Optical projection lithography using gradation stitching of the exposure fields

使用曝光场的渐变拼接的光学投影光刻

• 批准号: 11650050
• 负责人: HORIUCHI Toshiyuki
• 金额: $ 2.11万
• 依托单位: Tokyo Denki University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650050/
• 关键词: optical lithography; projection exposure; scan exposure; gradation stitching; field stitching; gradation field stitching; pattern stitching; dose uniformity; リソグラフィ; 露光フィールド

Optical projection lithography is one of the key technologies for fabricating advanced semiconductor devices. In order to obtaining highly integrated devices, chip sizes should be enlarged. However, it becomes very difficult to realize higher resolution for a larger exposure field. For this reason, a unique method for stitching small exposure fields smoothly and realizing large chip exposure was investigated in this research. In the new method, scan exposure is utilized, and either side of the fields are exposed with intensity gradation. Gradation of the neighborhood field side is controlled inversely to the initial field to be stitched. Thus, the total intensity at the stitched parts is kept constant and equals to the one at the non-stitched parts. Effectiveness of this gradation stitching exposure is demonstrated using a laboratory-built exposure system. After investigating convenient slit shapes, trapezoidal slits with an apex angle of 80゜ were adopted. As the first experimental sta … More ge, exposure dose uniformity and continuity of the stitched parts are evaluated at the reticle plane in order to eliminate the complicated influence of the projection optics on patterns printed on wafers. Exposure and development of a special resist the dissolved depth of which after development changes almost linearly with the exposure dose is utilized for detecting partial irregular dose distribution in the narrow stitched parts. It is clarified that the dose inequality in the stitched parts is successfully improved by adopting the new method. Moreover, it is proved that the changes of top-view profiles and line widths are also very small and negligible. As the second stage, pattern stitching for scan projection exposure is investigated. It is demonstrated that patterns in the stitched parts don't degrade even if the fields are stitched with certain intentional errors of positions. Error margin of the stitching positions becomes very large. It will become difficult to develop a high-resolution projection optics. with a large field for shorter wavelengths hereafter. Applying the gradation stitching exposure, large LSI chips will be replicated favorably by stitching two small scan fields. If a small field size is admissible, resolution and/or depth of focus will also be considerably improved. Less

光学投影光刻技术是制造先进半导体器件的关键技术之一。为了获得高集成度的器件，必须增大芯片尺寸。然而，对于更大的曝光场实现更高的分辨率变得非常困难。为此，本研究探索了一种能平滑拼接小曝光场，实现大芯片曝光的独特方法。该方法采用扫描曝光，并对视场两侧进行灰度分级曝光。与要缝合的初始场相反地控制邻近场侧的渐变。因此，缝合部分处的总强度保持恒定并且等于非缝合部分处的总强度。使用实验室构建的曝光系统证明了这种灰度拼接曝光的有效性。在研究了方便的狭缝形状后，采用了顶角为80 °的梯形狭缝。作为第一个实验阶段， ...更多信息 在掩模母版平面处评估拼接部分的曝光剂量均匀性和连续性，以消除投影光学器件对印刷在晶片上的图案的复杂影响。利用特殊抗蚀剂的曝光和显影来检测狭窄缝合部分中的局部不规则剂量分布，该抗蚀剂在显影后的溶解深度几乎与曝光剂量呈线性变化。结果表明，该方法成功地改善了缝合部位的剂量不均匀性。此外，证明了顶视轮廓和线宽的变化也很小，可以忽略不计。作为第二阶段，研究了扫描投影曝光的图案拼接。它表明，在缝合部分的图案不退化，即使字段被缝合与某些故意的位置误差。拼接位置的误差容限变得非常大。开发高分辨率的投影光学系统将变得困难。此后对于较短的波长具有大的场。应用灰度拼接曝光技术，通过拼接两个小扫描场，可以很好地复制大规模集成电路芯片。如果小的场尺寸是可接受的，则分辨率和/或焦深也将显著提高。少

项目成果

Toshiyuki Horiuchi et al.: "A New Projection Exposure Method Using a Liquid Crystal Display as a Switching Matrix in Place of a Reticle"Japanese Journal of Applied Physics. Vol.39,Part 1,No.1. 324-329 (2000)

Toshiyuki Horiuchi 等人：“一种使用液晶显示器作为切换矩阵代替十字线的新投影曝光方法”日本应用物理学杂志。

堀内敏行,持田裕行: "ぼかしフィールド接続スキャン露光によるフィールド接続境界平滑化の検討"東京電機大学工学部研究報告. No.48. 25-34 (2000)

Toshiyuki Horiuchi、Hiroyuki Mochida：“通过模糊场连接扫描曝光进行场连接边界平滑的研究”东京电机大学工学部研究报告第 48. 25-34 号（2000 年）。

Toshiyuki Horiuchi et al.: "Gradation Stitching Exposure Performance in the Improvement of Dose Uniformity and Continuity at the Field Stitching Boundaries"Japanese Journal of Applied Physics. Vol.40(to be published). (2001)

Toshiyuki Horiuchi 等人：“在场拼接边界处改善剂量均匀性和连续性的分级拼接曝光性能”日本应用物理学杂志。

堀内敏行,成田剛: "光リソグラフィによる集積回路微細パタン転写の高密度化に関する研究"双葉電子記念財団年報. No.5. 124-129 (1999)

Toshiyuki Horiuchi、Tsuyoshi Narita：“利用光刻技术对集成电路中精细图案进行高密度转移的研究”双叶电子纪念基金会年度报告第 5. 124-129 号（1999 年）。

Toshiyuki Horiuchi et al.: "A New Projection Exposure Method Using A Liquid Crystal Display as a Switching Matrix in Place of a Reticle"Japanese Journal of Applied Physics. Vol.39. 324-329 (2000)

Toshiyuki Horiuchi 等人：“一种使用液晶显示器作为切换矩阵代替十字线的新投影曝光方法”日本应用物理学杂志。