In the fields of Internet of Things, smart homes, and industrial control,Temperature and humidity chips (such as SHT3x, HTU21D, etc.) are the core components for environmental perception.However, many users have found that the surface of the chip is covered with a layer of white glue. Can this "white glue" be removed? Will removing it affect chip performance? This article will analyze from three aspects: technical principles, risk assessment, and solutions.

　　1、 Unveiling the 'identity' of white glue: protection or restraint?

The white glue on the surface of the chip is usually epoxy resin or silicone, and its functions include:

1. Mechanical protection: prevent chips from being damaged due to vibration or collision during transportation and welding processes;

2. Environmental isolation: block water vapor, dust, and chemicals to prevent sensitive components (such as moisture sensitive films) from being contaminated;

3. Stress buffering: Reduce stress damage to chips caused by thermal expansion and contraction of PCB boards.

　　2、 Can the white glue be removed? The key lies in the application scenario

1. Irremovable situations

High humidity environment: If the chip is used for outdoor, agricultural, or medical equipment (humidity>85% RH), white glue is the "lifeline" to prevent the failure of the moisture sensitive film.

Precision measurement requirements: Removing white glue may result in temperature measurement deviation of ± 0.5 ℃ or more, and humidity deviation of ± 5% RH or more.

Unprotected design: If the chip does not integrate a protective coating (such as Parylene), additional packaging is required after removing the white glue, which increases the cost by 30% -50%.

2. Removable situations

Laboratory testing: When verifying the performance of the chip in the short term, it is recommended to soak the softened white glue in isopropanol and carefully peel it off, but the protection should be restored within 48 hours.

Customized packaging: If the chip needs to be integrated into a metal casing or airtight cavity, the white glue can be removed and repackaged through a dispensing process.

Repair and replacement: When the chip pins are damaged and need to be repaired, the white glue can be partially removed, but the operating temperature should be controlled below 80 ℃ to avoid damaging the wet film.

　　3、 Alternative solution: The problem can be solved without removing the white glue

If poor heat dissipation or space occupation is caused by white glue, the following measures can be taken:

1. Slot design: Reserve heat dissipation slots for chips on the PCB to reduce temperature through air convection;

2. Thermal conductive adhesive replacement: Apply low viscosity thermal conductive silicone on the bottom of the chip to improve thermal conductivity efficiency;

3. Secondary packaging: Cover the chip with transparent epoxy resin, which retains the function of white glue and enhances mechanical strength.

　　Conclusion: White glue is "armor" rather than "shackles"

The white glue essence of temperature and humidity chips is a low-cost and highly reliable protection solution. Unless there are clear customized requirements or short-term testing scenarios, it is not recommended to remove them. For ordinary applications, instead of risking peeling off the white glue, it is better to improve system stability by optimizing PCB layout, adding protective coatings, and other methods. In the field of environmental perception, "protection first" is always the golden rule of chip design.