低介電質材料室溫奈米壓印技術之開發與電性及可靠度之研究

本論文研究主要分為兩部分，第一部分為利用低介電質材料實現於室溫下奈米壓印。我們利用溶劑輔助壓印低介電質材料的方式調整奈米壓印的參數完成室溫奈米壓印，在這實驗中，最佳調整的參數是將樣品浸置溶劑氣體環境中30分鐘，並且在壓力25 bar的壓力下壓印1小時，最後經過40℃/30s之後脫模完成圖形的轉移。在論文的第二部分，主要研究低介電質材料經不同退火溫度後，觀察其薄膜特性的變化。實驗結果顯示，PECVD所沉積的low-k薄膜其熱穩定度大約在700℃。在退火溫度600℃之前，未摻雜porogen的low-k薄膜在各分析上幾乎沒有明顯的改變，而有摻雜porogen的low-k薄膜會因為porogen的移除產生孔洞造成較低的介電常數。此外，由於孔洞的產生也會增加薄膜內的電荷載體途徑，因此會有較差的電特性。雖然有摻雜porogen的low-k的薄膜利用UV光退火和熱退火同樣可以將porogen移除造成較低的介電常數，但利用UV光退火相較於熱退火擁有較佳的機械特性和電特性。當退火溫度超過薄膜的熱穩定度時，薄膜內的Si-CH3鍵結會開始被破壞而形成Si-OH的親水性鍵結，而這種鍵結也就會造成low-k薄膜的介電常數的上升和表面親水性的增加，在電性可靠度的分析上可以得到未摻雜porogen的low-k薄膜其電性並不會受到溫度的影響，而有摻雜porogen經過UV光處理的low-k薄膜，其電性會由於高溫退火將薄膜內殘餘porogen的移除而增強崩潰電壓以及崩潰時間，但有摻雜porogen未經過UV光處理的low-k薄膜卻會因為高溫退火造成薄膜內孔洞的產生而降低其崩潰電壓以及時間。

關鍵字

低介電質材料；low-k 奈米壓印；PECVD 熱穩定；電特性；可靠度

並列摘要

This study consists of two parts. The first part is to evaluate the room temperature nanoimprint on the low dielectric material. We used a solvent-vapor-assisted imprint method in a low dielectric material to achieve the room temperature nanoimprint by adjusting the nanoimprint parameters. In this study, the optimized nanoimprint conditions are as follows: 30 min immersion time in methyl isobutyl ketone (MIBK) vapor, 25 bar down-force, 1 hour impressing time, and 40℃/30s demolding time. Therefore, we demonstrated that a low-k material (MSQ) can be directly patterned by nanoimprint lithography using the solvent-vapor-assisted method in the room temperature. The second part is to study the thermal stability of various low dielectric materials. The experimental results indicate that the low-k films deposited by plasma-enhanced chemical vapor deposition (PECVD) are thermally stable as the annealing temperature below 700℃. When the annealing temperature exceeds 700℃ the Si-CH3 bonds in the low-k films will be destroyed and react with water to form the Si-OH hydrophilic bonds. These bonds cause an increase in the dielectric constant and turn the surface to be more hydrophilic. The low-k films without porogen remain unchanged and are more stable as compared to those with porogen. On the other hand, the low-k films with porogen have a lower dielectric constant as the porogen are removed by ultraviolet (UV) curing or thermal treatments with the temperature above 500℃. Although the pore in the low-k films can be generated by UV curing and thermal treatment, UV curing process has better mechanical and electrical characteristics. Additionally, the low-k films with pores show poor electrical characteristics because the pore within the low-k films can be served as a pathway for charge carriers. In reliability testing results, the electrical characteristics are not affected by the annealing temperature for the low-k films without porogen. On the other hand, the low-k films with porogen show a different trend for the low-k samples with UV curing and without UV curing samples. The porous low-k films with UV curing process show a higher breakdown voltage and breakdown time after the high temperature annealing of 600℃. This increase is possibly caused by the removal of the residual in the pore. For the low-k films with porogen without UV curing, the breakdown voltage and breakdown time significantly decrease after the high temperature annealing of 600℃, due to the generation of pores within the film.