A method for testing the bond strength of glass fiber cloth and resin

Abstract

This invention discloses a method for testing the bonding strength between fiberglass cloth and resin, belonging to the field of PCB material inspection technology. The method includes: pre-treating a substrate to obtain an inner copper-free substrate; stacking a release film of a predetermined width on each of the upper and lower edges of the inner copper-free substrate, and then sequentially stacking a layer of PP and a layer of copper foil on the upper and lower surfaces; pressing the stacked parts together to obtain a sample; retrieving a sample strip of a predetermined size from the pressed sample; testing the tensile strength of the sample strip using a tensile tester, with the test result representing the bonding strength between the fiberglass cloth and resin. This method intercepts delamination, board bursting, and other problems at the incoming material inspection stage, preventing these issues from flowing into the PCB board and causing PCB board scrapping. It also allows for rapid identification of high-risk incoming batches, demonstrating high timeliness.

Description

Technical Field

[0001] This invention relates to a method for testing the bonding strength between fiberglass cloth and resin, belonging to the field of PCB material testing technology. Background Technology

[0002] With the continuous upgrading of electronic products, the number of layers, thickness, and electrical performance of PCBs are constantly increasing. To meet product requirements and improve electrical performance, the roughness of the copper foil on the PCB substrate is constantly decreasing, while resin and fiberglass cloth are continuously being upgraded and optimized. However, as the roughness of the copper foil decreases, the bonding strength also decreases. Therefore, coatings are added to the bonding surface of the copper foil to increase the bonding strength. This optimization process also brings about the problem of poor substrate bonding (mainly referring to the bonding strength between the resin and the copper-free substrate). Currently, the existing testing methods in the PCB industry can only test the bonding strength between the copper foil and the resin, but cannot test the bonding strength between the resin and the fiberglass cloth. Summary of the Invention

[0003] The purpose of this invention is to provide a test method for the bonding strength between fiberglass cloth and resin, which solves the problem that the bonding strength between resin and fiberglass cloth cannot be tested in the prior art, and intercepts problems such as delamination and board bursting at the incoming inspection end.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention provides a method for testing the bonding strength between fiberglass cloth and resin, comprising:

[0006] The substrate is pretreated to obtain a copper-free inner layer substrate;

[0007] A release film of a predetermined width is laminated on each of the upper and lower edges of the inner copper-free substrate, and then a layer of PP and a layer of copper foil are laminated on the upper and lower edges respectively.

[0008] After the layers are stacked, they are pressed together to obtain a template.

[0009] A template of the preset size is retrieved from the template obtained by pressing.

[0010] The tensile strength of the sample was tested using a tensile tester, and the test result was the bonding strength between the fiberglass cloth and the resin.

[0011] Furthermore, the substrate is selected from copper foil of HVLP grade or higher.

[0012] Furthermore, the pretreatment involves etching the substrate in the inner layer to create a copper-free inner layer substrate.

[0013] Furthermore, the preset width is 10~20mm.

[0014] Furthermore, the model number of the PP is 2116.

[0015] Furthermore, the copper foil has a thickness of 1 / 2 oz.

[0016] Furthermore, the spline is retrieved from the center of the template.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0018] This invention provides a method for testing the bonding strength between fiberglass cloth and resin. By pressing PP and an inner copper-free substrate together in the required position using PCB lamination, the bonding strength between the resin and fiberglass cloth is then tested. This method intercepts problems such as delamination and board bursting at the incoming inspection stage, preventing these problems from flowing into the PCB board and causing it to be scrapped. It can also quickly identify high-risk batches of incoming materials, and has high timeliness. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for testing the bonding strength between fiberglass cloth and resin according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the overlapping position of the release film provided in an embodiment of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0022] like Figure 1 As shown, a flowchart of a method for testing the bonding strength between fiberglass cloth and resin provided in an embodiment of the present invention includes:

[0023] S1. Pre-treat the substrate to obtain a copper-free inner layer substrate.

[0024] First, select the raw materials according to the copper foil type specified in the material specifications. Select a substrate with HVLP or higher grade copper foil, cut the substrate into 8cm×10cm size, and etch a copper-free plate into the inner layer of the substrate to obtain a copper-free inner layer substrate. In this embodiment, the substrate selected is Meteorwave1000L.

[0025] S2. A release film of a preset width is stacked on each of the upper and lower edges of the inner copper-free substrate, and then a layer of PP and a layer of copper foil are stacked on the upper and lower edges in sequence.

[0026] According to such Figure 2 The locations shown are indicated by overlapping a rectangular release film with a width of 1-2 cm on each of the upper and lower edges of the inner copper-free substrate and securing it with tape.

[0027] The type of PP is selected according to the substrate model. For Meteorwave1000L, 2116 PP is selected. The PP is also cut into 8cm×10cm sizes, and the copper foil is also cut into the same size. One layer of PP and one layer of copper foil are stacked on the top and bottom respectively. The thickness of the copper foil is 1 / 2 oz.

[0028] S3. After the stacking is completed, the sample is pressed together to obtain the template.

[0029] After the release film, PP and copper foil are all stacked, a small press is used for pressing, with the temperature set at 190 degrees, the time at 60 minutes and the pressure at 200 PSI.

[0030] During the lamination process, the following precautions should be taken: the steel plate should be ground flat before use; HOZ copper foil should be used for the outer layer of PP, with the rough side facing PP; the buffer pad should not be reused more than twice; and the number of lamination layers should not exceed 3.

[0031] S4. Take out the template of the preset size from the template obtained by pressing.

[0032] The template is obtained by pressing. A 5mm x 50mm strip is taken from the center of the template (leaving an edge of about 1.3mm. The starting point of the strip is on the release film so that the instrument can clamp it when testing the tensile strength). Two strips are taken from the top and bottom surfaces respectively.

[0033] S5. Use a tensile tester to test the tensile strength of the sample. The test result is the bonding force between the fiberglass cloth and the resin.

[0034] During the tensile testing process, the bottom of the sample needs to be bonded to the original plate with double-sided tape to prevent the middle of the sample from curling up during the test, and the pulling should start from the side with the release film.

[0035] If the minimum tensile force is greater than or equal to 3.0 Ib / in, and there is no unadheded resin within 1 cm after the starting point, then the bonding force between the fiberglass cloth and the resin is qualified.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of testing the bond strength of a glass fabric and resin, characterized by, include: The substrate is pretreated to obtain a copper-free inner layer substrate; A release film of a predetermined width is laminated on each of the upper and lower edges of the inner copper-free substrate, and then a layer of PP and a layer of copper foil are laminated on the upper and lower edges respectively. After the layers are stacked, they are pressed together to obtain a template. A template of the preset size is retrieved from the template obtained by pressing. The tensile strength of the sample was tested using a tensile tester, and the test result was the bonding strength between the fiberglass cloth and the resin.

2. The method for testing the bonding strength between fiberglass cloth and resin according to claim 1, characterized in that, The substrate is selected from those with HVLP or higher grade copper foil.

3. The method for testing the bonding strength between fiberglass cloth and resin according to claim 1, characterized in that, The pretreatment involves etching the substrate in the inner layer to create a copper-free inner layer substrate.

4. The method for testing the bonding strength between fiberglass cloth and resin according to claim 1, characterized in that, The preset width is 10~20mm.

5. The method for testing the bonding strength between fiberglass cloth and resin according to claim 1, characterized in that, The model number of the PP is 2116.

6. The method for testing the bonding strength between fiberglass cloth and resin according to claim 1, characterized in that, The copper foil has a thickness of 1 / 2 oz.

7. The method for testing the bonding strength between fiberglass cloth and resin according to claim 1, characterized in that, The spline is retrieved from the center of the template.

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