Name: photolithography for silicon wafer patterning
Uploaded: 2023-04-30T06:32:27.000Z
Duration: 7 min 44 s
Channel: JoVE

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对能够处理极小样本体积的便携式设备日益增长的需求，推动了被称为生物微机电系统（BioMEMs）的设备微型化发展。BioMEMs&#160;通过微加工技术制造，该技术利用半导体工艺来构建微米尺度的结构。一种名为光刻技术的微加工方法，常被用来通过光照在基底上形成复杂的图形。本视频将介绍光刻技术的原理，在实验室中演示该技术的操作过程，并展示光刻技术在若干应用领域中的实际用途。
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<div class="chapter_text" id="script_1">
半导体，特别是硅晶圆，通常在光刻微加工中用作基底材料。首先，晶圆需经过清洗以去除有机污染物。随后在表面形成一层基底材料，例如通过热氧化法生成二氧化硅层。光刻过程开始时，将一层黏稠且对紫外光敏感的物质——光刻胶，通过旋转涂布的方式均匀地覆盖在基底上。接着，将涂有光刻胶的基底通过一个精确设计图案的模板（称为光掩模）暴露于强紫外光下。光刻胶分为两种类型：正性光刻胶在紫外光照射后变得可溶；而负性光刻胶则在曝光区域发生交联，从而变得不溶。随后使用显影液去除可溶部分的光刻胶，留下具有特定图案的光刻胶以及暴露出来的基底区域。接下来，将该图案刻蚀到暴露的二氧化硅层中。一种称为反应离子刻蚀的干法刻蚀技术利用化学活性等离子体去除沉积在晶圆上的材料；或者也可采用湿法刻蚀，例如使用氢氟酸来刻蚀二氧化硅。所采用的刻蚀技术取决于待处理材料的性质。最后，去除剩余的光刻胶，留下精确图案化的硅微结构。该结构可直接使用，也可作为制造电子器件和微流控器件的模具。在已了解光刻基本流程之后，接下来让我们看看如何在洁净室环境中实际操作这一过程。
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<div class="chapter_text" id="script_2">
首先，设计用于创建图案的光掩模，并从制造商处订购。然后，在洁净室中进行光刻工艺，洁净室会定期过滤空气，以最大限度地减少灰尘污染。首先，通过热氧化在硅晶圆表面形成一层二氧化硅。晶圆氧化后，将其放置在旋涂机的卡盘上。将光刻胶倒入晶圆中心，直至覆盖晶圆大部分表面。随后对光刻胶进行旋涂&#160;，形成均匀且&#160;薄的涂层。接下来，将涂覆好的晶圆放在热板上进行前烘&#160;，以蒸发残留溶剂并固化光刻胶。将晶圆装入掩模对准器中，其中包含所需图案对应的特定光掩模。然后，通过光掩模对晶圆进行紫外光曝光，再进行后烘以固定已显影的光刻胶。使用与所用光刻胶类型相匹配的显影液去除可溶性区域的光刻胶。最后，将晶圆冲洗并干燥，使图案化的光刻胶保留在晶圆上。
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光刻完成后，使用深反应离子刻蚀技术将图案刻蚀到二氧化硅顶层。刻蚀后，将晶圆浸泡在适当的光刻胶去除剂中以去除残留的光刻胶。随后用异丙醇和丙酮冲洗晶圆，并在氮气下吹干。接下来，配制piranha清洗液以去除多余的有机残留物。piranha溶液是浓硫酸和过氧化氢的混合物。该溶液必须在经过认证且通风良好的通风橱中，并在经过适当培训后使用。piranha溶液极其危险，可能引发爆炸。将晶圆浸入piranha溶液中数分钟，然后用水冲洗。最后，用丙酮和甲醇冲洗晶圆，并用氮气吹干，得到洁净的最终结构。
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<div class="chapter_text" id="script_4">
通过光刻技术生成的微米级图案被用于制造各种生物微机电系统（BioMEM&#160;）器件。例如，光刻可用于在基底（如硅晶圆或玻璃载片）上形成金属图案。该方法并非蚀刻去除基底的顶层，而是在光刻胶图案上通过溅射镀膜或金属蒸发的方式沉积金属。在此示例中，先在玻璃载片上涂覆一层铬作为粘附层，随后再沉积一层金。沉积完成后，去除光刻胶以暴露出金图案。这些金图案可用于实现细胞的可控组装，或作为生物电子器件中的电极。光刻技术也可用于制造聚合物微米图案。在此类应用中，需在光刻前先在硅晶圆表面沉积一层聚合物。与硅晶圆上的二氧化硅层类似，经显影后暴露的聚合物区域将被蚀刻去除，随后清除残留的光刻胶，仅留下图案化的聚合物结构。这些图案化的聚合物可用于诱导细胞在聚合物岛内部或周围进行可控生长。尽管光刻技术主要限于微米尺度，但纳米尺度的图案可通过聚焦离子束（FIB）技术实现。FIB利用离子束在表面精确地进行材料的去除或沉积，从而形成特定图案。在此示例中，预先图案化的金电极被功能化修饰上钼晶体，随后利用FIB沉积纳米尺度的铂桥，将晶体与金电极连接。这些结构可用于提升生物微机电系统（BioMEM&#160;）器件的性能并进一步实现其微型化。
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<div class="chapter_text" id="script_5">
您刚刚观看了 JoVE 关于通过光刻技术进行微加工的简介。现在，您应该理解了光刻的基本流程、其在实验室中的操作方法，以及该技术在生物微机电系统（BioMEM&#160;devices）制造中的一些应用。感谢观看。
</div>

通过光刻技术进行微加工

生物微机电系统（BioMEM&#160;）器件的制备通常采用一种称为光刻的微加工技术。这种广泛应用的方法利用光将图案转移到硅片上，为多种类型的生物微机电系统（BioMEM&#160;）器件的制备提供了基础。
本视频介绍了光刻技术，展示了在洁净室中执行该工艺的步骤，并概述了该工艺的一些应用。

生物微机电系统（BioMEM&#160;）器件的制备通常采用一种称为光刻的微加工技术。这种广泛应用的方法利用光将图案转移到硅片上，为多种类型的生物微机电系统（BioMEM&#160;）器件的制备提供了基础。
本视频介绍了光刻技术，展示了在洁净室中如何进行该工艺，并概述了该工艺的一些应用。

BioMEM 器件的制备通常采用一种称为光刻的微加工技术。这种广泛应用的方法利用光来……

对便携式设备日益增长的需求，以及对极小样本体积的要求，推动了被称为生物微机电系统（BioMEMs）的设备微型化发展。BioMEMs 通过微加工技术制造，该技术利用半导体工艺来制备微米尺度的结构。其中一种常用的微加工技术称为光刻（photolithography），它利用光在基底上形成复杂图案。本视频将介绍光刻工艺的基本原理，在实验室中演示该技术的操作过程，并展示光刻技术的一些实际应用。半导体，特别是硅晶圆，通常在光刻微加工中用作基底材料。首先，晶圆需经过清洗以去除有机污染物。随后在表面形成一层基底材料，例如通过热氧化法生成二氧化硅层。光刻过程开始时，将一层黏稠且对紫外光敏感的物质——光刻胶，通过旋转涂布的方式均匀地覆盖在基底表面。涂覆了光刻胶的基底随后通过一个精确设计图案的模板（称为光掩模）暴露于强紫外光下。光刻胶分为两种类型：正性光刻胶在紫外光照射后变得可溶；而负性光刻胶则在曝光区域发生交联，从而变得不溶。接着使用显影液去除可溶部分的光刻胶，留下具有特定图案的光刻胶以及暴露出来的基底区域。随后将该图案刻蚀到暴露的二氧化硅层中。一种称为反应离子刻蚀的干法刻蚀技术利用化学活性等离子体去除沉积在晶圆上的材料； alternatively，也可使用湿法刻蚀，例如氢氟酸来刻蚀二氧化硅。所采用的刻蚀技术取决于待处理材料的性质。最后，去除剩余的光刻胶，留下精确图案化的硅微结构。该结构可直接使用，或作为制造电子器件和微流控器件的模具。在已了解光刻基本流程之后，接下来将介绍如何在洁净室环境中实际操作该流程。首先，设计用于创建图案的光掩模，并从制造商处订购。然后，在洁净室中进行光刻工艺，洁净室会定期过滤空气，以最大限度地减少灰尘污染。首先，通过热氧化在硅晶圆表面形成一层二氧化硅。晶圆氧化后，将其放置在匀胶机的卡盘上。将光刻胶倒入晶圆中心，直至覆盖晶圆大部分表面。随后通过旋转涂布形成均匀且薄的光刻胶涂层。接下来，将涂覆好的晶圆放在热板上进行前烘，以蒸发残留溶剂并固化光刻胶。将晶圆装入掩模对准仪中，该仪器包含所需图案对应的特定光掩模。然后，通过光掩模对晶圆进行紫外光曝光，再进行坚膜烘烤以固定已显影的光刻胶。使用与所用光刻胶类型相匹配的显影液去除可溶性区域的光刻胶。最后，对晶圆进行冲洗和干燥，使图案化的光刻胶保留在晶圆上。经过光刻后，利用深反应离子刻蚀技术将图案刻蚀到二氧化硅的顶层。刻蚀完成后，将晶圆浸泡在适当的光刻胶去除剂中以去除残留的光刻胶。随后用异丙醇和丙酮冲洗晶圆，并在氮气下吹干。接下来，配制piranha清洗液以去除多余的有机残留物。piranha溶液是浓硫酸与过氧化氢的混合物。该溶液必须在经过认证且通风良好的通风橱中，并在经过适当培训的情况下使用。piranha溶液极其危险，可能引发爆炸。将晶圆浸入piranha溶液中数分钟，然后用水冲洗。最后，用丙酮和甲醇冲洗晶圆，并用氮气吹干，得到洁净的最终结构。通过光刻技术生成的微米级图案被用于制造多种生物微机电系统（BioMEMS）器件。例如，光刻可用于在基底（如硅晶圆或玻璃载片）上形成金属图案。该方法不是蚀刻去除基底的顶层，而是在光刻胶图案上通过溅射镀膜或金属蒸发的方式沉积金属。在此示例中，首先在玻璃载片上涂覆一层铬作为粘附层，随后再沉积一层金。沉积完成后，去除光刻胶以暴露出金的图案。这些金图案可用于细胞的可控组装，或作为生物电子器件中的电极。光刻技术也可用于制造聚合物微图案。在此过程中，先在硅晶圆表面沉积一层聚合物，再进行光刻。与硅晶圆上的二氧化硅层类似，经显影后暴露的聚合物区域将被蚀刻去除，随后去除残留的光刻胶，仅留下图案化的聚合物结构。这种图案化聚合物可用于诱导细胞在聚合物岛区域或其周围进行可控生长。尽管光刻技术主要局限于微米尺度，但纳米尺度的图案可通过聚焦离子束（FIB）技术实现。FIB利用离子束在表面精确地去除或沉积材料以形成特定图案。在此示例中，预先制备的金电极被修饰上钼晶体，随后使用FIB沉积纳米级铂桥，将晶体与金电极连接。这些结构可用于提升生物微机电系统器件的性能并进一步实现小型化。您刚刚观看了 JoVE 关于通过光刻技术进行微加工的简介视频。您现在应该理解了光刻技术的基本流程、其在实验室中的操作方法，以及该技术在生物微机电系统（BioMEMS）器件制造中的一些应用方式。感谢观看。

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Microfabrication via Photolithography

通过光刻的微细加工

photolithography for silicon wafer patterning

Photolithography is a common microfabrication method used to pattern a silicon wafer. It uses light to transfer a design onto the wafer surface. This process helps form the basis for many BioMEM devices.

The page also shows how photolithography is carried out in a cleanroom. Cleanroom steps are important because they support careful fabrication of small, detailed features. The video ends by introducing applications of this process in BioMEM device production.

Photolithography for Silicon Wafer Patterning

photolithography-for-silicon-wafer-patterning

overview of biomaterials

Biomaterials in Medicine and Engineering

Biomaterials are materials designed to interact well with biological organisms or molecules. They may come from an organism, be produced by an organism, or be made as a synthetic polymer. Because of these properties, engineers use biomaterials in medicine and other biological applications. These materials are used in tissue engineering, biosensing, and drug delivery. Tissue engineering uses materials to support the growth or repair of tissues. Biosensing uses materials to detect biological...

collagen hydrogels

Porcine Collagen for Tissue Engineering

Collagen is a useful biomaterial with uses that go beyond the lab. It has also found commercial use in photography. In tissue engineering, collagen can be turned into hydrogels that give engineered tissue support and structure. This page follows the path from porcine skin to a collagen hydrogel. Porcine skin is used as the source of collagen. The material is then prepared for use in tissue engineering applications. The video also shows several applications of collagen and the methods used to...

electrospinning of silk biomaterials

Silk Cocoon Processing for Fiber Mats

Silk cocoons can be processed into a soluble material that is useful for making biomaterials. Silk fibers have been used for fabrics and threads for centuries, but turning them into a versatile pre-polymer solution is a newer technique. That solution can then be shaped into materials with controllable mechanical properties. The process begins with silk worm cocoons. The silk is solubilized, or dissolved, so it can be handled as a liquid-like solution. The video then shows how that silk...

overview of biomem devices

BioMEMs in Diagnostics and Miniaturization

Bio-microelectromechanical systems, or BioMEMs, are microscale devices used in diagnostic settings. They work with very small sample and reagent volumes in vivo and in vitro, which means inside a living body or outside it in a lab. These compact systems support bioengineering research and help make diagnostic tools more efficient. BioMEMs can carry out functions such as filtration, sensing, and synthesis on a tiny scale. Using less material can lower costs and improve sensitivity. The...

microfabrication via photolithography

Photolithography is a common microfabrication method used to pattern a silicon wafer. It uses light to transfer a design onto the wafer surface. This process helps form the basis for many BioMEM devices. The page also shows how photolithography is carried out in a cleanroom. Cleanroom steps are important because they support careful fabrication of small, detailed features. The video ends by introducing applications of this process in BioMEM device production.

soft lithography

Photolithography for Microfluidic Device Making

Photolithography and soft lithography are used to make BioMEM devices such as microfluidic channels. A microscale pattern is copied by curing an elastomeric polymer over a 3D structure. The result is a polymer piece that can serve as part of a biological device. These polymer structures are then used to build a range of tools. Some are microfluidic channels for biosensing applications. Others are microscale bioreactors that let scientists visualize micro-colonies. The process also shows how...

overview of bioprocess engineering

Bioreactors and Protein Production in Bioprocessing

Bioprocessing uses living organisms to make a desired target product. In many cases, that product is a protein made in a bioreactor, which is a controlled vessel for growing cells. This process often relies on genetically engineered organisms. Engineers design the system so the cells can produce proteins at large scale. That approach is central to making biotherapeutics, which are drugs made from biological materials. Biotherapeutics are important medicines for complex diseases such as...

synthetic biology

Engineering Cells to Produce Proteins

Synthetic biology is a bioengineering method for programming cells to make useful products. In many cases, the goal is to genetically modify an organism so it can produce large amounts of a protein. That protein may already be made by the cell, or it may come from a newly inserted DNA sequence. The process depends on changing an organism’s genetic material. This is done with transformation or transfection, two common ways to introduce DNA into cells. The video also shows how this work is...

batch and continuous bioreactors

Growing Cells in Bioreactors

Bioreactors are used to grow organisms in large volumes. This makes it possible to produce large amounts of a target product. In laboratory and bioengineering settings, they provide a controlled place for cell growth and product formation. The two main reactor types are batch reactors and continuous reactors. A batch reactor contains all of the materials needed for cell growth at the start. A continuous reactor has inlet and outlet ports, so fresh growth media can be added while cell waste is...

overview of biosensing

How Biosensors Detect Molecules

Biosensors detect biological molecules and chemical contaminants by combining biology with physical measurement. They can identify targets such as proteins or cells, as well as non-biological molecules like chemicals or contaminants. This makes biosensing a useful field for studying and monitoring many kinds of samples. These devices rely on different signal types to find the target molecule. Some biosensors use electrical signals, while others depend on optical, electrochemical, or mechanical...

electrochemical biosensing

Glucose Sensors and Cancer Detection

Electrochemical biosensors detect target molecules by measuring an oxidation-reduction event. That signal changes when a molecule binds to the sensor surface. These sensors helped shape modern biosensing after the first glucose biosensor was invented. The glucose biosensor is a key example of this technology. It shows how electrochemical sensing can track a biological target through a measurable electrical change. The same basic idea also helps explain how electrochemical biosensors can be...

optical biosensing

Detecting Molecules with Light

Optical biosensors detect target molecules with light. They monitor binding by reading an optical signal from the sample. This makes them useful for seeing when a target molecule is present. Some optical biosensors use a label molecule. The label creates a measurable signal, such as fluorescence. Other optical biosensors are label-free and track changes in optical properties, such as refractive index, as binding occurs. This page introduces both label and label-free optical biosensors. It...

overview of tissue engineering

Building Artificial Tissue with Biomaterials

Tissue engineering uses biomaterials, specific cells, and growth factors to build artificial tissue. These engineered tissue constructs are designed for tissue repair and, in some cases, organ replacement. The field focuses on how to make tissue work like natural tissue. It begins with a scaffold, which is a structure that supports cell growth. Cells are then added to the scaffold, and growth factors help encourage proliferation, or cell multiplication. The video also outlines common methods...

histotypic tissue culture

3D Cell Growth on Engineered Matrices

Histotypic tissue culture uses an engineered three-dimensional matrix to grow and propagate cells. Compared with common two-dimensional tissue culture, cells in a 3D setting behave more realistically and better mimic native tissue. The method is useful when high cell density is needed. The process begins by harvesting cells from donor tissue. Those cells are then placed onto an engineered construct for culture. This setup supports growth in a three-dimensional space instead of a flat surface.

whole organ tissue culture

Lung Decellularization and Recellularization

Whole organs can be cultured ex vivo using specialized bioreactors to support repair or replacement of entire organs. In this approach, a donor organ is first stripped of all cells. What remains is the three-dimensional structure of the organ, which can then be repopulated with new cells. The lung is the example shown here. The method uses a dynamic culture system that provides mechanical stimulation, similar to what the organ experiences in the body. This type of culture helps induce native...

bioengineering

该系列涵盖了核心生物工程概念, 包括生物材料的生产、histotypic 和整个器官组织培养、生物技术, 以及 bioMEMs 和传感的复杂系统级领域。

See how photolithography uses light to pattern a silicon wafer in a cleanroom and supports the fabrication of BioMEM devices and related applications.

Photolithography for Silicon Wafer Patterning

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