Visualizing methods for dispatch and diagnosis of finite...

Details Visualizing methods for dispatch and diagnosis of finite... Visualizing methods for dispatch and diagnosis of finite...

1998-04-21

2001-05-08

Sheikh, Ayaz R. (Department: 2781)

Data processing: generic control systems or specific application

Specific application, apparatus or process

Product assembly or manufacturing

C700S095000, C700S900000, C700S100000, C700S102000, C700S117000, C379S010030, C379S014000, C379S015050, C379S030000, C438S149000, C438S166000, C438S486000, C438S693000

Reexamination Certificate

active

06230068

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method of dispatching for the semiconductor's manufacturing machines, and more specifically, to a method of visualizing the working condition of the semiconductor's manufacturing machines.
BACKGROUND OF THE INVENTION
In the semiconductor's manufacturing, hundreds of processing steps are needed for a semiconductor device. A product travels through different types of stages in a processing line, and a product has different processing time in every stage. For example, diffusion stage and implanting stage have long processing time (4-12 hours). The long-time stages are the bottlenecks of the processing line in a FAB. Also, a specified amount of wafers are put into the processing line everyday, but the processing speed of these wafers will be slow down in these long-time stages. When the tool's capacities of the processing line is reduced, the throughput of the processing line is reduced, too. The above condition reduces the efficiency of the machines in the FAB and increases the cost of the production in the semiconductor manufacturing. Thus, the goal to perform continuous production is important, and performing the dispatching is a great challenge in order to make sure the stability of the throughput of the processing line.
To make sure the production running continuously within finite tools, controlling the number of wafer-in-process (WIP) and the number of wafers to be put in the processing is important. In the prior art, using the key-stage report (KSR) of a processing line is a usual method to understand the working condition of the machines in the processing line. In the KSR, several parameters of the processing line are recorded. These parameters include the quantities of wafers which are in the preprocess of a stage, in the process of a stage and at the end of a stage.
TABLE 1:
TURN
STAGE_ID
WIP
OUT
PRE
MAIN
MRUN
AFTER
RATIO
WAF-START
312
528
0
240
72
0
1.7
SIN-1-PHO
48
0
0
48
0
0
0
WELL-OX
0
14
0
0
0
0
0
WELL-PHO
444
252
0
348
96
0
0.6
WELL-ETCH
0
0
0
0
0
0
0
N-WL-2-IMP
270
522
0
174
0
96
1.9
PWELL-PHO
248
372
0
104
144
0
1.5
P-WL-2-IMP
210
720
0
114
48
48
3.4
WELL-DRIV
2281
736
1116
48
1116
1
0.3
As be shown in TABLE 1, a part of key-stage report is shown in this table. The sequence of the processes in this report is according to the production flow of a product in a FAB. For example, the third stage to the fifth stage of TABLE 1 are the formation of a well region. The stages are the oxide deposition of the well region, the lithography of the well region and the etching of the well region. These stages form a process chain. According to the report, supervisors of the production line can realize the working condition of the production line. In the following description, the datas of the report are explained. ‘OUT’ in this report means the counts of the wafers of which are from this stage to the next stage. ‘MAIN’ means the counts of wafers which are waiting for tools. ‘MRUN’ means the counts of wafers, which are processed by the tools in this stage. ‘PRE’ means the counts of wafers, which need preprocess for this stage, such as hot plate, B Clean etc. ‘After’ is the wafer at the end of this stage, such as the inspecting process. Supervisors realizes one stage in the process flow, for example, a lithography stage, by checking the quantities of the stage. As result of the invariable quality of the same type of equipments in a FAB, the equipments must have good allocation to every stages to make sure of the normality of the processing line.
One characteristic of the semiconductor's manufacturing in a processing line is the operational flows, which are repeated by tool (tool group) or area. Based on this fact, supervisor who takes care of some areas and tools must keep on watching the KSR. For example, in Table 2, the supervisor in the photo area must arrange the tools in photo stage well-etching process (WELL-ETCH), well high-energy implantation process (H-WL-2-IMP), P-type well implantation process (P-WL-2-IMP), second nitiride oxide etching process (SIN-2-OXET), second nitride etching process (SIN-2-ETCH) and P-type field region implantation process (P_FLD_IMP). The relationship of these stages is as below.
TABLE 2
Supplied Stage
Reguested stage
WELL-PHO
WELL-ETCH
H-WL-2-IMP
PWELL-PHO
P-WL-2-IMP
SIN-2-PHO
SIN2-OXET
SIN-2-ETCH
P_FLD_PHO
P_FLD_IMP
In TABLE 2, the relationship between the supplied stages and the requested stages has many different types. After products have been through the process of the supplied stage, the products of the supplied stages then move to the requested stages. For example, the products after some photolithography's process can be moved to etching stages or implanting stages, the products after other photolithography's process could only be moved to implanting stages. The allocation of the photolithography's tools in a processing line can be changed. In other words, the requested stages have many different stages and the supplied stages have many different stages, too. Besides, the supervisors of a processing line must decide the allocation of the equipments in the supplied stage and solve the bottleneck problem of the processing line.
Supervisors read the KSR of the processing line in order to realize the working condition of the stages in the processing line and then decide the dispatching of the tools in the processing line. Currently, stage number of the photolithography in a production's flow is about twenty to thirty. The total number of the parameters in the production's flow is about two hundreds to three hundreds. The length of the report is between five to seven pages and the datas of the report is a fifth multiple of the datas of the TABLE 1. Controlling the status of photolithography's tools is a difficult job for the supervisors of the tools. Arranging the tool's capacity of the photo area to provide sufficient supply for every requested stage is a very important topic. However, the supervisor of the photo area can not make decision easily to perform dispatching for the finite tool's capacities from KSR or other report. In other words, the supervisors can not make a good dispatch for lack of powerful tools.
SUMMARY OF THE INVENTION
A visualizing method for the working condition of the semiconductor's manufacturing machines is disclosed in the present invention. The method is described in the following description. Firstly, the data of stages in a processing line are collected from the key-stage report of the processing line. The datas are “MAIN”, “MRUN”, “AFTER” and “PRE”. Specified stage-pairs in the processing line are determined. These pairs comprise photolithography and etching, photolithography and implanting etc. The data of each stage-pair is sequentially arranged and is put into a bar chart. One pair has a supplied stage and a requested stage. From the bar chart, supervisors of the processing line can understand the working condition and the priority of every stage. Thus, the supervisors can decide the allocation of the tools in the processing line.


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