JPH07191732A - Method and device for deciding process specification in production process of product - Google Patents

Abstract

PURPOSE:To maximize nondefective product productivity by quantitatively evalulating both the yield improving effect by the maintenance of a producing equipment and the lowering of productivity caused by downtime to decide the particle control specs of a process. CONSTITUTION:This device is provided with a no.1 storage part 1 previously storing a first relation expressing the corresponding relation between the generation amount of particles generated at the production process of the product and the nondefective product rate of the product, which is hindered by the particles. Furthermore, the device is provided with a no.2 storage part 2 previously storing a second relation expressing the corresponding relation between the frequency of the maintenance of the production process for reducing the particles and the production amount of the product. Then, an evaluation function arithmetic part 3 calculates an evaluation function for the productivity evaluation of the production process through the use of the first and second relations stored in the respective no.1 and 2 storage parts 1 and 2. Next, a process specs deciding part 4 decides the process specs being the allowable value of the particles in the production process based on the evaluation function calculated by the evaluation function arithmetic part 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process specification determining method and apparatus in a product manufacturing process, and more particularly to a process specification determining method and apparatus in a product manufacturing process such as ultra-precision machines and integrated circuits. is there.

[0002]

2. Description of the Related Art Generally, when manufacturing a product, the process specification in the manufacturing process of the product is to consider the known allowable values such as processing dimensions and processing temperature in the design stage which is a stage before manufacturing the product. After that, it will be tentatively decided from the top down. This tentative process specification is a theoretical theoretically calculated value. Next, based on this trial calculation value, it is actually verified by experiments whether a good product can be manufactured. If the verification result is negative, the human repeats the procedure of correcting and re-verifying the temporary process specifications. Then, if it is possible to verify that a non-defective product can be manufactured, the above-mentioned temporary process specifications become regular process specifications in the manufacturing process. Conventionally, as described above, a process specification determination method has been used in which a process specification is first provisionally determined based on a known allowable value required on a desk and its validity is examined.

[0003]

The above-described conventional process specification determining method in the manufacturing process of products has the following problems. In the manufacture of precision machines such as new ultra-precision machines and integrated circuits, HDDs (hard disk drives), liquid crystal displays, CCDs (charge coupled devices), and electronic parts that have rapidly developed in recent years, they float in manufacturing equipment. It has been found that particles (dust) adhere to the product being manufactured, thereby reducing the yield rate of the product. In order to reduce the particles floating in the manufacturing apparatus, it is necessary to suspend the operation of the manufacturing apparatus in operation and manually clean the apparatus. This work improves the yield rate of products, but on the other hand reduces the operating rate of manufacturing equipment, resulting in
Reduce the production of products. At present, it is possible to measure the amount of particles floating in the manufacturing equipment attached to the product, but to what extent can the particles be reduced?
It is not well known whether it is sufficient to produce a good product, and how appropriate the maintenance work frequency is from the viewpoint of minimizing the production volume. For this reason, the conventional process specification determination method cannot determine the specification regarding the adhesion of particles to the product, and the control thereof cannot be sufficiently performed. The present invention is designed to maximize the productivity of non-defective products in the entire manufacturing device in consideration of both the improvement of the non-defective product rate (yield) due to the maintenance of the manufacturing device and the decrease in productivity due to downtime due to the maintenance. An object of the present invention is to provide a process specification determining method and apparatus in a manufacturing process of a product capable of determining a particle management specification of a process.

[0004]

In order to achieve the above-mentioned object, the present invention provides a first relation representing the correspondence between the amount of particles generated in the manufacturing process of a product and the yield of the product which is hindered by the particles. And the second relationship representing the correspondence relationship between the maintenance frequency of the manufacturing process for reducing the particles and the production amount of the product are stored in advance, and the stored first and second relationships are stored. The evaluation function for evaluating the productivity of the manufacturing process is calculated using the relationship of, and the process specification, which is the allowable value of the amount of particles generated in the manufacturing process, is determined based on the calculated evaluation function. It is configured as a process specification determination method in the manufacturing process of the following products. In addition, a first storage unit that stores in advance a first relationship that represents a correspondence relationship between the amount of particles generated in the manufacturing process of the product and the yield of the product that is hindered by the particles; Second storage means for storing in advance a second relationship representing a correspondence relationship between the frequency of maintenance of the manufacturing process for reducing and the production amount of the product;
The first and the first stored in the first and second storage means, respectively.
Generation of particles in the manufacturing process based on an evaluation function calculating unit that calculates an evaluation function for evaluating the productivity of the manufacturing process using the second relationship, and the evaluation function calculated by the evaluation function calculating unit. A process specification determining device in a manufacturing process of a product, comprising: a process specification determining unit that determines a process specification that is an allowable value of quantity.

[0005]

According to the present invention, the first relationship showing the correspondence relationship between the amount of particles generated in the manufacturing process of a product and the yield of the product hindered by the particles, and the above-mentioned relationship for reducing the particles A second relationship representing a correspondence relationship between the maintenance frequency of the manufacturing process and the production amount of the product is stored in advance. The first stored above
An evaluation function for evaluating the productivity of the manufacturing process is calculated using the second relationship. Based on the calculated evaluation function, a process specification that is an allowable value of the amount of particles generated in the manufacturing process is determined. in this way,
Manufacturing that maximizes the productivity of non-defective products in the entire manufacturing equipment by quantitatively evaluating both the yield improvement effect due to the maintenance of the manufacturing equipment and the decrease in productivity due to downtime due to the maintenance. It is possible to determine the particle management specifications of the process.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the accompanying drawings for the understanding of the present invention. The following embodiments are examples of embodying the present invention and are not intended to limit the technical scope of the present invention. 1 is a diagram showing a schematic flow of a process specification determining method according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a schematic configuration of an apparatus A to which the process specification determining method can be applied.
3 is a diagram showing the relationship between the cumulative use time of the device and the number of particles generated, FIG. 4 is a diagram showing the relationship between the number of particles generated and the maintenance frequency, and FIG. 5 is a relationship between the maintenance frequency and the production amount (trial calculation value). 6 is a diagram showing the relationship between the number of particles generated and the non-defective product rate (trial calculation value), and FIG. 7 is a diagram showing the relationship between the number of particles generated and the non-defective product rate / production amount. As shown in FIG. 1, the process specification determining method in the manufacturing process of the product according to the present embodiment has a correspondence relationship between the generation amount of particles generated in the manufacturing process of the product and the non-defective rate (yield) of the product which is obstructed by the particles. First representing
And a second relationship representing a correspondence relationship between the maintenance frequency of the manufacturing process for reducing particles and the production amount of the product are stored in advance (S1), and the stored first and second relationships are stored. An evaluation function for evaluating the productivity of the manufacturing process is calculated using the relationship (S2), and the process specification, which is the allowable value of the amount of particles generated in the manufacturing process, is determined based on the calculated evaluation function. It is configured. The basic principle of this method will be described below. In order to determine the device management specification of particles, that is, how much particles should be reduced to produce a good product, necessary information may be acquired by the following procedure. The relation between the maintenance frequency of the manufacturing apparatus in a certain arbitrary process, that is, the ratio of the time related to maintenance to the operating time, and the particle generation amount of the manufacturing apparatus is experimentally obtained, and the actual case is inferred from this. Let i be an arbitrary device, Xi be the maintenance frequency of the device i, and Pi be the particle generation amount. Here, since the relationship between the maintenance frequency Xi and the particle generation amount Pi is 1: 1, the experimental result is approximated and expressed as mathematical expression Xi = fi (Pi). As an approximation method, for example, the least squares method may be used (the same applies below). The amount of particles floating in the air in the manufacturing apparatus can be measured by a particle measuring device (not shown) such as a commercially available laser particle counter.

Next, the production amount of products per unit time (including defective products) is expressed as S. Since the production amount S is the amount that increases or decreases depending on the value of the maintenance frequency Xi, this relation (corresponding to the second relation) is trial calculated and the relational expression S
= S (Xi) is calculated. This relational expression may be a mathematical expression approximated from the data. Next, the good product rate of the product is expressed as R, and the relationship (corresponding to the first relationship) between the good product rate R and the particle generation amount Pi in the manufacturing apparatus is investigated and analyzed.
We ask experimentally. The relational expression R = r (Pi) is obtained by approximating the experimental data. In the investigation and analysis, the particles that actually adhere to the product being manufactured in an arbitrary process are found by a microscope or similar observation device, and the rate of causing defects is determined from the observation results of how the particles adhere to the product. Furthermore, the product yield is predicted and calculated from this result. Here, consider the case where the specification is determined by this method over the entire manufacturing process of the product. A manufacturing process consists of multiple processes, and one process is often related to another process. In some cases, the particles attached to the product in the previous process are removed in the next process, and the problem may disappear. In such a case, the process in which particles adhere to the product and the particle removal process in the next process are integrated, and (number of particles generated) x (particle removal efficiency in the next process) is the amount of particles generated in that process. It may be Pi. To further explain, in order to obtain the probability that particles attached to the product in the process of interest cause defects, the amount of particles generated in the equipment is changed experimentally to force the particles to adhere to the product, The relationship between the adhesion amount and the actual yield may be investigated.

As described above, the following relational expressions were derived. Xi = fi (Pi) (1) S = s (Xi) (2) R = r (Pi) (3) By substituting the equation (1) into the equation (2), the production amount ( S (including defective products) can be expressed as a relational expression of the particle generation amount Pi of the manufacturing apparatus. S = s (fi (Pi)) (4) As the production amount of non-defective products per unit time, the above (3),
The following equation is derived from the equation (4). S × R = s (fi (Pi)) × r (Pi) (5) The above equation (5) represents the production amount of the non-defective product per unit time, and is a parameter (in the evaluation function) that represents the productivity (production efficiency). Equivalent). Therefore, the particle generation amount Pi that maximizes the value of the parameter S × R is obtained from the above equation (5), and this may be set as the optimum particle allowable value of the apparatus i. The method thus proceeds in any device i
By using the particle generation amount Pi of 1 as a variable and deriving a relational expression that describes the non-defective rate and the productivity of the product, it is possible to obtain the process specification that is the optimum allowable value of the particles. Subsequently, in order to further embody the above-described process specification determination method, an apparatus A to which the method can be applied will be described.

As shown in FIG. 2, the process specification determining apparatus A in the manufacturing process of the product according to the present embodiment mainly includes the generation amount of particles generated in the manufacturing process of the product and the non-defective rate of the product (). Yield)
The first relationship representing the correspondence relationship with
o. No. 1 storing unit 1 (corresponding to the first storing unit) and a second relation indicating the correspondence relation between the maintenance frequency of the manufacturing process for reducing particles and the production amount of the product are stored in advance. 2 storage unit 2 (corresponding to second storage means)
And No. An evaluation function calculation unit 3 (corresponding to evaluation function calculation means) that calculates an evaluation function for evaluating the productivity of the manufacturing process using the first and second relationships stored in the storage units 1 and 2, respectively. ) And a process spec determining unit 4 (corresponding to a process spec determining unit) that determines a process spec that is an allowable value of the amount of particles generated in the manufacturing process based on the evaluation function calculated by the evaluation function calculator 3. Each component is constructed as a process on software of a computer (not shown), for example. In addition, the present device A uses the No. 1 and No. 2 relationships described above as an auxiliary device. 1, 2 are provided with an input unit 0 such as a keyboard and a display for inputting to the storage units 1 and 2, and an output unit 5 such as a printer for outputting the result from the process specification determination unit 4. Therefore, in the present apparatus A, among the steps in the method of determining the process specification, No.
1 storage unit 1 and No. 1 2 The storage unit 2 executes step S1,
The evaluation function calculation unit 3 executes step S2, and the process specification determination unit 4 executes step S3. Hereinafter, a specific operation example of the device A will be described. That is, this device A
Thus, the particle management specifications of the manufacturing apparatus used in the film forming process, which is one of the manufacturing processes of the thin film magnetic head used for HDD (hard disk drive), are determined. Here, an explanation will be given based on the data obtained when a thin film magnetic head was actually prototyped in the laboratory.

First, an experimental apparatus as a target for determining specifications is a sputtering film forming apparatus (i = 1) here.
And The number of particles generated after the maintenance (device cleaning) of the film forming apparatus is checked. The number P1 of particles generated was examined using a commercially available laser particle counter. The result is shown in FIG. From the figure, it can be seen that the number P1 of particles generated increases with the increase in the cumulative use time of the apparatus. Next, considering the work time spent for maintenance, the content of FIG.
4 was obtained by converting the relationship between the maintenance frequency X1 and the maintenance frequency X1. In addition, here, maintenance frequency =
(Time required for device cleaning) × number of times / (device operating time), and by substituting into equation (1) the time required for one maintenance is 1 hour and the device operating time is 10 hours. Calculate the following formula. X1 = f1 (P1) = 60 / P1 (1 ') Next, the production amount per unit time (including process defective products) S
And the maintenance frequency X1 (corresponding to the second relationship) were calculated by trial calculation and shown in FIG. By substituting this into the equation (2), the following approximate equation is derived. S = s (X1) = 10 / X1 (2 ') The operator uses the input unit 0 to input the equation (2') showing the relationship between the production amount S (including defective products) and the maintenance frequency X1. No. 2 Input to the storage unit 2. Next, by investigating and analyzing the relationship (corresponding to the first relationship) between the product non-defective rate R and the particle generation number P1 of the film forming apparatus,
The result obtained experimentally is shown in FIG. The following approximate expression is derived by substituting this into the expression (3). R = r (P1) = − 0.0035 × P1 + 1.75 (3 ′) In the investigation / analysis, the particles adhering to the product in an actual arbitrary process are found by a microscope or similar observation device, and the product of the particle is obtained. The rate of causing defects was determined from the state of adhesion to the. The operator represents the relationship between the non-defective product rate R and the particle generation amount P1 (3 ').
No. is calculated using the input unit 0. 1 Input to the storage unit 1.

After the above work is completed, the evaluation function operation unit 3 is operated by the operator's instruction. The following calculation is performed based on the contents stored in the storage units 1 and 2. By substituting the equation (1 ′) into the equation (2 ′), the production amount (including defective products) S can be expressed as a relational expression of the particle generation number P1 of the experimental apparatus. S = s (f1 (P1)) = 10 / X1 = 10 / (60 / P1) = P1 / 6 (4 ') The production amount of non-defective products per unit time is calculated by the parameter S × R.
(Corresponding to the evaluation function), the above (3 '),
The following equation is derived from the equation (4 '). The evaluation function calculator 3 calculates the parameter S × R using this relational expression. S × R = s (f1 (P1)) × r (P1) = (P1 × 1/6) × (−0.0035 × P1 + 1.75) = − 0.00058 × P1 ² + 0.29 × P1 ... ( 5 ') This relational expression is shown in FIG. From the figure, the parameter S × R
The maximum value of is when the number of generated particles P1 = 250, and the parameter S × R is 36.25 at this time. Therefore, in this case, the optimum particle management specification of this film forming apparatus, that is, the process specification Pa is 2
50 or less. The process specification calculation unit 4 determines the process specification Pa and outputs the result from the output unit 5. From the above, the following can be said. Conventionally, it is possible to measure the amount of particles (dust) floating in the manufacturing equipment attached to the product, but to what extent can the particles be reduced to produce good products?
In addition, it was not clear how appropriate the maintenance work frequency was from the viewpoint of minimizing productivity. However, according to the method (apparatus A) of the present embodiment, it is possible to quantitatively evaluate both the effect of improving the non-defective product rate (yield) due to the maintenance of the manufacturing apparatus and the decrease in productivity due to downtime due to the maintenance.

As a result, it is possible to obtain a process specification determining method and apparatus in a product manufacturing process that can determine particle management specifications of a manufacturing process that maximizes the productivity of non-defective products in the entire manufacturing apparatus. By the way, the device A of the above-mentioned embodiment is the most basic one, and it is assumed that a human previously obtains the respective relational expressions (1 ′) to (3 ′). Can be easily included. Specifically, for example, the evaluation function calculation unit 3
The derivation procedure may be incorporated in advance. In that case,
The input data is only basic data such as particle generation amount Pi, maintenance frequency Xi, production amount (including process defective products) S, etc., and since it is automatically calculated after that, process specifications can be determined at high speed and with high reliability. be able to.
In the device A of the above embodiment, it is assumed that each component is constructed as, for example, each process in software of a computer, but in actual use, all or part of them is configured by hardware. However, there is no problem.
Incidentally, in the operation example of the apparatus A of the above-mentioned embodiment, the sputter film forming apparatus has been described, but in actual use, it can be applied to any other manufacturing apparatus used for manufacturing ultra-precision machines or integrated circuits.

[0013]

Since the method and apparatus for determining the process specifications in the manufacturing process of the product according to the present invention are configured as described above, the effect of improving the yield due to the maintenance of the manufacturing device and the production accompanying the downtime due to the maintenance. Both the decrease in sex can be quantitatively evaluated. As a result, it is possible to obtain a process specification determining method and apparatus in a product manufacturing process that can determine particle management specifications in the manufacturing process that maximize the productivity of non-defective products in the entire manufacturing apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic flow of a process specification determining method according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an apparatus A to which the method for determining process specifications can be applied.

FIG. 3 is a diagram showing a relationship between a cumulative use time of the apparatus and the number of particles generated.

FIG. 4 is a diagram showing the relationship between the number of particles generated and the maintenance frequency.

FIG. 5 is a diagram showing a relationship between a maintenance frequency and a production amount (trial calculation value).

FIG. 6 is a diagram showing the relationship between the number of particles generated and the yield rate (trial calculation value).

FIG. 7 is a diagram showing the relationship between the number of particles generated and the yield rate / production rate.

[Explanation of symbols]

A ... Process spec determination device 1 ... No. 1 storage unit (corresponding to a first storage unit) 2 ... No. 2 storage unit (corresponding to second storage unit) 3 ... evaluation function computing unit (corresponding to evaluation function computing unit) 4 ... process spec determining unit (corresponding to process spec determining unit)

Claims (2)

[Claims] 1. A first relationship representing a correspondence relationship between an amount of particles generated in a manufacturing process of a product and a yield of the product which is hindered by the particles, and a manufacturing process of the manufacturing process for reducing the particles. A second relationship indicating the correspondence relationship between the maintenance frequency and the production amount of the product is stored in advance, and the productivity of the manufacturing process is evaluated using the stored first and second relationships. Is calculated, and a process specification which is an allowable value of the amount of particles generated in the manufacturing process is determined based on the calculated evaluation function. 2. A first storage means for storing in advance a first relationship representing a correspondence relationship between an amount of particles generated in a manufacturing process of a product and a yield of the product which is hindered by the particles. A second storage unit that stores in advance a second relationship indicating a correspondence relationship between the maintenance frequency of the manufacturing process for reducing the particles and the production amount of the product, and the first and second storage units. Evaluation function calculation means for calculating an evaluation function for evaluating the productivity of the manufacturing process using the first and second relationships stored in the storage means, and the evaluation function calculated by the evaluation function calculation means. And a process specification determining means for determining a process specification that is an allowable value of the amount of particles generated in the manufacturing process based on .