Device and method for measuring thickness of dielectric layer in circuit board

The present invention relates to a device and a method for measuring a thickness of a dielectric layer in a circuit board, and more particularly to the device and the method for measuring the thickness of the dielectric layer in the circuit board including a light source and a lens module.

Currently, the thickness of the dielectric layer of the circuit board is mainly measured by destructive methods. For example, partial circuit board must be removed to be a measuring slice, firstly. Next, using optical microscope or scanning electron microscope to measure the thickness. However, such prior art is very time-consuming and labor-intensive, and it will also damage a larger area of the circuit board and cause the circuit board to be scrapped.

Therefore, how to measure the thickness of the dielectric layer in the circuit board quickly and easily is worth considering for person having ordinary skill in the art.

The objective of the present invention is to provide a method for measuring a thickness of a dielectric layer in a circuit board. The method for measuring the thickness of the dielectric layer in the circuit board can quickly and easily measure the thickness of the dielectric layer in the circuit board without damaging the circuit board.

The method for measuring the thickness of the dielectric layer in the circuit board in the present invention includes the following steps.

First, a circuit board including at least one dielectric layer and at least two circuit layers is provided. The dielectric layer is between the circuit layers, and the circuit board further includes a test area. The test area includes a test pattern and a through hole. The test pattern includes at least two metal layers. The metal layer is a part of the circuit layer. The side surface of the through hole includes a section of the dielectric layer and a section of the metal layer.

Next, a measuring device including a main body, at least one light source and a lens module is provided. The light source and the lens module are on the main body. The main body is moved into the through hole. When the main body is moved into the through hole, the light source emits light to the dielectric layer and the metal layer, and the lens module shoots the dielectric layer and the metal layer to form a captured image. The thickness of the dielectric layer is obtained via the captured image.

In the method for measuring the thickness of the dielectric layer in the circuit board, the light source and the lens module are on the same side of the main body.

In the method for measuring the thickness of the dielectric layer in the circuit board, a number of the light sources is plural, and the light sources and the lens module are at one end of the main body, and the lens module is surrounded by the light sources.

In the method for measuring the thickness of the dielectric layer in the circuit board, the light source is a light emitting diode.

In the method for measuring the thickness of the dielectric layer in the circuit board, the lens module is a CCD lens module or a CMOS lens module.

Another objective of the present invention is to provide a measuring device. The measuring device can quickly and easily measure a thickness of a dielectric layer in a circuit board without damaging the circuit board.

The measuring device of the present invention is used to measure a thickness of a dielectric layer of a circuit board. The circuit board includes at least one dielectric layer and at least two circuit layers. The dielectric layer is between the circuit layers. The circuit board further includes a test area. The test area includes a test pattern and a through hole. The test pattern includes at least two metal layers. The metal layer is a part of the circuit layer. The side surface of the through hole includes a section of the dielectric layer and a section of the metal layer. The measuring device includes a main body, a light source and a lens module. The main body is moved into the through hole, and the light source and the lens module are on the main body. When the main body is moved into the through hole, the light source emits light to the dielectric layer and the metal layer, and the lens module shoots the dielectric layer and the metal layer to form a captured image.

In the measuring device, the light source and the lens module are on the same side of the main body.

In the measuring device, a number of the light sources is plural, and the light sources and the lens module are at one end of the main body, and the lens module is surrounded by the light sources.

In the measuring device, the light source is a light emitting diode.

In the measuring device, the lens module is a CCD lens module or a CMOS lens module.

In the measuring device, a number of layers of the metal layer is plural.

The present invention has the following advantages:

Only by forming a through hole in the pre-set test area, the measuring device can be moved into the through hole to shoot the dielectric layer of the circuit board. The required area of the circuit board is small, and the circuit board will not be damaged.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

FIG. 1 illustrates a schematic diagram of a method for measuring a thickness of a dielectric layer in a circuit board of the present invention;

FIG. 2A illustrates a schematic diagram of a partial section of a circuit board 10 ;

FIG. 2B illustrates a schematic diagram of a measuring device 8 ;

FIG. 3A illustrates the schematic diagram of the measuring device 8 being about to enter a through hole 10 H;

FIG. 3B illustrates the schematic diagram of the measuring device 8 moving into the through hole 10 H;

FIG. 3C illustrates the schematic diagram of a captured image 8 P; and

FIG. 4 illustrates the schematic diagram of a measuring device 8 ′ of another embodiment.

Please refer to FIG. 1 . FIG. 1 illustrates a schematic diagram of a method for measuring a thickness of a dielectric layer in a circuit board of the present invention. The method for measuring the thickness of the dielectric layer in the circuit board in the present invention includes the following steps.

First, please refer the step S 1 and FIG. 2A . FIG. 2A illustrates a schematic diagram of a partial section of a circuit board 10 . A circuit board 10 including three dielectric layers 12 and four circuit layers 13 is provided. However, person having ordinary skill in the art should understand that in practice, the circuit board 10 may include more dielectric layers 12 and circuit layers 13 , or the circuit board 10 may only include one dielectric layer 12 and two circuit layers 13 . Moreover, the dielectric layer 12 is between the two circuit layers 13 .

In addition, the circuit board 10 further includes a test area 10 T, and the test area 10 T includes a test pattern 102 and a through hole 10 H. The test pattern 102 includes at least two metal layers 1022 . The metal layer 1022 is a part of the circuit layer 13 . In detail, in the manufacturing process of the circuit board 10 , the metal layer 1022 and the circuit layer 13 are formed at the same time, so the number of layers of the metal layer 1022 in the embodiment is the same as the circuit layer 13 in four layers. In the embodiment, the side surface of the through hole 10 H includes a section of the dielectric layer 12 and a section of the metal layer 1022 . In other words, the dielectric layer 12 and the second conductor 1022 are appeared on the side surface of the through hole 10 H.

Next, please refer to the step S 2 and FIG. 2B . FIG. 2B illustrates a schematic diagram of a measuring device 8 . A measuring device 8 is provided. The measuring device 8 includes a main body 80 , a light source 81 and a lens module 82 . The light source 81 is such as a light emitting diode (LED). The lens module 82 is such as a charge coupled device (CCD) lens module or a complementary metal-oxide-semiconductor (CMOS) lens module. The light source 81 and the lens module 82 are on the same side of the main body 80 . The main body is moved into the through hole.

Next, please refer to the step S 3 and FIG. 3A to FIG. 3C . FIG. 3A illustrates the schematic diagram of the measuring device 8 being about to enter a through hole 10 H. FIG. 3B illustrates the schematic diagram of the measuring device 8 moving into the through hole 10 H. FIG. 3C illustrates the schematic diagram of a captured image 8 P. When the main body 80 is moved into the through hole 10 H, the light source 81 emits light to the dielectric layer 12 and the metal layer 1022 , and the lens module 82 simultaneously shoots the dielectric layer 12 and the metal layer 122 to form a captured image 8 P. During the shooting process, the lens module 82 can shoot a plurality of the dielectric layers 12 and the metal layers 1022 at a time to form the captured image 8 P. Alternatively, the lens module 82 can also shoot the dielectric layers 12 and metal layers 1022 in stages from top to bottom to form photos, and then merge the photos to form the captured image 8 P in a post-production.

Because the material of the metal layer 1022 is metal, it has a higher light reflectivity than the dielectric layer 12 . Thus, the thickness of each dielectric layer 12 can be calculated via the bright part and dark part formed by the contrast difference of light reflection between the metal layer 1022 and the dielectric layer 12 in the captured image 8 P. Therefore, compared to the traditional method of measuring the thickness of the dielectric layer of the circuit board, the method for measuring the thickness of the dielectric layer in the circuit board in the present invention can quickly and easily measure the thickness of the dielectric layer in the circuit board without damaging the circuit board.

Please refer to FIG. 4 . FIG. 4 illustrates the schematic diagram of a measuring device 8 ′ of another embodiment. In the embodiment of FIG. 4 , a number of the light source 81 ′ of the measuring device 8 ′ is plural. The light sources 81 ′ and the lens module 82 ′ are at one end of the main body 80 ′, and the lens module 82 ′ is surrounded by the light sources. During the shooting process, the lens module 82 ′ shoots the dielectric layer 12 layer after layer to form photos, and then merges the photos to form the captured image 8 P in a post-production.

In summary, the present invention only needs to form a through hole 10 H in the pre-set test area 10 T, the measuring device 8 or measuring device 8 ′ is able to move to the through hole 10 H to measure the thickness of the dielectric layer 12 of each layer in the circuit board 10 , since the required area to be tested is small and conveniently tested. Therefore, compared to the prior arts, the present invention can quickly and easily measure the thickness of the dielectric layer in the circuit board without damaging the circuit board.

Although the description above contains many specifics, these are merely provided to illustrate the invention and should not be construed as limitations of the invention's scope. Thus, it will be apparent to those skilled, in the art that various modifications and variations can be made in the system and processes of the present disclosure without departing from the spirit or scope of the invention.