Dielectric erosion and Cu dishing after Cu CMP
Chemical mechanical polishing (CMP) is a powerful fabrication technique that uses chemical oxidation and mechanical abrasion to remove material.
CMP process Steps
Surface preparation: The substrate’s surface is cleaned to get rid of any impurities or extra material. This step is important to make sure the substrate surface is free of flaws that can impair the polishing procedure.
Application of the slurry: The substrate’s surface is coated with the slurry, which is a mixture of abrasive particles and chemical reactants. Usually, a spin-coater or a dispensing nozzle is used to disperse the slurry.
Polishing: The substrate is then put on a polishing pad and pressed against it while being rotated and subjected to regulated pressure. The slurry’s chemical reactants aid in the breakdown of the material to be removed while the abrasive particles in the slurry interact with the substrate surface to remove material.
Rinsing: To eliminate any remaining slurry and particles from the surface of the substrate, a cleaning solution is used to rinse it after the polishing stage. This step is important to make sure the substrate is clear of any impurities that can adversely affect the rest of the processes.
Drying: After removing any remaining cleaning solution, the substrate is dried. This technique is important to stop impurities or flaws from entering the substrate during later processing processes.
Inspection: The polished substrate is then examined to assess the polished surface’s quality and confirm that the desired planarity and roughness requirements have been satisfied.
In order to produce high-quality results during the important CMP step of the production of microelectronic devices, it is important to carefully manage the process parameters. Depending on the individual application and the materials being treated, the specific steps in a CMP process may change.
Why we are maintaining Desity in Layout Design.
We maintain minimum and maximum density in the Layout to avoid dishing and erosion problems in Layout. In Chemical Mechanical Planarization (CMP) process, dishing and erosion are two common issues that can arise during the polishing process. Let’s understand, what is this.
What is dishing problem in CMP?
When the CMP process removes more material from the center of the surface than from the edges, a concave depression known as “dishing” might appear on the surface being polished. Dishing can happen for a number of reasons, including uneven pressure distribution, uneven slurry distribution, and uneven pad wear. To avoid the Dishing problem in Layout, we should maintain the Minimum Density of a particular layer in the layout.
What is Eroision problem in CMP?
As was said in a previous comment, erosion describes the chemical removal of particles from the polished surface. Erosion can happen during CMP when chemical reactants in the slurry combine with the surface to generate a combination that the slurry’s abrasive particles can remove more quickly. To avoid the Erosion problem in Layout, we should maintain the Maximum Density of a particular layer in the layout.
What is Minimum density in Layout design?
A major portion of layout design is minimum density, which establishes the minimum amount of components and interconnects that can be arranged in a given space. A high percentage of working circuits are produced throughout the manufacturing process, the power consumption and silicon area requirements are met, and the circuits on the layout perform as efficiently as possible while the minimal density is maintained.
A number of variables, such as the process technology, the intended circuit performance, the acceptable power consumption, and the desired manufacturing yield, might affect the minimum density requirements for a specific layout design. These elements must be carefully taken into account, and the minimum density requirements must be optimized to meet the specific design requirements.
What is Maximum density in Layout design?
When designing a layout, maximum density means fitting the most components, interconnects, and other features into a given space. The highest number of features that may be accommodated in a given space while still achieving the appropriate performance, yield, and manufacturing requirements is known as the maximum density. This maximum density is typically represented as a percentage of the entire area that is available.
Maximum density, which establishes the maximum number of components and interconnects that can be installed in a given area, is an important component in layout design. Maintaining maximum density guarantees that the circuits on the layout function at their best and that a large portion of the circuits produced by the manufacturing process are functional.