The present invention relates to an apparatus for wafer treatment for the manufacture of semiconductor devices. More particularly, the present invention relates to an apparatus for wafer treatment for improving the process uniformity of a specific semiconductor device fabrication process, such as an etching or a cleaning, by minimizing the temperature changes of the treatment solution supplied on the wafer mounted on a spin chuck.
Generally, the process of manufacturing semiconductor devices involves a wide variety of steps including a layer formation process for forming multiple layers such as a polycrystalline layer, an oxide layer, a nitride layer, a metal layer, etc. on a wafer as a semiconductor substrate. These steps generally also include a diffusion process, a photolithography process, an etching process, a cleaning process, an ion implantation process, and the like, which are carried out between the steps of layer formation.
Among the process steps for manufacturing semiconductor devices, a wafer treatment process such as etching and cleaning processes, etc. may employ an apparatus for wafer treatment including a spin chuck used to rotate the wafer when it is mounted on the spin chuck.
In the above wafer treatment process using the apparatus for wafer treatment, the wafer is mounted on the spin chuck, and is rotated along with the rotating spin chuck. A specific process is then carried out for the wafer, such as etching some portion of the layers formed on the wafer or removing the particles existing on the wafer by supplying a respective treatment solution corresponding to the specific process. In either case, the process uses the centrifugal force of the rotating spin chuck and the pressure of the pressurized treatment solution when it is supplied to accomplish these goals.
Important process factors in the wafer treatment process include the rotation speed of the spin chuck, the kinds of the treatment solutions used for the wafer, the process temperature of the treatment solution, and the like. For example, the wafer treatment solution should be maintained at a temperature higher than room temperature when it is used in order to facilitate the reaction rate of the treated subject and the treatment solution in the aspect of the mass production of semiconductor devices and the reduction of the treatment time.
However, the actual process environment of the treatment process cannot completely satisfy these conditions. For example, when a treatment solution having a temperature of about 100.degree. C. is supplied on the wafer rotating on the spin chuck, the treatment solution cannot maintain its original temperature of 100.degree. C. due to the temperature difference between the treatment solution and the wafer. In other words, a temperature difference occurs when the treatment solution is initially contacted with the wafer, and as it moves to the peripheral edge of the wafer by the centrifugal force from the rotation of the spin chuck. The treatment solution has temperature higher than room temperature when it is initially supplied on the wafer, but its temperature changes, i.e., cools, as it contacts the wafer and moves along the surface of the wafer. Furthermore, the larger the diameter of wafer processed, the more and greater the temperature difference will be. This is particularly true for large wafers, such as those as large as 12 inches or more in diameter.
The temperature variation in the treatment solution as the process progresses causes a difference in the reaction rate of the treatment solution on respective portions of the wafer. This results in the deterioration of the uniformity of the treatment process itself, and disrupts the etching uniformity or cleaning uniformity of the wafer. These deteriorated uniformity problems are more serious in an etching process forming the contact hole plugs of a conductive material by a spin-etching method.
The higher integration of semiconductor devices that is increasingly needed requires a more precise etching process and cleaning process. As a result, it becomes necessary to increase the accuracy of spin etching processes.