How does ULPA control material release in thin film deposition and display manufacturing?

Thin film deposition and control in display manufacturingThe core of ULPA filter material release is to disassemble the filter into three components: filter material, sealant, and hot melt adhesive for separate control. You cannot just look at the type of filter material. The organic release of PTFE filter material is indeed very low, but sealants and hot melt adhesives are the main sources of ionic and organic pollution. High temperature or high humidity conditions will further increase the release. The interior of thin film deposition equipment and the display panel manufacturing cavity are sensitive to molecular contamination. As a terminal filter, ULPA itself may become a source of secondary pollution for AMC. The outgassing check during selection cannot stop at the filter material level. Aili Industrial’s product line coverageHEPA/ULPA filters andEFU equipment side fan filter unit，PTFE HEPA/ULPA filters can evaluate filter materials according to low outgassing requirements, and the outgassing data of sealing materials and hot melt adhesives can be confirmed with product data.

1. First, look at where the release comes from: each of the three components handles a type of pollution.

The ULPA filter in the EFU of semiconductor equipment consists of three parts: filter material, sealant and hot melt adhesive, all three of which are potential sources of AMC.-4-10

The highest total ion release was from the sealant (22.43 ppbw) and the lowest from the filter material (9.10 ppbw). Catalysts and additives remaining during the curing process of sealants are major contributors to ionic contamination.

In terms of organic release, the organic release of PTFE filter material is close to undetectable under both standard and severe conditions, but the organic release of sealants and hot melt adhesives can reach 621 ppbw. Sealants release mainly C₄-C₈ high boiling point esters, while hot melt adhesives release C₈-C₁₆ polyolefin wax fragments.-15

Among metal releases, boron and sodium are the two most sensitive contaminants to semiconductor yield. The sealant has the highest total metal release (20.29 ppbw), of which sodium contributes significantly. The boron release of the filter material increases from 0.84 ppbw to 2.41 ppbw under high temperature conditions, indicating that temperature will accelerate diffusion. The relationship between levels and filtering requirements can be found inISO cleanliness level comparison。-15

2. Humidity is an acceleration factor, and film deposition and display manufacturing must be controlled separately.

Under high-humidity conditions (90% RH), the ion release amount of the filter material will increase by 4.88 times, confirming that moisture adsorption is the main acceleration factor for ion release. If there are humidity fluctuations inside the thin film deposition equipment (such as opening and closing of the chamber, recovery after maintenance), the ion release of ULPA may increase for a short time. If ULPA is exposed to high humidity near wet processes in manufacturing, this impact also needs to be evaluated.-4-10

Aili Industry isWhen matching PTFE HEPA/ULPA filters , the material suitability can be evaluated based on the working humidity conditions.the liquid tank seal ULPA filter are confirmed according to the environmental conditions.The sealing liquid and tank material of For non-standard ULPA filter projects, the material plan can be checked according to the internal temperature and humidity range of the equipment. For matching of materials and working conditions, please refer toHEPA FAQs and Selection Guide。

3. Checking method during model selection: Require data based on components, do not draw conclusions based on filter materials

At the filter material level, PTFE has clear advantages in organic release and is suitable for thin film deposition and display manufacturing scenarios that are sensitive to organic condensates (AMC-MC). However, PTFE does not solve the problems of sealants and hot melt adhesives, so you cannot assume that the overall release is controllable just because you choose PTFE filter material.

For sealants and hot-melt adhesives, suppliers are required to provide ionic, organic, and metal release data for sealants and hot-melt adhesives, rather than only data for filter media. Low release sealants reduce organic and ionic contributions. If high-temperature processes are involved in display manufacturing, release data under high-temperature conditions must be obtained. Normal-temperature data cannot represent high-temperature performance.

Aili Industry isThe HEPA/ULPA filter package can provide gas release data of filter materials and sealing materials according to project requirements.The filter material data of PTFE HEPA/ULPA filters are provided separately, and the outgassing data of sealants and hot melt adhesives are confirmed by model. The selection of sealing materials in the equipment-side EFU package can be checked according to the internal environmental conditions of the equipment. For the correlation between gas release data and selection verification, please refer toULPA ultra-high efficiency filter FAQ and selection guide。

4. Special considerations in display manufacturing: OLED processes are more sensitive to organic pollution

Thin film deposition in display panel manufacturing is similar to the semiconductor front-end process, but the substrate size is larger and the cavity environment control method is different. In the evaporation and encapsulation processes that are sensitive to organic contamination in OLED manufacturing, the release of ULPA sealant and hot melt adhesive needs to be evaluated separately. The selection logic is consistent with the EFU on the semiconductor equipment side: check the release data by component, and take the value based on actual temperature and humidity conditions. You cannot judge the whole based on the promotion of low-release filter materials.

Aili Industry isEFU equipment end fan filter unit package, the air supply plan can be confirmed according to the internal space and process conditions of the displayed equipment.In the Ultra-thin EFU configures local air supply in the compact space of panel equipment.The FFU computer group control system records the operating status for verification and comparison. Please refer to the cooperation between equipment end air supply and material control.EFU FAQ and technical support。

5. Related questions and answers

If you choose PTFE filter material, you don’t have to worry about the sealant outgassing?
cannot. PTFE only solves the organic release at the filter material level. The ion and organic release of sealants and hot melt adhesives still need to be confirmed separately, and the three must be checked separately.

Can the gas release data at normal temperature represent high-temperature working conditions?
cannot. High temperature will accelerate diffusion. The boron release of the filter material increases from 0.84 ppbw to 2.41 ppbw under high temperature. The organic release of the sealant increases by about 40% under harsh conditions. For high-temperature processes, data on corresponding conditions should be obtained.

Is the logic of choosing ULPA for display manufacturing the same as that of semiconductor front-end?
The basic logic is the same: check the release according to the component and take the value according to the actual temperature and humidity. The OLED process in display manufacturing is sensitive to organic contamination, and data on sealants and hot melt adhesives especially need to be confirmed.

6. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

PTFE HEPA/ULPA high efficiency filter

Ultra-thin EFU

HEPA FAQs and Selection Guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industrial’s product line coverageHEPA/ULPA filters andEFU equipment side fan filter unit，PTFE HEPA/ULPA filters can evaluate filter materials according to low outgassing requirements, and the outgassing data of sealing materials and hot melt adhesives can be confirmed with product data.PTFE HEPA/ULPA filter matching materials are evaluated according to the working conditions and humidity conditions.the liquid tank seal ULPA filter are confirmed according to the environmental conditions.The sealing liquid and tank material of Non-standard ULPA filter projects check the material plan according to the internal temperature and humidity range of the equipment.HEPA/ULPA filter packages can provide outgassing data of filter materials and sealing materials according to project requirements;the fan filter unit at the EFU equipment end .Confirm the air supply plan according to the internal space and process conditions of the display equipment when matching Ultra-thin EFU configures local air supply in the compact space of panel equipment.The FFU computer group control system records the operating status for verification and comparison. Provide process objectives, equipment structure and temperature and humidity conditions to further communicate ULPA material outgassing data and configuration suggestions. The specific parameters and test range are based on the confirmed model and technical documents.