Aug. 4, 2016  2  US 2016/0223905 Al  DESCRIPTION OF THE PREFERRED  EMBODIMENTS  ti on-sensitive resin composition having a high depth of focus  (DOF) and a high exposure latitude (EL), and a pattern form› ing method using the same.  [0031]  Hereinafter, embodiments of the present invention  will be described in detail.  [0032]  In citations for a group (atomic group) in the present  specification, when the group is denoted without specifying  whether it is substituted or unsubstituted, the group includes  both a group not having a substituent and a group having a  substituent. For example, an "alkyl group" includes not only  an alkyl group not having a substituent (unsubstituted alkyl  group), but also an alkyl group having a substituent (substi› tuted alkyl group).  [0033]  "Active light" or "radiation" in the present specifi› cation means, for example, a bright line spectrum of a mer› cury lamp or the like, far ultraviolet rays represented by an  excimer laser, extreme ultraviolet rays (EUV light), X-rays,  electron beams (EB), or the like. In addition, in the present  invention, light means active light or radiation.  [0034]  Furthermore, "exposure" in the present specifica› tion includes, unless otherwise specified, not only exposure  by a mercury lamp, far ultraviolet rays represented by an  excimer laser, extreme ultraviolet rays (EUV light), X-rays,  or the like, but also writing by particle rays such as electron  beams and ion beams.  [0035]  Incidentally, in the present specification "(a value)  to ( a value)" is used to mean a range including the numeral  values represented before and after "to" as a lower limit value  and an upper limit value, respectively.  [0036]  Furthermore, in the present specification, (meth)  acrylate represents acrylate and methacrylate, and (meth)  acryl represents acryl and methacryl.  [0037]  [ Active Light or Radiation Sensitive Resin Compo› sition]  [0038]  The active light-sensitive or radiation-sensitive  resin composition of the present invention (hereinafter  referred to as simply the composition of the present inven› tion) is an active light-sensitive or radiation-sensitive resin  composition including a resin (A), a compound (B) capable of  generating an acid upon irradiation with active light or radia› tion, and a compound (C) having at least one oxygen atom.  However, the compound (C) does not include the resin (A)  and the compound (B). That is, the compound (C) is a com› pound different from the resin (A) and the compound (B), and  is distinguished from the resin (A) and the compound (B).  [0039]  The DOF and the EL of the composition of the  present invention can increase by taking the aforementioned  configuration. The reason therefor is not clear, but is pre› sumed to be approximately as follows.  [0040]  Generally, when a film (resist film) formed of a  composition including a resin (A) and a compound (B)  capable of generating an acid upon irradiation with active  light or radiation is exposed, an acid is generated from the  compound (B), and the generated acid changes the solubility  with respect to a developer of the resin (A). The generated  acid interacts with the resin (A) having the changed solubility  by, for example, hydrogen bond.  If such an interaction occurs,  the diffusion of the acid in the exposed area is excessively  inhibited, and as a result, the DOF or the EL decreases.  [0041]  On the other hand, as described above, the compo› sition of the present invention includes a compound (C) hav- ing at least one oxygen atom, and thus, the compound (C)  interacts with the resin (A) having the changed solubility,  whereby the interaction of the resin (A) having the changed  solubility with an acid generated from the compound (B) as  described above is weakened. As a result, the acid generated  from the compound (B) can be suitably diffused in the  exposed area, thereby improving the DOF and the EL.  [0042]  This is also presumed from high DOF and EL in the  case where the compound (C) is included (Examples), as  compared with a case where the compound (C) is not included  (Comparative Examples), as shown in Examples and Com› parative Examples which will be described later.  [0043]  Hereinafter, the resin (A), the compound (B)  capable of generating an acid upon irradiation with active  light or radiation, and the compound (C) having at least one  oxygen atom, and optional components which may be arbi› trarily included in the active light-sensitive or radiation-sen› sitive resin composition of the present invention will be  described.  [0044]  The active light-sensitive or radiation-sensitive  resin composition of the present invention is preferably for  ArF exposure, and more preferably for ArF liquid immersion  exposure.  [0045]  The active light-sensitive or radiation-sensitive  resin composition of the present invention may be either a  negative type resist composition for organic solvent develop› ment or a positive type resist composition for alkali develop› ment, but is preferably the negative type resist composition  for organic solvent development. Further, the composition  according to the present invention is typically a chemical  amplification type resist composition.  [0046]  <Resin (A)>  [0047]  The resin (A) included in the composition of the  present invention is typically a resin whose solubility with  respect to a developer changes as the resin decomposes by the  action of an acid.  It is preferably a resin whose solubility with  respect to an alkali developer increases by the action of an  acid or whose solubility with respect to a developer having an  organic solvent as a main component decreases by the action  of an acid; and preferably has a group capable of decompos› ing by the action ofan acid to generate an alkali-soluble group  (hereinafter sometimes referred to as an "acid-decomposable  group") on either one or both of the main chain and the side  chain of the resin. The resin (A) preferably has a group  capable of decomposing by the action of an acid to generate a  polar group.  [0048]  The resin (A) is preferably insoluble or sparingly  soluble in an alkali developer.  [0049]  Furthermore, even if the resin (A) is a compound  having an oxygen atom, it is not included in a compound (C)  which will be described later.  [0050]  The acid-decomposable group preferably has a  structure in which an alkali-soluble group is protected with a  group capable ofleaving by the decomposition by the action  ofan acid.  [0051]  Examples of the alkali-soluble group include a phe› nolic hydroxyl group, a carboxyl group, a fluorinated alcohol  group, a sulfonic acid group, a sulfonamide group, a sulfo› nylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene  group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis  (alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide  group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfo› nyl)imide group, a tris(alkylcarbonyl)methylene group, and a  tris(alkylsulfonyl)methylene group. 