阅读说明：本技术 一种基于树脂垫片的基板封装包封模具清洗方法 (Substrate packaging and encapsulating mold cleaning method based on resin gasket ) 是由 杨国宏 于 2020-06-17 设计创作，主要内容包括：本发明提供了一种基于树脂垫片的基板封装包封模具的清洗方法。本发明所述方法能够显著的简化芯片封装包封清洗模具工艺流程,提高模具清洗质量,减低封装成本和缩短加工周期。(The invention provides a cleaning method of a substrate packaging and encapsulating mold based on a resin gasket. The method can obviously simplify the technological process of encapsulating, encapsulating and cleaning the die for chip encapsulation, improve the cleaning quality of the die, reduce the encapsulation cost and shorten the processing period.)

1. A substrate packaging mold cleaning method based on a resin gasket is characterized by comprising the following steps:

(1) and (3) conventional cleaning: opening a mold washing procedure, putting melamine particles into a mold sleeve, putting a resin gasket on the surface of a mold, starting an injection molding program, closing the mold to complete the program, and taking down the resin gasket after injection molding after mold opening;

(2) wax pattern washing: and (4) putting the wax mold material and the resin gasket, opening the injection molding process, closing the mold, completing the program, and taking down the resin gasket after opening the mold.

2. The method of claim 1, wherein the wax molding compound of step (2) is HITACHI RP-2.

3. The method of claim 1, wherein the regular cleaning in step (1) is performed in 4 or more modules.

4. The method according to claim 1, wherein the wax pattern washing in step (2) is performed 2 or more times.

5. The method of claim 1, wherein the step (1) comprises, after the mold washing process is started, putting melamine in the mold, putting the resin pad on the working surface of the mold, starting the injection molding process, closing the mold, completing the process, removing the resin pad after the mold is opened, and repeating the process 4 times; and (2) putting wax mold materials and the resin gasket, opening an injection molding process, closing the mold, completing the program, taking down the resin gasket after opening the mold, and repeating the process for 2 times until the resin gasket is cleaned.

6. The method according to any one of claims 1 to 5, wherein the resin gasket obtained in steps (1) and (2) has a high temperature resistance of 200 ℃ and a 30 ton injection molding pressure resistance.

7. The method according to any one of claims 1 to 5, wherein the resin gasket is prepared by:

(1) drawing a corresponding resin gasket drawing based on a substrate drawing;

(2) and (3) processing and molding the resin gasket on the plane resin sheet in a carving mode according to the drawing of the resin gasket in the step (1).

8. The method of claim 7, wherein the resin has a resistance to a high temperature of 200 ℃ and a resistance to an injection pressure of 30 tons.

9. The method of claim 1, wherein the substrate is a window BGA or BGA substrate.

Technical Field

The invention belongs to the technical field of microelectronic industry, particularly relates to the technical field of substrate packaging in the microelectronic industry, and particularly relates to a substrate packaging and packaging mold cleaning method based on a resin gasket.

Background

The basic manufacturing flow of chips generally consists of die Bonding, Wire Bonding, Encapsulation and Testing. The packaging is to wrap the integrated circuit by using packaging materials to play a role in protection and isolation. In a chip packaging process chain, a packaging process is a process for plastically packaging, fixing and protecting an exposed chip and a lead, and plays a very critical role in the whole packaging process.

The mold is a place for molding and curing the plastic packaging material. Due to the action of heat, small molecular substances in the plastic packaging material can volatilize and be enriched on the die. Long-term heating can denature, cure or even carbonize these small molecules. Pollutants attached to the surface of the mold can obviously affect the flowability of the plastic packaging material in the mold cavity of the mold, so that the plastic packaging effect is affected. If carbon deposition is generated, the insoluble solid particles may flow into the chip along with EMC, and may impact gold wires, the chip and the like, thereby causing quality hidden trouble. Since mold contamination affects products and processes, such as pitted surface, poor plastic encapsulation, gold wire displacement, chip cracking, and other quality problems are common, the mold needs to be cleaned periodically.

CN109433741A discloses a method for cleaning a chip packaging mold by using dry ice, which aims to solve the problem that packaging plastics remain on the chip packaging mold and reduce the quality of a chip packaged product.

CN1225349C discloses a method for removing stains on the surface of a mold in molding a curable resin molding material, which comprises using a melamine-containing resin as a mold cleaning resin.

The traditional mould cleaning mode comprises five steps: the cleaning process is shown in fig. 1, and comprises the steps of normal cleaning (normal cleaning) → tank cleaning (pot cleaning) → cake cleaning (sheet cleaning) → wax mold cleaning (wax cleaning). The method has long cleaning time, consumes more cleaning materials (melamine), has unstable cleaning quality and is easy to cause mold blockage.

In addition, the methods disclosed in the prior art only clean the plane of the mold first and then clean the injection molding sleeve, which is cumbersome to operate.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the invention provides a cleaning method of a substrate packaging and encapsulating mold based on a resin gasket, which aims to solve the technical problems that the traditional mold cleaning method is long in time consumption, consumes a large amount of cleaning materials, and is unstable in mold cleaning quality.

The technical scheme adopted by the invention for solving the technical problems is as follows: the invention provides a cleaning method of a substrate packaging and encapsulating mold based on a resin gasket, which comprises the following steps:

(1) and (3) conventional cleaning: opening a mold washing procedure, putting melamine particles into a mold sleeve, putting a resin gasket on the surface of a mold, starting an injection molding program, closing the mold to complete the program, and taking down the resin gasket after injection molding after mold opening;

(2) wax pattern washing: and (4) putting the wax mold material and the resin gasket, opening the injection molding process, closing the mold, completing the program, and taking down the resin gasket after opening the mold.

Further preferably, the wax molding compound in the step (2) is HITACHI RP-2.

Further preferably, the conventional cleaning in the step (1) is performed for more than 4 modules;

and (3) washing the wax pattern for more than 2 times.

Further preferably, the method comprises: after a mold washing procedure is started, melamine is put in, then a resin gasket is put on a working surface of a mold, an injection molding program is started, the mold is closed, the program is completed, the resin gasket after injection molding is taken down after the mold is opened, and the process is repeated for 4 times; and (2) putting wax mold materials and the resin gasket, opening an injection molding process, closing the mold, completing the program, taking down the resin gasket after opening the mold, and repeating the process for 2 times until the resin gasket is cleaned.

Further, in the above method, it is preferable that the resin gasket in steps (1) and (2) has a resistance to a high temperature of 200 ℃ and a resistance to an injection molding pressure of 30 tons.

Further, in the above method, the resin gasket is prepared by the following method:

(1) drawing a resin gasket drawing based on a substrate drawing;

(2) and (4) processing and molding the planar resin sheet by using an engraving mode according to the drawn drawing of the resin gasket.

Further, preferably, the resin has the characteristics of high temperature resistance of 200 ℃ and 30-ton injection pressure resistance.

Drawing a resin gasket drawing based on a substrate drawing in the step (1), wherein the drawing of the resin gasket drawing with consistent size is drawn according to the substrate drawing; the drawn resin gasket drawing is basically consistent with the substrate drawing, and the resin gasket machined and molded through the drawing is basically consistent with the substrate in appearance.

The substrate mold of the present invention has the meaning conventional in the art, including, for example, a window BGA or BGA substrate. The substrate die cleaning method based on the resin gasket has universality. The resin shim according to the present invention is designed according to the substrate to be used for mold cleaning with substantially no difference.

The invention has the beneficial effects that:

firstly, compared with the traditional scheme that the surface of a mold is firstly coated with dust-free paper and matched with melamine to clean the surface of the mold, and then the injection molding rod is cleaned by the dust-free paper and matched with the melamine, the scheme of the invention can simultaneously clean the surface and the cavity by putting the melamine into the mold and putting the resin gasket on the working surface of the mold and using a direct injection molding mode, thereby omitting two steps of tank cleaning (pot cleaning) and cake cleaning (sheet cleaning) in the prior art, remarkably reducing the usage amount of granular melamine and flaky melamine, greatly shortening the cleaning time, and saving the cleaning time by more than 30 percent.

Secondly, after the technical scheme of the invention is added with the mold cleaning resin gasket, the mold cleaning material is smoothly demoulded, and the beneficial effects that the melamine resin is not adhered and the mold is not blocked are achieved.

Thirdly, the resin gasket used in the scheme of the invention has the characteristics of high temperature resistance (200 ℃) and high pressure resistance (30 tons of injection molding pressure), does not deform, does not generate adhesive substances under high temperature and high pressure, does not generate additional pollution, and also has the function of helping the cleaning material to demould.

Fourthly, the method for cleaning the substrate packaging mold based on the resin gasket solves the problems of high cost and unsuitability for industrial application caused by substrate mold cleaning.

Drawings

The technical solution of the present application is further explained below with reference to the drawings and the embodiments.

Fig. 1 is a flow chart of a conventional cleaning process for a substrate packaging encapsulation mold;

FIG. 2 is a flow chart of a cleaning process for a substrate packaging and encapsulating mold according to the present invention;

FIG. 3 is a drawing design drawing and a picture of a real object of a mold cleaning resin gasket designed by the method of embodiment 1 of the invention; wherein, the resin pad row 5X24, the size 240x74x0.25(5 grooves 8 rows), the unit mm, wherein the thickness is 0.25 plus or minus 0.038 mm; FIG. 3A is a photograph showing a product of a resin gasket, and FIG. 3B is a design drawing of the resin gasket corresponding to FIG. 3A;

FIG. 4 is a drawing design drawing and a picture of a real object of a mold cleaning resin gasket designed by the method of embodiment 2 of the invention; wherein, the resin pad row 6X27, size 240x74x0.25(6 groove 9 rows), unit mm, wherein the thickness is 0.25 + -0.038 mm; FIG. 4A is a photograph of a product, and FIG. 4B is a design drawing corresponding to FIG. 4A;

FIG. 5 is a drawing design drawing and a picture of a real object of a mold cleaning resin gasket designed by the method of embodiment 3 of the invention; wherein, the resin pad has an array of 6 holes, the size of 240x74x0.21 and the unit mm, and the thickness of 0.21 +/-0.025 mm; FIG. 5A is a photograph of a product, and FIG. 5B is a design drawing corresponding to FIG. 5A;

FIG. 6 is a drawing design drawing and a picture taken of a mold cleaning resin gasket designed by the method of embodiment 4 of the invention; wherein the resin pad array is 6X30, the size is 240x77.5x0.25, the unit mm is, and the thickness is 0.25 +/-0.038 mm; FIG. 6A is a photograph of a product, and FIG. 6B is a design drawing corresponding to FIG. 6A;

fig. 7 is a diagram illustrating an effect of the substrate mold after cleaning according to the embodiment of the present invention.

FIG. 8 is a layout view of a Window BGA substrate in accordance with embodiment 1 of the present invention;

fig. 9 is a design diagram of a Window BGA substrate according to embodiment 2 of the present invention;

fig. 10 is a layout view of a BGA substrate according to embodiment 3 of the present invention;

FIG. 11 is a layout view of a Window BGA substrate in accordance with embodiment 4 of the present invention;

table 1: resin shim product array and dimensions corresponding to FIGS. 3-6

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.