Patent Application
20060099828
1Field of the Invention
The present invention relates to a semiconductor process and a photoresist-coating process, and more particularly, to a semiconductor process and a photoresist-coating process that keep the substrate in a spinning state before coating photoresist in order to prevent defects therein.
2Description of the Related Art
Photolithography is a vital process in the semiconductor manufacturing technology. It has been broadly applied in the process, for example, in patterning various film layers and in ion implantation.
A photolithographic process comprises the steps of photoresist coating, exposure and film development. Wherein, photoresist coating is an essential part in the photolithographic process. The prior photoresist-coating method starts by placing a substrate on the table of the spinner. The substrate is sucked on the table by proper vacuum degree provided through the axis of the spinner. The photoresist is then applied on the substrate. When the spinner starts spinning the substrate, the centrifugal force enables the photoresist to be spun over the substrate and a photoresist layer is thus formed.
After the formation of the photoresist layer, a baking process follows, wherein the solvent is removed from the photoresist layer. It should be noted that the formed photoresist layer in the conventional photoresist-coating process tends to have defects. These defects can be, for example, gaps or cracks in the photoresist layer. These defects have great consequence on the subsequent exposure and film development process, and may cause misalignment during the photolithographic process and therefore destroy the integrity of the photolithographic pattern. They may even impair the reliabilities and yields of the semiconductor devices. In particular, when the sizes of semiconductor devices shrink to deep sub-micron dimensions in which 193-nm photolithographic process should be applied, the defects become even more obvious.
Accordingly, the present invention is directed to a semiconductor process in which a new photoresist-coating method is applied to avoid the defects during a photoresist coating process that may trouble subsequent process.
The present invention is also directed to a photoresist-coating method to avoid the defects formed during a photoresist-coating process such that a desired photoresist layer can be formed and the reliability and yield of the semiconductor devices can be improved.
The present invention provides a semiconductor process. The process starts by dampening a substrate with a chemical before coating photoresist over the substrate, wherein the substrate is kept in a spinning state while the chemical is applied.
According to one embodiment of the semiconductor process in the present invention, when the chemical is applied on the substrate, the substrate starts spinning.
According to one embodiment of the semiconductor process in the present invention, before the chemical is applied on the substrate, the substrate starts spinning.
According to one embodiment of the semiconductor process in the present invention, a time to apply the chemical is more than about 3 seconds. More preferably, the semiconductor process further comprises the step of spinning the chemical over the substrate within a timeframe from about 0.6 second to about 2 seconds.
According to one embodiment of the semiconductor process in the present invention, the said chemical comprises edge backside rinse (EBR).
The present invention also provides a photoresist-coating method. The photoresist-coating method starts by spinning a substrate at a first speed. Next, a chemical is applied on a surface of the spinning substrate to dampen the surface. Then, photoresist is coated over the surface of the substrate.
According to one embodiment of the photoresist-coating method in the present invention, a chemical is applied on the surface of the substrate while the substrate starts spinning.
According to one embodiment of the photoresist-coating method in the present invention, a chemical is applied on the surface of the substrate after the substrate starts spinning.
According to one embodiment of the photoresist-coating method in the present invention, the said first speed is from about 300 rpm to about 1,500 rpm.
According to one embodiment of the photoresist-coating method in the present invention, the method of coating the photoresist over the surface of the substrate comprises the step of spinning the substrate at a second speed and then applying the photoresist on the surface of the substrate. Wherein, the second speed is higher than the first speed.
Accordingly, in the present invention, a chemical is applied to dampen a substrate while the substrate is kept in a spinning state, before photoresist-coating process. The step can improve the effect of the subsequent photoresist-coating process and avoid possible defects formed during the process. Further, in the present invention, the substrate is kept spinning before the photoresist—is coated thereon, so the gaps or cracks in the formed photoresist layer can be avoided. In short, the present invention can reduce the defects formed during a photoresist-coating process and eventually improve the reliability and yield of semiconductor devices.
The above and other features of the present invention will be better understood from the following detailed description of the embodiments of the invention that is provided in combination with the accompanying drawings.
In semiconductor process, the photoresist technology has been applied broadly. As a result, defects in the formed photoresist layer will have great consequence on the subsequent process and even the integrity of semiconductor devices.
In the present invention, a chemical is applied to dampen a substrate before photoresist is coated on the substrate. Further, when the chemical is applied on the substrate, the substrate is kept in a spinning state. What follows is the description of a photoresist-coating process according to an embodiment of the present invention.
As shown in
Next, with reference to
In addition, in the photoresist-coating method of the present invention, the chemical 108 can be applied on the surface of the substrate 100 while the substrate 100 starts spinning. Further, in the present invention, the chemical 108 can be applied on the surface of the substrate 100 after the substrate starts spinning.
In one embodiment of the present invention, after the step of applying the chemical 108 on the surface of the substrate 100, a spinning step follows, wherein the chemical 108 is spun over the surface of the substrate 100. The timeframe of the spinning stepcan be from about 0.6 seconds to about 2 seconds.
Before the photoresist-coating process, the chemical is applied to dampen the substrate while the substrate is kept spinning, whereby the defects in the formed photoresist layer can be avoided. In addition, the method of dampening the substrate with a chemical while the substrate is kept spinning can not only be applied to photoresist coating, but also to other spin-coating methods in the semiconductor process.
Please refer to
More specifically, the photoresist-coating method of the present invention comprises multiple steps.
As shown in
In addition, after the foregoing steps, step 230 may be performed wherein the chemical is spun over the substrate evenly.
Next, in step 240, the photoresist is coated over the surface of the substrate. The step 240 comprises spinning the substrate (i.e. step 242), and applying the photoresist over the surface of the substrate (i.e. step 244). After step 240, the photoresist-coating process of the present invention is complete.
Accordingly, in the present invention, the substrate starts spinning before the photoresist is coated. Therefore, the method can avoid gaps or cracks in the formed photoresist layer that may trouble the subsequent process and therefore improves the reliability and yield of the semiconductor devices. In addition, in the present invention, a chemical is applied to dampen the substrate while the substrate is kept spinning, before the photoresist-coating process. This method can enhance a desired photoresist-coating and reduce the possible defects in the formed photoresist layer.
To sum up, the present invention has the following advantages:
1. In the present invention, a chemical is applied to dampen a substrate while the substrate is kept in a spinning state, before the photoresist-coating process. The method can prevent defects in the formed photoresist layer during the coating process.
2. The semiconductor manufacturing method in the present invention can prevent gaps or cracks in the formed photoresist layer that may affect the subsequent process and therefore the reliability and yield of semiconductor devices can be improved.
3. The semiconductor manufacturing method in the present invention can be applied not only to photoresist coating, but also to other spin-coating methods in the semiconductor process.
Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be constructed broadly to include other variants and embodiments of the invention which may be made by those skilled in the field of this art without departing from the scope and range of equivalents of the invention.
