RU2801320C2 - Method and unit for semiconductor manufacture - Google Patents

Abstract

FIELD: semiconductors.

SUBSTANCE: present invention relates to washing procedures in the production of semiconductors. The ultrapure water supply unit (50) comprises an ultrapure water production unit (54), a supply pipeline (52), an operation control unit (53), and an ultrapure water injection unit (55). The first end of the supply pipeline (52) is connected to the outlet of the ultrapure water production unit (54). The second end of the supply pipeline is configured to be connected to the semiconductor washing device. The operation control unit (53) is configured to control the ultrapure water production unit (54) to produce a predetermined amount of ultrapure water upon request. The injection unit (55) for ultrapure water has access to a source of inert gas and is configured to clean the supply pipeline (52) from water with inert gas after supplying a predetermined amount of ultrapure water. A semiconductor washing system, a semiconductor manufacturing system, and a method for supplying washing water are also disclosed.

EFFECT: increasing the purity of ultrapure water by reducing the time during which ultrapure water is in contact with elements other than the objects to be cleaned.

13 cl, 4 dwg

Description

The field of technology to which the invention belongs

The present invention relates generally to the production of semiconductors, and in particular to flushing procedures in a semiconductor manufacturing process.

State of the art

The quality of semiconductor products is highly dependent on the purity of the manufacturing process. Currently, the production of semiconductor wafers is usually carried out on a production line located at least partially within a clean zone. The importance of cleanliness conditions in the manufacturing process increases as the line width of the components of the semiconductor products being produced decreases.

In the production of electronic components today, the general trend is the production of electronic circuits with ever smaller line widths. Currently, some electronics manufacturers offer commercially available nanochips with linewidths around 400 nm. However, even smaller linewidths, down to 10 or even 5 nm, are considered in research projects. Thus, among many users of small electronic circuits, there is a demand for chips with linewidths up to 10 or 5 nm, which would be available as commercial products.

However, there is always a significant gap between research results and an available commercial product. The procedures used in research and development are not always suitable for direct implementation in large-scale production.

A production line may contain 50 or even up to 100 process steps. The particles that come into contact with the chip during the manufacturing process are one of the limiting factors for the production of electronics with small line widths. To do this, the entire production line is usually kept in ultra-clean conditions with reduced human contact as much as possible. Chip cleaning is necessary between certain process steps, for example to remove excess chemicals from a previous process step or particles.

Typically, the ultrapure water production unit (UPW) produces ultrapure water and stores it in a tank. At each stage of cleaning, it is allowed to flush the chip with this UPW to remove chemicals and particles.

US Patent Publication US 6,461,519 B1 discloses a process for producing ultrapure water for semiconductor manufacturing. In the first stage of treatment, raw water, such as tap water or spring water, is pre-treated to achieve a certain level of purity. The final processing step is decentralized, with a corresponding final cleaning unit provided in the service area in close proximity to the clean area of each production unit. This final cleaning section allows low cost piping from the primary processing unit to the respective finishing units. The short distance between each finishing unit and the corresponding production unit uses high quality piping that contributes less to pollution.

Such approaches provide an additional increase in the purity of the wash water. However, maintaining low-polluting feed lines still contributes to contamination, and any storage of ultrapure water in tanks and/or lines while waiting for the next flushing step still results in increased contamination.

Disclosure of invention

The overall goal is to provide methods and devices for improving the purity of ultrapure water for semiconductor production.

The above problem is solved by methods and devices in accordance with the independent claims. Preferred embodiments are defined in the dependent claims.

One advantage of the proposed technology is that it increases the purity of the ultrapure water supplied to the washing step in a semiconductor production line. Other advantages will become clear upon reading the detailed description.

Brief description of the drawings

The invention, together with its additional objects and advantages, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 schematically illustrates an embodiment of a semiconductor manufacturing system;

Fig. 2 illustrates an embodiment of a semiconductor manufacturing site;

Fig. 3 illustrates a block diagram of the steps of an embodiment of the wash water supply method; And

Fig. 4 illustrates a schematic drawing of an embodiment of an installation for supplying wash water.

Implementation of the invention

Throughout the drawings, like or corresponding elements use the same reference numerals.

Ultrapure water has interesting properties that can be used for purification purposes. Due to the small amount of dissolved substances, well below their levels in drinking water, ultrapure water has a strong affinity for almost any substance. The use of ultrapure water as a flushing liquid in a semiconductor production line is thus highly beneficial and has been known per se for many years. The absence of particles also becomes important in the production of nanochips, since the remains of particles from the washing liquid can disrupt the geometric structures obtained during the production process.

Due to its high affinity for contamination, ultrapure water also dissolves substances during storage and transport. Considerable efforts are made to minimize storage time and transport distances between the ultrapure water production unit and the rinsing steps in a semiconductor production line. Pipelines and storage tanks are used, lined with a material that withstands ultrapure water to some extent. However, such materials are expensive and do not completely eliminate contamination. When the line widths of manufactured chips reach several nanometers, the quality of the water used for rinsing between different stages of production presents an even more difficult problem.

The dissolution of substances in ultrapure water not only depends on the surrounding material, but also depends on the contact time, i.e. the length of time ultrapure water can act to dissolve substances. Thus, all kinds of storage tanks are undesirable. In addition, long transport pipelines also increase the exposure time to ultrapure water.

Thus, the technology presented herein aims to reduce the time that ultrapure water is in contact with elements other than the objects to be treated.

Fig. 1 schematically illustrates an embodiment of a semiconductor manufacturing system 1 having a line of semiconductor manufacturing sites 10 contained in a clean zone 20. The line includes at least one semiconductor manufacturing site 10, but typically contains a plurality, such as 50-100 sites. The service area 25 is located along the clean area and connected to it to provide necessary services that cannot be located in the clean area, or at least are unnecessary there.

At least one of the semiconductor manufacturing sites 10, and typically a plurality of sites, comprises a semiconductor washing system 30 having a semiconductor washing device 40 and a washing water supply facility 50 . The semiconductor washer 40 washes the semiconductor elements by immersion, agitation, or centrifugation, or a combination thereof, and is operated manually or automatically. In the installation 50 for supplying wash water, water is supplied from the service area 25 through the pipeline 51 water supply. The water supplied by the water supply line 51 is pure but not ultrapure, and is usually ordinary tap water.

In prior art systems, on the other hand, the production of ultrapure water is usually provided in the service area, and then the ultrapure water is transported to the clean area by means of supply pipelines.

By locating the flush water supply unit 50 in the clean zone 20, the supply line 52 connecting the rinse water supply unit 50 to the semiconductor washer 40 can be made very short. The current state of the art in flush water supply systems makes it possible to operate in a clean area. During the production of ultrapure water, a certain amount of heat is dissipated in the volume surrounding the production unit. For large production units, such as those currently used in the service area, the amount of heat generated can be a problem if large production units are moved to a clean area. However, for small local ultrapure water production units distributed along the entire production line, heat generation is usually acceptable even without specific chillers.

The semiconductor manufacturing system 1, of course, contains many other functional elements, both in the clean zone 20 and in the service zone 25. However, such functional elements themselves are well known in the art and are not essential to the technology presented in this document. , and therefore they are not considered in the present description.

Fig. 2 illustrates an embodiment of a semiconductor manufacturing site 10 in more detail. The semiconductor manufacturing section 10 includes a process unit 11 configured to perform a process step in the semiconductor manufacturing process. The semiconductor elements are introduced into the process block 11 through the inlet 12, either as raw material or from a previous step. The semiconductor elements are processed in the process unit 11 according to processes which are known per se from the prior art. When the process is completed and the processed semiconductor elements are to be washed, the semiconductor elements are transferred to the semiconductor washing device 40 of the semiconductor washing system 30 via connection 13.

Alternatively, the process unit 11 and the semiconductor washer 40 may be combined into one common unit.

The washing process in the semiconductor washing device 40 requires a certain amount of ultrapure water. This amount is usually determined in connection with the installation of the pipeline, for example by controlling the flow rate in relation to the amount of ultrapure water. This specific required amount of ultrapure water can also be updated later in different situations during the production processes.

When the semiconductor elements to be processed are ready for washing, a request is sent to the washing water supply unit 50 to supply ultrapure water to the semiconductor washing device 40 in a predetermined amount corresponding to the needs of the semiconductor washing device 40 . This feeding operation will be discussed further below in more detail.

When the washing process is completed, the washed semiconductor elements are discharged through the outlet 14 to the next semiconductor production area 10 or as a finished product.

Fig. 3 illustrates a block diagram of the steps of an embodiment of the wash water supply method. In step S2, the wash water supply unit receives a request to supply a predetermined amount of ultrapure water. In step S4, a predetermined amount of ultrapure water is produced. Thus, this production is carried out only on request. In step S6, in direct connection with said production, a predetermined amount of ultrapure water is supplied to the semiconductor washing device through the supply pipeline. There is usually some residual ultrapure water left in the supply line when the supply is being made. If this ultrapure water is allowed to remain in the supply line for an interval until the next supply event, the ultrapure water can be heavily contaminated. Therefore, in step S8, the supply line is purged of water. This purification is carried out by means of an inert gas after, and preferably immediately after, the supply of a predetermined amount of ultrapure water through the supply line. Thus, no ultrapure water remains in the supply system.

Fig. 4 illustrates a schematic drawing of an embodiment of an installation 50 for supplying wash water. The water supply pipeline 51 is connected to the ultrapure water production unit 54 . The ultrapure water injection unit 55 is configured to supply ultrapure water from the ultrapure water production unit 54 through the supply line 52. The first end of the supply line 52 is connected to the ultrapure water injection unit 55, and the second end is connected to the semiconductor washing device. The ultrapure water injection unit 55 has access to an inert gas source, indicated by a gas pipeline 56, connected to a source located, for example, in the service area. Alternatively, a gas reservoir 57 may be provided.

In one embodiment, ultrapure water production unit 54 produces ultrapure water on demand, as will be described in more detail below. Ultrapure water is supplied to a plurality of containers 60. Preferably, containers 60 are filled sequentially, thus providing a phase shift release procedure, as will be described in more detail below. When the ultrapure water from the tank 60 is to be released into the supply line 52, a gas connection 59 is established between the gas line 56 containing the compressed inert gas and the first end of the tank 60 to be emptied. Thus, the compressed inert gas pushes the contents of the tank 60 through the second end into the supply line 52 for further transfer to the flushing device. An inert gas at a standard pressure of 30 pounds per square inch (psi) is usually already available in most clean zone facilities and can advantageously be used for such purposes as well. The ultrapure water injection unit 55 is configured to release one container 60 at a time during the water supply phase. This can also be provided with either a movable gas connection 59 as shown in the drawing, or fixed gas connections with individually controlled valves.

In other words, the ultrapure water production unit 54 includes a plurality of tanks 60 into which the produced ultrapure water is introduced and from which the produced ultrapure water is supplied to the supply line 52.

In other embodiments, only one container can be used to receive freshly produced ultrapure water to be fed into the supply pipeline.

Also, in other embodiments, pumping when supplying ultrapure water through the supply pipeline can be provided by other means, for example, by pumping.

The ultrapure water injection unit 55 is configured to purge the supply line 52 of water with an inert gas after supplying a predetermined amount of ultrapure water through said supply line 52. If additional volumes or pipes are used to contact the ultrapure water, such as, for example, the tanks 60 of FIG. . 4, they are also cleaned after use. For this purpose, an inert gas is used to blow out the remaining ultrapure water from the supply line 52 and at least partially dry the interior surfaces of the supply line 52. This ensures that there is no water remaining for a longer time in the supply line 52 (or container, if any) which, in turn, ensures that no contaminant particles or contaminant material is dissolved on the inner surface of the supply line 52.

The wash water supply unit 50 further comprises an operation control unit 53 controlling the operation of the ultrapure water production unit 54 . The operation control unit 53 is configured to receive a request for ultrapure water. The amount of ultrapure water to be produced is either predetermined or attached to the request. Thus, the operation control unit 53 is preferably configured to be able to set a predetermined amount of ultrapure water. The operation control unit 53 is configured to control the ultrapure water production unit in response to a request to produce a predetermined amount of ultrapure water.

Preferably, the ultrapure water request is also accompanied by a supply time at which the ultrapure water needs to be supplied. The operation control unit 53 preferably determines a production start time that is suitable for ensuring that the requested amount of freshly produced ultrapure water is provided at the requested time. This production time must be scheduled to ensure that ultrapure water is available when flushing is to begin, so that delays do not occur in the production line. However, at the same time, it is necessary to plan the production line to ensure that the average time between production and consumption remains as short as possible, i.e. that the last ultrapure water droplets produced are produced just before they are fed into the supply line 52.

In other words, the operation control unit 53 is configured to control the timing of the operation of the ultrapure water production unit 54 to provide a predetermined amount of freshly produced ultrapure water at a time set by the received command.

In the embodiment of FIG. The 4 tanks 60 can be filled sequentially, and when the semiconductor washer is ready to receive ultrapure water, the tanks 60 are released in the same order. This even allows the timing to be optimized so that the last (several) containers 60 can still be filled at the same time that the first containers are released. Thus, the storage time in containers is reduced.

Preferably, the predetermined amount of ultrapure water is equal to the amount of water required for the washing operation in the semiconductor washer as described above.

In a preferred embodiment, the installation for supplying wash water 50 includes a water analysis unit. Such a block is configured to measure the content of particles in a sample volume of ultrapure water extracted from a given amount of ultrapure water. The water from the ultrapure water sample volume cannot be re-fed to the wash procedure after analysis, which means that the specified amount of ultrapure water must also compensate for this withdrawn volume. In this way, verification of the purity of ultrapure water can be ensured. If the number of defective semiconductor products becomes too high, it is possible to refer to the quality data of the actual water used, which can help to detect defective parts of the production line. Such an analysis can be performed for at least particle sizes greater than and not much less than 100 nm, according to standard analysis tools which are per se known in the art, for example based on accurate resistivity measurements.

The embodiments described above are to be understood as a few illustrative examples of the present invention. Those skilled in the art will appreciate that various modifications, combinations, and changes may be made to the embodiments without departing from the scope of the present invention. In particular, decisions regarding different parts in different embodiments can be combined in other configurations, as far as technically possible. However, the scope of the present invention is defined by the appended claims.

Claims (32)

1. Installation (50) for supplying wash water, containing unit (54) for the production of ultrapure water; And a supply pipeline (52), the first end of which is connected to the outlet of said ultrapure water production unit (54); wherein the second end of said supply pipeline is configured to be connected to the device (40) for washing semiconductors, characterized in that an operation control unit (53) for said ultrapure water production unit (54); wherein said operation control unit (53) is configured to control said ultrapure water production unit (54) to produce a predetermined amount of ultrapure water upon request; And an ultrapure water injection unit (55) having access to an inert gas source; moreover, the injection unit (55) for ultrapure water is configured to clean said supply pipeline (52) from water with said inert gas after supplying said predetermined amount of ultrapure water through said supply pipeline (52). 2. Installation (50) for supplying wash water according to claim 1, characterized in that said injection unit (55) for ultrapure water is configured to conduct said predetermined volume of ultrapure water through said supply pipeline (52), pumped by said inert gas. 3. Installation (50) for supplying wash water according to claim 1 or 2, characterized in that said ultrapure water production unit (54) is configured to operate in a clean zone (20). 4. Installation (50) for supplying wash water according to any one of paragraphs. 1-3, characterized in that said operation control unit (53) is configured to allow setting said predetermined amount of ultrapure water. 5. Installation (50) for supplying wash water according to any one of paragraphs. 1-4, characterized in that said operation control unit (53) is configured to control the timing of operation of said ultrapure water production unit (54) to supply said predetermined amount of freshly produced ultrapure water at the time specified by the received request. 6. Installation (50) for supplying wash water according to any one of paragraphs. 1-5, characterized in that said ultrapure water production unit (54) comprises a plurality of containers (60) into which produced ultrapure water is introduced, and from which said produced ultrapure water is supplied to said supply pipeline (52). 7. Installation (50) for supplying wash water according to any one of paragraphs. 1-6, characterized by a water analysis unit configured to measure the content of particles in a sample volume of ultrapure water extracted from said predetermined amount of ultrapure water. 8. Semiconductor washing system (30), characterized installation (50) for supplying wash water according to any one of paragraphs. 1-7; And a device (40) for washing semiconductors, to which said second end of said supply pipeline is connected. 9. Semiconductor washing system (30) according to claim 8, characterized in that said predetermined amount of ultrapure water is equal to the amount of water required for the washing operation in said semiconductor washing device (40). 10. Semiconductor manufacturing system (1), comprising a clean zone (20) containing at least one semiconductor production area (10); And service area (25) located in connection with said clean area (20), characterized in that at least one of said at least one semiconductor production area (10) comprises a semiconductor washing system (30) according to claim 8 or 9 located inside said clean zone (20); moreover, water from said service area (25) is supplied to said installation (50) for supplying ultrapure water of said semiconductor washing system (30). 11. A method for supplying wash water, comprising steps in which produce (S4) a predetermined amount of ultrapure water upon request; And supply (S6), in connection with said production, said predetermined amount of ultrapure water to the device (40) for washing semiconductors through the supply pipeline (52), characterized by an additional step in which purifying (S8) said supply line (52) from water by means of an inert gas after said supply of said predetermined amount of ultrapure water through said supply line (52). 12. The method according to claim 11, characterized in that said supply of said ultrapure water through said supply conduit (52) comprises the step of injecting said ultrapure water through said supply conduit (52) by means of said inert gas. 13. The method according to claim 11 or 12, characterized by the additional step of measuring the content of particles in a sample volume of ultrapure water extracted from said predetermined amount of ultrapure water.

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