7, wherein the hard mask layer is selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, amorphous carbon, doped amorphous carbon, TEOS oxide, USG, SOG, organosilicon, oxide-containing material titanium nitride, titanium oxynitride, and combinations thereof .
9. A method for processing a substrate, Adding a photoresist layer that is located on a lower layer containing a photoacid generator placed on a substrate and is in contact with the lower layer, Exposing the first portion of the photoresist layer that is not protected by the photomask to radiation light in a lithography exposure process, A method comprising performing a baking step on the photoresist layer and the underlying layer, and while performing the baking step, applying an electric or magnetic field to move the photoacid generated from the photoacid generator in the underlying layer to the photoresist layer, thereby substantially changing the movement of the photoacid in the photoresist layer in a vertical direction .
10. Exposing the first portion of the photoresist layer is The method according to claim 9 , further comprising applying an electric field or a magnetic field while performing the lithography exposure step.
11. The method according to claim 9 , wherein the lower layer is an organic material.
12. The method according to claim 11, wherein the lower layer contains the photoacid generator in an organic solvent.

Description

[0001] This disclosure broadly relates to methods and apparatus for processing substrates, and more particularly to methods and apparatus for improving photoresist profile control. [0002] Integrated circuits have evolved into complex devices capable of housing millions of components (e.g., transistors, capacitors, and resistors) on a single chip. Photolithography can be used to form components on a chip. Generally, the photolithography process involves several basic steps. First, a photoresist layer is formed on the substrate. This photoresist layer may be formed, for example, by spin coating. The photoresist layer may contain a resist resin and a photoacid generator. When the photoacid generator is exposed to electromagnetic radiation in the subsequent exposure step, it alters the solubility of the photoresist in the development process. The electromagnetic radiation may have any preferred wavelength, such as wavelengths in the extreme ultraviolet region. The electromagnetic radiation may come from any preferred source, such as a 193 nm ArF laser, electron beam, ion beam, or other source. Next, in a pre-exposure bake step, excess solvent may be removed. [0003] In the exposure stage, a photomask or reticle may be used to selectively expose a specific area of the photoresist layer on the substrate to electromagnetic radiation. Other exposure methods may be maskless exposure methods. Upon exposure, the photoacid generator decomposes, generating acid which may create a latent acid image within the resist resin. After exposure, the substrate may be heated in a post-exposure bake process. During the post-exposure bake process, the acid generated by the photoacid generator reacts with the resist resin in the photoresist layer, altering the solubility of the resist in the photoresist layer during the subsequent development process. [0004] After exposure and baking, the substrate (particularly the photoresist layer) can be developed and rinsed. Then, after development and rinsing, a patterned photoresist layer is formed on the substrate, as shown in Figure 1. Figure 1 shows an exemplary top cross-sectional view of a substrate 100 having a patterned photoresist layer 104 placed on a target material 102 to be etched. Openings 106 are defined between the patterned photoresist layers 104 so that, after the development and rinsing process, the underlying target material 102 is exposed and etched, transferring features onto the target material 102. However, improper control or low resolution of the lithography exposure process can lead to inaccurate limit dimensions of the photoresist layer 104, resulting in unacceptable linewidth roughness (LWR) 108. Furthermore, during the exposure process, the acid generated from the photoacid generator (shown in Figure 1) may randomly diffuse into any region, including areas protected under the mask that are not intended to be diffused, thus generating undesirable wiggling or roughness profiles 150 at the edges or interfaces of the patterned photoresist layer 104 interfaced with the opening 106. The large linewidth roughness (LWR) 108 and undesirable wiggling profiles 150 of the photoresist layer 104 result in inaccurate feature transfer to the target material 102, and thus ultimately lead to device failure and yield loss. [0005] Therefore, in order to obtain a patterned photoresist layer having the desired limit dimensions, methods and apparatus are needed to control the linewidth roughness (LWR) and improve resolution as well as dose sensitivity. [0006] Embodiments of the present disclosure include a method for forming a film structure for efficiently controlling the distribution and diffusion of acid from a photoacid generator within a photoresist layer during an exposure process or a pre-exposure or post-exposure baking process. In one embodiment, the device structure includes a film structure disposed on a substrate and a plurality of openings formed within the film structure, wherein the openings formed across the substrate have a limit dimensional uniformity of approximately 1 nm to 2 nm. [0007] In another embodiment, a method for processing a substrate includes adding a photoresist layer containing a photoacid generator to a multilayer disposed on the substrate, wherein the multilayer includes a lower layer formed from an organic material, an inorganic material, or a mixture of an organic material and an inorganic material, and the method further includes exposing a first portion of the photoresist layer not protected by a photomask to radiation light in a lithography exposure step, and applying an electric or magnetic field to substantially alter the movement of the photoacid generated from the photoacid generator in a vertical direction. [0008] In yet another embodiment, a method for processing a substrate includes: adding a photoresist layer on a lower layer placed on the substrate; exposing a first portion of the photoresist layer not protected by a photomask to radiation