WO2019080642A1

WO2019080642A1 - Dry ice cleaning method

Info

Publication number: WO2019080642A1
Application number: PCT/CN2018/103393
Authority: WO
Inventors: 张青竹
Original assignee: 张青竹
Priority date: 2017-10-20
Filing date: 2018-08-31
Publication date: 2019-05-02
Also published as: CN107876513A

Abstract

A dry ice cleaning method comprising the following steps: heating a mold to be cleaned; acquiring a corresponding amount of dry ice from a dry ice storage on the basis of the dirtiness of the surface of the mold to be cleaned; hand-holding a cold spray gun, pressing a button on the cold spray gun, aiming a nozzle at the dirty surface of the mold to be cleaned, and spraying dry ice particles, thus rapidly cooling the dirt on the surface to embrittlement and bursting. The dry ice cleaning method utilizes dry ice for a low-temperature impact condition to blow and peel away a dirt layer, thus removing dirt.

Description

Dry ice cleaning method

Technical field

The invention relates to the field of mold cleaning technology, in particular to a dry ice cleaning method.

Background technique

In the prior art, a semiconductor package mold, an integrated circuit IC, an LED, and a package system are generally cleaned by using a mold strip, a clear mold strip, a mold strip, or a mold wash water. When cleaning with a washing strip, a clearing strip or a washing water, it is necessary to heat the mold first, press the washing strip into the groove of the mold, and use the washing strip to stick the dirt on the surface of the mold for cleaning. In the corners of the mold that are difficult to clean, in addition to washing the mold strip, clearing the mold strip, moistening the mold strip or washing the mold water, the mold is cleaned with an alkaline chemical. When the mold is cleaned by the above method, the mold needs to be disassembled. Disassembly and assembly of a set of molds is not only time-consuming and labor-intensive, but also the mold is easy to cause damage during the disassembly process. The cost of a set of molds is tens to millions, and the damage cost is huge. The traditional cleaning method adopts the washing strip, the clearing strip and the running strip, which need hot melt and cooling, which is very time consuming, and the time taken for hot melting and cooling of the washing strip and the clearing strip takes up the entire cleaning process time. Nearly 50%, production efficiency is extremely low. In addition, the washing water and alkaline chemicals are also likely to cause damage to the metal surface, requiring re-plating and increasing maintenance costs. In addition, toxic substances in alkaline chemicals are prone to safety hazards to workers, endangering workers' health, and emissions of alkaline chemicals can also cause environmental pollution problems. Therefore, there is a need for a safe, efficient, environmentally friendly, and economical cleaning method for cleaning semiconductor package molds.

technical problem

In view of the deficiencies of the prior art, the present invention provides a dry ice cleaning method capable of safely, efficiently, environmentally and economically cleaning a semiconductor package mold, saving washing time and improving production efficiency.

Technical solution

The technical solution of the present invention is: Providing a dry ice cleaning method, comprising the following steps:

Step 1: heating the mold to be cleaned;

Step 2: Obtain a corresponding amount of dry ice from the stored dry ice according to the degree of dirt on the surface of the mold to be cleaned;

Step 3: Hold the cold spray gun, press the cold spray gun button, point the nozzle on the dirt surface of the mold to be cleaned, spray dry ice particles, and make the surface dirt freeze to embrittlement and burst.

Preferably, the mold to be cleaned is any one of a semiconductor package mold, a photoelectric mold, and a microelectronic mold.

Preferably, the barrel of the cold spray gun can be correspondingly lengthened according to the actual cleaning needs of the mold to be cleaned.

Preferably, the end of the barrel of the cold spray gun near the nozzle can be bent at different angles to accommodate the cleaning of different dirt locations of the mold to be cleaned.

Preferably, the gun handle of the cold spray gun is provided with an impact-proof buffer structure, and the buffer structure is made of any one or a combination of cotton cloth, rubber cushion or elastic plastic.

Beneficial effect

1. It replaces the traditional cleaning method of cleaning the semiconductor mold by using the washing strip, the clearing strip, the moulding strip or the washing water and the alkaline chemical. In the conventional method, the hot-melted washing strip and the clear strip will be produced. The toxic gas is not environmentally friendly, and the invention avoids the environmental pollution problem caused by the use of the washing strip, the clear mold strip or the mold strip or the washing water and the alkaline chemical cleaning.

2, dry ice cleaning is the use of physical principles to clean the mold, cleaning speed, no damage to the mold, thus avoiding the use of traditional washing strips, clear mold strips or mold strips or washing water and alkaline chemicals The cleaning method brings waste of multiple electroplating, reduces costs, does not generate harmful gases, does not cause secondary pollution, and is safe and environmentally friendly.

3. During the cleaning process, it is not necessary to disassemble and clean the mold, which saves the time of disassembly and assembly of the mold and the time when the mold strip, the clear mold strip and the mold strip need to be hot melted and then cooled by the traditional method. The original 2 to 3 hours saved to 20 minutes, fast and efficient, greatly improving the cleaning efficiency, while the mold also avoids damage caused by disassembly.

4. The cold spray gun can be used for fixed-point cleaning of specific parts of the mold, which does not need to be cleaned every time, which is very economical and convenient.

5. The method is suitable for the cleaning of semiconductor packaging molds, photoelectric molds and micro-electronic molds. It has a good cleaning effect on LED molds and integrated circuit IC molds, and has a broad market prospect.

BEST MODE FOR CARRYING OUT THE INVENTION

A dry ice cleaning method comprising the following steps:

Step 1: heating the mold to be cleaned;

The mold to be cleaned is any one of a semiconductor package mold, a photoelectric mold, and a microelectronic mold. The barrel of the cold spray gun can be lengthened according to the actual cleaning needs of the mold to be cleaned. The length of the straight pipe section of the barrel is 25cm-40cm, and the end of the barrel of the cold spray gun near the nozzle can be bent into different angles. The nozzle material is one of stainless steel or aluminum alloy or nylon composite material or alloy material, and the inner diameter of the nozzle is 0.6cm or 0.8cm, in order to meet the cleaning of the different dirt of the mold to be cleaned (the material is stuck in the production process).

The front end of the cold spray gun body can be directly screwed to nozzles of different specifications and materials to suit the cleaning of different specifications of the mold, and the nozzles of different model specifications include a circular nozzle or a nozzle tube with different bending angles of the nozzle tube body. The rectangular nozzles with different bending angles are made of nylon composite material or aluminum alloy or stainless steel or alloy material. When cleaning the dirt on the concave surface of the mold surface, a circular nozzle is generally used. The cold spray gun realizes point-to-point cleaning and the cleaning position is accurate. When cleaning the surface of the mold with large dirt area, a cold spray gun with a rectangular nozzle is generally selected, and the dry ice particles sprayed from the rectangular nozzle are sprayed into the dirt in a rectangular strip. The surface, the contact area with the mold surface is increased, the cleaning force is increased, and the cleaning time is saved. The cold spray gun can be operated by hand, or can be cleaned by installing the moving bracket on the dirty surface of the cleaning mold driven by the moving bracket.

Cold spray gun working principle: The dry ice particles are accelerated to supersonic speed by compressed air and sprayed onto the surface of the mold to be cleaned. When the dry ice is cleaned, the spray medium (dry ice particles) is accelerated by the high-pressure airflow, and is sprayed through the nozzle to impact the surface of the mold to be cleaned, effectively removing the target dirt. This is because the dry ice pellets have extremely low temperatures and are used for decontamination cleaning to create a temperature difference between the cleaning surface contamination layer and the adhered substrate layer. Since different materials have different coefficients of thermal expansion, the surface contamination layer and the adhered substrate layer The temperature difference between them will destroy the physical bond between the two materials, and the adhesion layer will be cracked and embrittled by the difference in shrinkage. At the same time, at the moment of impact, the dry ice ruptures and enters the crack at the same time, and the volume expands nearly twice in a few thousandths of a second, causing a “micro explosion”, which sweeps off the dirt layer and removes dirt. Under the low temperature impact condition of dry ice, the pollution layer on the surface of the cleaning material is cracked. Due to the strong temperature difference, the crack of the pollution layer is intensified, the debris of the pollution layer begins to peel off, the dry ice sublimes in a few thousandths of a second, and the volume expands nearly 600-800. Double, causing a "micro explosion", sweeping off the dirt layer and removing dirt. Since the dry ice particles are sprayed onto the surface of the mold to be cleaned by acceleration, the impact force generated during the injection will cause a reverse pressure on the cold spray gun, and the person may hold the gun when the handle is unstable. If the hand is accidentally released, the cold spray gun When it is hit on the mold, it will damage the high mold, and it will also endanger the personal safety. The cold spray gun of the present invention has a buffer structure on the handle, and the cushion structure is made of cotton. Any one or combination of cloth, rubber cushion or elastic plastic.

Industrial applicability

The above are only the preferred embodiments of the present invention, and all changes and modifications made within the scope of the claims of the present invention should be construed as the scope of the claims.

Claims

A method for cleaning dry ice, comprising the steps of:

Step 1: heating the mold to be cleaned;

Step 2: Obtain a corresponding amount of dry ice from the stored dry ice according to the degree of dirt on the surface of the mold to be cleaned;

Step 3: Hold the cold spray gun, press the cold spray gun button, point the nozzle on the dirt surface of the mold to be cleaned, spray dry ice particles, and make the surface dirt freeze to embrittlement and burst.
The dry ice cleaning method according to claim 1, wherein the mold to be cleaned is any one of a semiconductor package mold, a photoelectric mold, and a microelectronic mold.
The dry ice cleaning method according to claim 1, wherein the barrel of the cold spray gun can be subjected to a corresponding lengthening process according to the actual cleaning needs of the mold to be cleaned.
The dry ice cleaning method according to claim 1, wherein one end of the barrel of the cold spray gun near the nozzle is bendable at different angles to accommodate cleaning of different dirt positions of the mold to be cleaned.
The dry ice cleaning method according to claim 1, wherein the gun handle of the cold spray gun is provided with an impact-proof buffer structure, and the buffer structure is made of cotton cloth, rubber cushion or elastic plastic. Any one or combination of several.