Substrate transport apparatus, pod and method

Details Substrate transport apparatus, pod and method Substrate transport apparatus, pod and method

2001-12-04

2004-07-06

Pham, Minh-Chau T. (Department: 1724)

Gas separation

Combined or convertible

Involving communication receiving or transmitting apparatus

C055S385100, C055S385200, C055S418000, C055S471000, C206S710000, C206S711000, C454S187000, C454S192000

Reexamination Certificate

active

06758876

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the structures, capabilities and methods of operating a substrate transport pod suitable for storing or transporting objects such as semiconductor wafers, photo-masks or hard-disks in a highly clean environment, and relates in particular to a method of managing the operation of the substrate transport pod to be used in semiconductor manufacturing processes.
2. Description of the Related Art
As semiconductor elements become more minute, it is anticipated that an even higher degree of cleanliness would be required in the future. For example, it is anticipated that the target control size of the particles that can cause pattern defects and shorting of wiring would become smaller than 0.1 &mgr;m. Further, in addition to particulate contaminants, it becomes necessary to reduce gaseous contaminants. Various hydrocarbon molecules, by adsorbing onto the semiconductor wafers, cause deterioration in voltage resistance of gate oxide film or thickness variations in deposited films. Basic gases react with chemical enhancement type photo-resist to result in loss of resolution, and acidic gases can cause corrosion of wiring.
In addition, moisture (humidity) has been targeted for reduction in recent years. This is because a finer device structure has led to the use of a variety of materials in forming wiring and films, and moisture in the environment can sometimes bind with the above-mentioned materials to cause problems. On the other hand, independent of the trend towards a finer device structure, the size of the wafers is increasing and automation is also progressing in the field of processing technologies. Automation of semiconductor manufacturing lines is prompted by the fact that it is necessary to segregate humans, who act as a contamination source, and the fact that, as the diameter of wafers increases, the weight of the transport pod increases to about 10 kg, such that manual handling becomes difficult.
In the past, with increasing circuit density and speed of semiconductor chips, aluminum has been used as the material for wiring to connect elements within the semiconductor chip. However, when the width of the wires becomes less than 0.13 &mgr;m, conventional aluminum wiring causes serious problems of heat generation and signal delay so that, in place of aluminum wiring, there is a trend towards the use of copper wiring.
Also, SiO
2
has been used as the insulation material for the isolation of wiring. However, the dielectric constant of SiO
2
at about 4 is high so that the replacement of aluminum wiring with copper wiring only results in about a 20% improvement in signal delay, so that there has been a need to use a substance of lower dielectric constant, of less than 3, for the insulation material.
In readying for such a development, the examination of copper wiring and low dielectric materials for insulation has already identified a potential problem, arising from the processing of chips with a line-width at the level of 0.18 &mgr;m. Such low dielectric materials are based on organic materials or porous materials so that problems are such as absorption of moisture from the environment are encountered, which leads to increasing dielectric constants, and therefore, these material must be handled differently from conventional insulation films and are presenting an extremely difficult challenge.
Also, copper used for wiring behaves differently from aluminum that has been used in the past because of its tendency to react with oxygen in the air to produce oxide films. Also, because the copper molecules have higher chemical activity compared with aluminum molecules such that, if particles containing copper or copper vapor itself is discharged into the clean-room, it contaminates the clean-room to lead to severe drop in the yield of semiconductor chips. Also, organic contaminants on a silicon substrate surface have been known to cause a drop in reliability of gate oxide film, an increase in incubation time in the low pressure CVD processes and abnormal film growth. Therefore, even if a superior material is found in the future for use in making low dielectric insulation films, it is conceivable that it cannot be adopted because of its susceptibility to contamination from such impurities as organic substances and ions in the environment. Conversely, by controlling the processing environment, an opportunity may emerge of using those materials that have not been able to be used in the past. Also, if ammonia is present, the photo-resist material applied on the semiconductor wafer exhibits a so-called “T-top” phenomenon, which refers to a phenomenon that the top section of the developed photo-resist is wider than the bottom section.
SUMMARY OF THE INVENTION
The present invention is provided in view of the background information described above, and an object is to provide a substrate transport pod suitable for use in processes for manufacturing semiconductor chips comprised by a combination of copper wiring and low dielectric insulation films having a dielectric constant less than 3, and methods for operating the pod. Also, as the line width becomes finer, problems of contamination resulting from minute quantities of ammonia and organic substances generated from workers and particle contaminants generated from a work uniform, become more serious. Furthermore, due to diversification of customer demands for semiconductor products, it is anticipated that the proportion of “large variety/small quantity” products such as system LSI (large scale integration) circuits will increase in relation to the proportion of “small variety and large quantity” products such as DRAM (dynamic random access memory) and MPU (micro-processor units). For these reasons, there will be a need for facilities that enable varying combinations of semiconductor processing easily and quickly. The present invention provides a substrate transport pod suitable for use in an automated semiconductor processing plant for manufacturing semiconductor devices, including large variety and small quantity products, and methods for operating the pod.
To resolve the problems outlined above, the present invention provides a solution for resolving the problems encountered in semiconductor chip manufacturing processes that utilize copper wiring and insulation films of dielectric constant of less than 3. For example, silicon wafer substrates having low dielectric insulation film, photo-resist film or copper wiring may be housed in a substrate transport pod for transferring or storing the substrates between processes, so that the interior air of the pod is controlled in such a way that the level of at least the moisture is held below a certain value or the ammonia concentration is held below a certain value. Or if copper film is exposed to the interior air of the pod, the level of at least moisture or oxygen concentration is controlled, so that various problems associated with manufacturing semiconductor chips having copper wiring and insulation films of a dielectric constant less than 3 can be resolved. In particular, a structure of the substrate transport pod is provided so as to enable to maintain at least one parameter of the interior air, such as particulate concentration, humidity, organic substance concentration, and ionic gas concentration, to a level below a specific value. Further, a method of operating a plurality of substrate transport pods in an automated semiconductor manufacturing plant is provided.
As explained above, the present invention relates to the structure and capabilities as well as a method of using a substrate transport pod suitable for use in storing or transporting an object to be subjected to processing, such as semiconductor wafers, photo-masks or hard disks, under a highly clean atmosphere. Therefore, it is applicable to manufacturing of semiconductor devices based on highly conductive wiring, such as copper wiring, and insulation films having a low dielectric constant.


REFERENCES:
patent: 4471716 (1984-09-01), Milliren
patent

Affiliated with

Also associated with

Rating

Substrate transport apparatus, pod and method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Substrate transport apparatus, pod and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Substrate transport apparatus, pod and method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3228129