Comparison between Blind Via and Buried Via in Manufacturing of Printed Circuit Boards

Overview

The world of PCB design manufacturing extensively uses two terminologies i.e. blind via and buried via. What are these vias and how they are important and have significant role in PCB manufacturing both for consumers and the manufacturers and how these terms are different from each other are discussed in this article. Also, this article will put some light on other via types i.e. stacked via and micro via. Before understanding these vias, it is important to understand “via” in PCB design manufacturing.

 

Description of Via

In PCB designing the term “via” is extensively used. It is actually the connection source in the form of copper-plated hole which connects different layers in the PCB. Different vias can be used but the most widely standard via used across the world in every PCB is the through-hole via. Several disadvantages are associated with through-hole via specifically in surface mount technological applications. Because of these disadvantages, through-hole vias are replaced by two additional vias such blind via and buried via. Both these vias (blind and buried) have processing in a variety of different measuring features which include plugged copper mask via, plugged solder mask via, plated via and staggered via. A simple comparison of through-hole via, blind via and buried via is depicted in Figure below.

Blind Via and Buried Via

 

Blind Via vs Buried Via

Both blind and buried vias are used for connection of different PCB layers. What are the major differences in these types of vias are discussed in this section? The blind via provides an interconnection of the outer layer with a single or multiple inner PCB layers whereas only inner layers are interconnected in the buried via and the board is completely kept hidden and invisible from external environment of the PCB. Both these vias have great advantages in HDI PCBs due to their optimal density deprived of increase in the size of board or requiring the number of layers in the PCB board.

 

There is another classification of PCB board via and known as stacked via and micro via. These are discussed in the next section along with their pros and cons.

 

The stacked via is basically meant for improving further the size and density of PCBs during the process of their manufacturing. These two factors have great importance in todays’ modern miniaturizing and high transmitting signaling with requirements of speed in several applications and areas. If there is a consideration of blind via having a 1:1 or more aspect ratio or the process of drilling requires multiple layers to cover then the best way to get the interconnection among the layers  can be stacked via. Additionally, the lamination of stacked via is either by blind or buried for building multiple layers within the circuit board to be built together around the same origin or central point whereas there is no lamination around the center in the staggered via.

 

Several advantages are associated with the stacked via such as providing greater space in the board by saving the area, enhances the overall density, better in terms of flexibility in terms of internal connection, capacity of better routing and minimum parasitic capacitance. Similarly, the most important and bigger disadvantage of stacked via is their highest cost as compared to the standard through-hole via or blind and buried via that significantly reduces their use by common or student designers and favorite among the people working in bigger professional environments.

Blind Via and Buried Via

 

Similarly, there is another kind of via known as micro via which is comparatively smaller than other types of vias. This type of via is the favorite among PCB designers due to smaller diameter, greater space for routing on the PCB board and have lower parasitic capacitance in high-speed circuits and systems.  Nevertheless, there are some disadvantages of micro via such as needing more time for drilling and off-center via moves. As per the rules of RayPCB, the diameter of the micro via is kept as lower as 0.1 mm in PCB designing boards.

 

Contact RayPCB for PCBs with Blind/Buried Vias and Stacked Vias/Micro vias

RayPCB is one of the most leading PCB board designing manufacturing company that have several years of experience in designing the PCBs using both the blind and buried vias. This is the company which builds the PCB circuits based on the via types as per recommendation, desires and needs of the users for specific applications. In Table 1, the design parameters for PCB board by RayPCB using both the blind and buried vias are briefly explained and depicted along with the needs and applications.

 

Difference Between Via Type and Via Diameter

Figure 3 shows a difference between the most important design parameters provided by the RayPCB. These two important parameters are via type and via diameter. Figure 3 clear mentions via pad, via diameter and annular ring of a specific PCB layout design using the specific via based on its application.

Blind Via and Buried Via

 

The table below is illustrating different types of vias. The table is alos having information of the various dimensions necessary for the vias to be implemented in the printed circuit boards. Moreover, aspect ratio is also mentioned against each type of via.

Blind Via and Buried Via

RayPCB provides a continuously check and balance and information about the PCB design manufacturing using the particular via types. There is access to consumers for knowing the information their needs and interests to learn about the various via types. The users should get in touch for understanding the trends in via types for optimizing the value of desired PCB boards. The user can get access to the specific printed circuit just by clicking on the link given below.