Archive for the ‘DBC substrate’ Category

How does a DPC Ceramic PCB Manufactured?

星期六, 6 7 月, 2024

Direct Plating Copper (DPC) is a ceramic circuit board developed on the basis of ceramic film processing. Aluminum nitride/alumina ceramic is used as the substrate of the circuit, and the composite metal layer on the surface of the substrate is sputtered, and the circuit is formed by electroplating and lithography. Its basic processes are:

Incoming Quality Control (IQC)

The process begins with the inspection of raw materials to ensure they meet strict quality standards. This step involves checking ceramic substrates for physical defects such as cracks, chips, or surface irregularities, and verifying material properties like thermal conductivity and dielectric strength. Advanced equipment such as microscopes and X-ray fluorescence (XRF) analyzers are used for thorough inspection, ensuring only the best materials proceed to the next stage.

Laser Drilling

Before laser drilling, a water-soluble, food-grade substrate pigment is brushed onto the ceramic substrate to reduce reflectivity and enhance laser drilling effectiveness. After drying in an oven, a laser drilling machine is used to drill through the substrate, creating pathways for connections between the upper and lower surfaces. Depending on the ceramic material, different laser wavelengths such as infrared, green light, ultraviolet, or CO2 are used to burn away the material with each laser pulse.

How does a DPC Ceramic PCB Manufactured?

Laser Marking

Laser marking involves using a laser marking machine to engrave product QR codes onto the ceramic substrate. This step ensures precise and permanent identification marks on the PCB.

Ultrasonic Cleaning

After laser drilling and marking, the substrates are cleaned to remove any attached particles or residues. This involves coarse and fine debris removal using ultrasonic cleaning, followed by water washing to eliminate any remaining particles. The cleaned substrates undergo micro-etching to roughen the surface, enhancing the effectiveness of subsequent magnetron sputtering, and are then dried to remove surface moisture.

Magnetron Sputtering

In the magnetron sputtering process, a high-vacuum chamber is used to ionize argon gas, producing an ion stream that bombards a target cathode. This causes atoms of the target material to be ejected and deposited as a thin film on the ceramic substrate. Pre-sputtering treatments such as dust removal, degreasing, and slow pulling are conducted to ensure optimal results.

Chemical Copper Plating

Chemical copper plating thickens the copper layer, improving the conductivity of the vias and ensuring better adhesion with the sputtered copper layer. This catalytic redox reaction involves pre-treatment steps like degreasing, micro-etching, pre-immersion, activation, and acceleration to ensure proper copper deposition.

Full-Panel Electroplating

Full-panel electroplating increases the thickness of the copper layer. This involves processes such as degreasing, micro-etching, acid washing, copper plating, and stripping excess copper from the fixtures. The copper plating uses copper balls as anodes and an electrolyte solution of CuSO4 and H2SO4, with the primary reaction being Cu2+ + 2e- → Cu.

Grinding, Laminating, Exposure, and Developing

Post electroplating, the copper layer is prepared for patterning. This includes acid washing to remove oxides, grinding to roughen and clean the surface, laminating with a photoresist dry film, UV exposure through a photomask to create the desired pattern, and developing to dissolve unexposed areas, leaving behind the patterned photoresist.

Pattern Plating (Electroplating Copper)

The exposed and developed areas of the substrate where the circuit pattern is defined undergo further copper electroplating to thicken the circuit traces.

Etching and Stripping

Unwanted copper and dry film are removed through etching, stripping away excess copper deposited in previous steps. This includes rough grinding, film stripping, copper etching, and titanium etching, ensuring only the desired circuit pattern remains.

Annealing

The ceramic boards are annealed in a furnace to relieve stresses introduced during electroplating, enhancing the ductility and toughness of the copper layer and ensuring dense copper grain packing.

Belt Grinding

Post-annealing, the substrate surface may have an oxide layer and rough texture. Belt grinding is used to remove these oxides and smoothen the surface, ensuring the quality of subsequent gold or silver surface treatments.

Flying Probe Testing

High-speed flying probe testers check for continuity and shorts in the vias and circuit traces, ensuring electrical integrity.

Sandblasting Before Solder Mask

Prior to solder mask application, the substrate undergoes sandblasting to roughen and clean the surface, removing oxides and contaminants. This includes acid washing, sandblasting, and micro-etching.

Solder Mask Printing

Solder mask is printed on areas of the PCB that do not require soldering, protecting the circuits during soldering and assembly. Screen printing applies solder mask ink, which is then UV-cured and developed to remove unexposed areas.

Sandblasting After Solder Mask

After solder mask application, exposed areas that need surface treatments undergo sandblasting to roughen the surface and remove oxides, preparing for gold or silver plating.

Surface Treatment

Surface treatments like electroless or electrolytic plating of gold, silver, or other metals are applied to the solder pads, enhancing solderability and preventing oxidation.

Laser Cutting

Laser cutting equipment precisely cuts the finished PCBs from the manufacturing panel, ensuring accurate dimensions and clean edges.

Testing

Various testing equipment, including thickness gauges, Automated Optical Inspection (AOI) machines, and ultrasonic scanning microscopes, are used to inspect the PCBs’ performance and appearance, ensuring they meet quality standards.

Packaging and Shipping

Finally, the PCBs are vacuum-packed using packaging machines to protect them during transport. They are then stored and shipped to customers, ensuring they arrive in perfect condition.

Above is the all the processes of DPC muanufacturing. If you are interested in process of other PCBs, welcome to contact us.

1. High thermal conductivity

The core metal content of ceramic circuit boards is as high as 96-98%, which makes them have extremely high thermal conductivity. Compared with ordinary FR4 circuit boards, the thermal conductivity of ceramic circuit boards can reach 170-230 W/mK, while the thermal conductivity of FR4 boards is usually only 0.3-0.4 W/mK. Higher thermal conductivity allows for more efficient heat dissipation, avoiding the problem of damage to electronic components due to overheating. This is particularly important in high-power applications, such as LEDs and power semiconductors.

2. Low thermal expansion coefficient

Ceramic materials have a very low coefficient of thermal expansion (CTE), usually between 6-8 ppm/°C. In contrast, FR4 material has around 14-16 ppm/°C CTE. This means that ceramic materials hardly expand or contract when temperature changes. The low thermal expansion coefficient improves the reliability of the circuit board, reduces the influence of the thermal cycle on the circuit board structure and the connection of electronic components. Especially suitable for use in the environment with frequent temperature changes.

3. High surface hardness

The surface hardness of ceramic materials is up to 9 Mohs, which is harder than aluminum oxide and silicon. It means ceramic PCB has more wear-resistant, scratch resistant, and not easy to damage. It enables to run stably for a long time even in harsh physical environments, extending the service life of the board. That is why ceramic PCB is always recommended to use in military.

4. High compressive strength

The compressive strength of the ceramic circuit board can reach 450-500 MPa, which can withstand large mechanical pressure without deformation or rupture. This characteristic makes them excellent in applications that require them to withstand mechanical stress, such as industrial automation and aerospace.

5. High dielectric strength

Ceramic PCB has very high dielectric strength, usually between 15-25 kV/mm. And it can withstand higher electric fields without electrical breakdown.

6. Ability to withstand higher temperatures

Ceramic circuit boards can operate at temperatures up to 1000°C without degradation or damage. While FR4 circuit boards typically operate at an upper limit of 140-170°C. Ceramic circuit boards are suitable for electronic devices in high temperature environments, such as electric vehicles and high-power lasers.

7. High breakdown voltage

The high breakdown voltage of the ceramic circuit board can reach 20-35 kV, ensuring reliable operation under high voltage conditions. It is well suitable for use in high-voltage power supplies and power electronic equipment, providing higher safety.

8. Does not absorb water

The water absorption of ceramic materials is usually less than 0.1%, while the water absorption of FR4 materials is 0.1-0.2%. The non-water absorbing feature prevents performance degradation and damage caused by water absorption in a humid environment. It is ideal for Marine, medical, and other applications that require moisture resistance.

9. Low loss at high frequency

In high-frequency applications, the dielectric loss Angle tangent (Df) of ceramic circuit boards is usually between 0.0001-0.001, while the loss Angle tangent of FR4 materials is 0.02-0.03. Low loss ensures signal integrity and transmission efficiency, which is suitable for communication equipment and high-frequency electronic equipment.

10. Resistance to cosmic rays

Ceramic materials can resist the impact of cosmic rays, will not be degraded or damaged by rays. They are suitable for satellite electronic equipment, ensuring the stability and reliability of the circuit board in a high radiation environment.

11. No organic ingredients

Ceramic circuit boards do not contain organic components, so they have high chemical stability, are not susceptible to chemical corrosion and decomposition. They are good choice to use in harsh chemical environments.

12. High-density assembly

Ceramic circuit boards support high-density assembly with line/pitch resolution of 20 microns. This allows them to be adapted to more complex and refined circuit designs, suitable for microelectronics and high-precision applications.

Best Technology provides professional one-stop ceramic PCB design and manufacturing service all around the world. We welcome all the friends and partners from domestic and abroad to visit our ceramic circuit board workshop.

Thick Film Ceramic PCB

Thick film technology is a process by using screen printing conductor paste and directly deposit slurry (conductor) on the ceramic substrate. Then sintering it under high temperature to form conductive circuit traces and electrodes, which is suitable for most ceramic substrates.

After the material is sintered at high temperature, a strong adhesion film will be formed on the ceramic circuit board, repeat this step for many times, a multi-layer circuit is generated.

You can print resistor or capacitor on the surface to get a interconnected structure. At Best Technology, we can make all the resistors with the same value, or different value for different resistor on the same board.

What are the different types of ceramic pcbs?

Thick film ceramic PCB has advantages on the simple manufacturing process, but it has some drawbacks that can’t be ignored:

Limited by the conductive paste and screen size
Line width less than 100um is difficult to achieved
Three-dimensional patterns are not available
Not suitable for fine-trace project

DBC / DCB Ceramic PCB

Direct Bonded Copper (DBC) or Direct Copper Bonded (DCB) ceramic PCBs are known for their excellent thermal conductivity. They are made by bonding a layer of copper directly onto a ceramic substrate, typically aluminum oxide or aluminum nitride. Due to the DBC technology is directly bond copper on the ceramic substrate, it can achieve thicker copper thickness to 300um. So, it is very suitable for high power applications.

The basic chemistry principle is to introduce an appropriate amount of oxygen between copper and ceramics before or during the application process. Copper and oxygen will form Cu-O eutectic liquid under 1065℃~1083℃. This is an important element in the manufacturing. DBC ceramic circuit board uses this eutectic solution to chemically react with the ceramic substrate to form CuAlO2 or CuAl2O4, achieving the combination between substrate and copper foil.

However, it is easy to generate micro-porosity between Al2O3 and Copper during the copper bonded process, and it doesn’t have a good solution by far. That is why the yield of DBC ceramic PCB is not good than DPC.

DPC (Direct Plated Copper Ceramic PCB)

DPC ceramic PCB utilizes direct copper plating technology, deposit copper foil on the alumina oxide (Al2O3) substrate. It is the most commonly used ceramic PCB in recent years. The circuit generated process is: pre-treatment – sputtering – exposure – develop – etch – strip – electroplating.

AMB (Active Metal Brazed Ceramic PCB)

AMB ceramic copper clad plate adopts the active brazing process, and the copper layer bonding force is higher than that of DPC, which is around 18n/mm – 21n/mm. AMB ceramic copper clad plate usually has a high binding force, usually makes thicker copper, between 100um and 800um. The AMB ceramic PCB generally rarely design traces or holes, even if there is a trace is very simple, the spacing is relatively wide.

HTCC (High Temperature Co-fired Ceramic PCB)

HTCC is a relatively early development technology, but due to the high sintering temperature (1300~1600℃), the choice of electrode materials is limited. Meanwhile, its cost is more expensive, these promotes the development of HTCC is relatively slow.

LTCC (Low Temperature Co-fired Ceramic PCB)

Although LTCC reduces the co-firing temperature to about 850 ° C, the disadvantage is that the dimensional accuracy and product strength are not easy to control.

Thin Film Ceramic Circuit Board

The thin film ceramic PCB is to deposit a metal layer directly on the surface of substrate by sputtering process. Through lithography, development, etching and other processes, the metal layer can also be graphed into a circuit pattern. Due to the low deposition speed of sputtering coating (generally less than 1μm/h), thin film substrate surface metal layer thickness is small and can prepare high pattern accuracy (line width/line space less than 10μm).

Common Ceramic Substrates

Best Technology is a leading ceramic PCB manufacturer in Asia, our core members has over 20 years manufacturing experience in ceramic PCB fabricating. “High mixed, low volume, high quality, fast delivery” is our advantages and we always try our best to do that, make ourselves better and better. If you are interested in it, feel free to contact us, we are always online.

What is Ceramic PCB?

A ceramic PCB is a type of PCB made from ceramic materials, such as alumina (Al2O3), ALN (aluminum nitride), or Beryllium Oxide (BeO). These materials are prepared by using thermal conductive ceramic powder and organic adhesive under the condition of below 250℃. Ceramic powders are not easy to made, especially for aluminum nitride powder, this is one of reasons that why ALN ceramic PCB is more expensive.

There are some different methods to make ceramic PCBs, commonly in the market are thick film, DBC, DPC and thin film technology. Different types of ceramic circuit boards have its unique characteristics. May you heard about HTCC, LTCC and AMB, they are also the ways to make ceramic PCBs, but there just a few manufacturers can make. Here is a HTCC ceramic PCB that we made.

Why Ceramic PCBs are popular used?

Different from the traditional FR-4 PCB (wave fiber), ceramic PCBs have good high-frequency properties, electrical properties that organic materials can’t achieved. It is a new generation of large-scale integrated circuits and power electronics module ideal packaging materials. The main advantages of ceramic circuit board including:

Higher thermal conductivity
More matched thermal expansion coefficient (CTE)
Lower resistance
Good weldability and can be used in high temperature
Good insulation
Lower high-frequency loss
High density assembly available
No organic ingredients, resistance to cosmic rays, high reliability in aerospace
No oxide layer in copper layer, so it can be used for a long time in a reducing atmosphere

Who is the Best Ceramic PCB Manufacturer?

There are so many PCB manufacturers in the domestic and aboard, but reliable ceramic PCB vendors with good quality and reasonable price are very few. If you are looking for an experienced one, then keep the change. We’re the best option! Best Technology offers ceramic PCBs for our customers more than 100k every year, and we are high mixed from thick film ceramic PCB, DPC ceramic PCB, DBC/DCB ceramic PCB to AMB. Your PCBs need to use in automotives? Don’t worry, we gained IATF16949 and ISO13485 certifications, and all the manufacturing processes are strictly followed by ISO9001 quality control system. We welcome all the questions and inquiries from everyone.

Here is our ceramic PCB manufacturing capability for your reference.

Ceramic PCB Manufacturing Capability
No.	Item		General Parameter	Special Process
1	Substrate	High insulation, chemical corrosion resistance, high-temperature resistance	Al2O3	Glass, quartz, sapphire, 99% , 92% Al2O3 (black)
2		Excellent thermal conductivity, low thermal expansion coefficient, and high-temperature resistance	AIN
3		Insulation performance and high-temperature stability	ZTA
4		High strength, high hardness, high thermal conductivity, and low dielectric loss	Si3N4
5		Conductor	Tungsten（LTCC/HTCC)、Au、Au&Pd、Au&Pb、Ag、Ag&Pd、Ag&Pb
6	Layer Count	DPC	Single – Double sided
7		DBC	Single – Double sided
8		AMB	Single – Double sided
9		Thick film	Single – Double sided, 4L
10		LTCC	Single – Double sided, 4L, 6L	6L – 14L
11		HTCC	Single – Double sided, 4L, 6L
12	Copper Thickness	Inner layer	/
13	Copper Thickness	Outer layer	Hoz-3oz (DPC), 3oz-12oz(DBC/AMB)
14	Dimension	Max. dimension	130*180	Larger dimension available (pass evaluation)
15		Min. dimension	2*2	Shipped in panel
16		Substrate thickness	Al2O3/AIN 0.38. 0.635, 1.0mm, Si3N4 0.25、0.32mm	>1.5
17	Surface Treatment (thickness)	OSP	0.2-0.5um	/
18		ENIG	1-3u”（Au）120-320u”（Ni）	/
19		Immersion silver	6-12u”	/
20		Immersion tin	≥1um	/
21		ENEPIG	Au 2u”, Pd 1U”, Ni 100u”	/
22		Hard gold	5-30u”（Au）、120-200u”（Ni）	/
23	Drill	Min. PTH	0.05MM	/
24		Min. NPTH	0.05MM	/
25		Max. aspect ratio (PTH PCB)	5:1	/
26		NTPH tolerance	±0.05	/
27		PTH tolerance	±0.05	/
28	Line width/ Line spacing	Inner layer	Line width≥0.1mm; Line space≥0.1mm	0.076/0.076mm
29		Outer layer	1OZ; Line width≥0.12mm; Line space≥0.12mm	0.1/0.1mm
30			2OZ；Line width≥0.2mm; Line space≥0.2mm	0.15/0.15mm
31			3OZ；Line width≥0.25mm; Line space≥0.25mm	0.2/0.2mm
32			4OZ；Line width≥0.35mm; Line space≥0.35mm	0.3/0.3mm
33			5OZ；Line width≥0.45mm; Line space≥0.45mm	0.4/0.4mm
34			6OZ；Line width≥0.55mm; Line space≥0.55mm	0.5/0.5mm
35			Thick film; Line width≥0.1mm; Line space≥0.1mm	0.076/0.076mm
36		Line width tolerance	±20%	/
37	Solder Mask (SM) /Silkscreen	Conductor	Glass glaze, medium, solder mask ink	/
38		SM color	White, black, green	Mixed color
39		Silkscreen color	White, black	Mixed color
40		Silkscreen height, width	Line width≥0.13mm; Height≥0.8mm	/
41		SM thickness	≥20um	/

What affects the cost of a PCB?

Drives the cost of PCBs are numerous, we can see from the PCB itself, for example, circuit board substrate materials, the external factors such as the manufacturing difficulties, the whole order quantities and some other special requirements that from designers.

Here, we listing some basic parameter factors which drives the whole cost of a PCB.

PCB substrate material

The substrate of PCB board refers to the material used in the non-conductor part of the circuit board, mainly FR4, glass fiber, epoxy resin, polyimide, copper, aluminum and so on. In the PCB manufacturing, glass fiber is widely used in the manufacture of double-sided circuit board and multi-layer board, while epoxy resin and polyimide are used in the manufacture of high-density multi-layer board. Among them, copper substrate is most expensive material. No matter what kind of materials, all of them shall be calculated according to the real-time international price.

PCB size (panel and single pcs)

PCB size will determine the price of PCBs, this is for sure. Generally speaking, with a same number of PCB layers, the smaller the PCB size, the cheaper the cost. Because during calculating cost, vendors will consider the utilization rate of raw materials. Make sure the highest utilization, the cost for both purchaser and vender will be best. The raw material of PCBs is commonly 1200mm*1200mm, or 1220mm for special specifications, when the utilization achieves 90% or above, this is the best.

So, how to improve the utilization of raw materials? Normally, manufacturers will optimize the working files (WF) from single size to panel size, and then material will be cut according to the panel files. But if the panel size is not suitable, then there will be a lot of waste edges of raw material in the cutting process, and generally this will be added into your PCB price. So that the unit PCB price will be more expensive. In another word, if you PCB size is well-suited, then it is good for PCB manufacturer and yourself. And at this time, the utilization will be the highest and your PCB cost is the cheapest as well.

Line width/spacing

To a certain extent, as long as you are following the PCB design rules, the PCB price will not too high. However, if your design is complex and the line width is extreme thin, then the price will increase since it is difficult to control during manufacturing.

PCB layers

According to the IPC standard, PCBs can be classified to single-layer PCB, double sided PCB and multilayer PCB. For layer count over than 2 layers, we called it as Multilayer PCBs, such as 4 layers PCB, 6 layers PCB. For FR4 PCB, we can make up to 32layers.

Due to the manufacturing process and some unpredictable assembling cycles, the more the layers, the more expensive it is. (The price of single side PCB is the similar to double sided PCBs.)

Solder mask ink color

In the past, it is no doubt that you will spend more if you want every color expect green. But now things are changeable. Most colors are available at no or very little extra cost, which usually only occurs for unique requests such as matte tones.

PCB copper foil thickness

The weight of copper foil depends on the successful utilization of the material. Thicker copper is more expensive and comes with additional manufacturing difficulties and expenses. You may also have to fill the holes with copper foil to connect layers. In addition, heavier copper means you need to spend more cost in shipping. Let’s take a simple example, for aluminum core PCB and copper core PCB, in the same volume and quantities, copper core PCB stands out for expensive shipping cost since it has thicker copper and heavier weight.

PCB surface treatment

Surface treatment is a method that using for protecting the surface from corrosion and improve the solderability. Usually, in consideration of environmental friendliness, vendors can use a couple of gold or silver to achieve further safety for use in some applications.

The commonly used surface treatment methods include OSP, IMMERSION SILVER, ENIG, ENEPIG and HASL (LF). Among them, the price is ENEPIG>ENIG>IMMERSION SILVER>OSP>HASL. You can calculate the PCB board price according to the surface treatment method and gold thickness.

Quantity and lead time

When developing a new project, almost of companies would like to make prototypes first and ask for a sample quotation. However, some PCB manufacturers will set the minimum order quantity, the smaller the quantity, the higher cost the PCB board. Please make sure to check the price for different amount before placing an official order.

Meanwhile, the delivery time request also will affect the whole price in a certain. And certainly, the price of quick turn order and expedited service will higher than normal order.

Other special requirements (impedance, IPC standard)

To ensure the stable transmission of circuit board signals and improve the quality of signal transmission, designers and engineers will ask for impedance control for the traces. This can be seen as special requirements, so it will add a few extra prices. And the required IPC Criteria is a factor as well. Normally, if customer does not have other request, we will default use IPC class II. III level will more expensive.

Above all are the mainly factors that affect the price composition for a printed circuit board. When evaluating your PCB cost, making them in your consideration is best.

PCB and PCBA supplier that can save cost for you – Best Technology

When you are seeking for a reliable PCB and PCBA supplier, I would like to recommend Best Technology to you. Best Tech offers one-stop service including raw material purchasing, PCB making, components searching, assembly, box building and package out of warehouse. What we can provide is not limited to PCB, but also metal core PCB, ceramic PCB, flexible PCB, rigid flex PCB, special PCB like HDI PCB, heavy copper PCB, extra thin PCB and so on. During the 17 years, the Best Technology company has served include medical industry, consumer electronics, new energy, automotive electronics, aerospace, military and others.

Could it be said that you are searching for a PCB supplier that can provide favorable price that lower than market? If this is true, please go ahead and reach us today, let’s talk about more PCB information right now and start our business trip together. We promise, when you decide to take the first step, and we’ll take the remaining 99 steps.

What Ceramic Metallization Technology Is?

Ceramic metallization refers to the process of firmly attaching a thin layer of metal film to the surface of a ceramic material to achieve a bond between the ceramic and metal. There are various methods for ceramic metallization, commonly including molybdenum-manganese (Mo-Mn) method, directly copper plate (DPC), directly bonded copper (DBC), active metal brazed (AMB) method and more.

Which Ceramics Can Be Used Metallization Technology?

At present, there are four common ceramic substrates that always used for metallization, they are BeO, Al2O3, AlN and Si3O4. But different ceramic has different characteristics, so its metallization method also is different.

BeO Ceramic

The most common method for metallizing BeO ceramics is the Mo-Mn method. This involves applying a paste-like mixture of pure metal powders (Mo, Mn) and metal oxides to the ceramic surface, followed by high-temperature heating in a furnace to form a metal layer.

Al2O3 Ceramic

The primary metallization methods for Al2O3 ceramics are DBC and DPC. This method involves placing a treated copper foil on the surface of Al2O3 ceramics, introducing an inert gas with a certain oxygen content, and then heating. During heating, the copper surface undergoes oxidation, and when the temperature reaches the eutectic liquid phase region, a eutectic liquid phase is formed, wetting both Al2O3 ceramics and copper, achieving a tight bond. In a chemical sense, the adhesion used by DBC is stronger than DPC since it has thicker copper.

AlN Ceramic

Common methods for AlN ceramics include DBC and Active Metal Brazing (AMB). DBC is similar to the method used for Al2O3 ceramics but requires pre-oxidation treatment of AlN ceramics since AlN is a non-oxide ceramic. AMB involves connecting AlN ceramics and copper foils using active metal brazing materials, often Ag-Cu-Ti alloys.

Si3N4 Ceramic

Si3N4 ceramics cannot be directly metallized using the direct copper plating method because they do not generate an oxide layer on the surface like AlN ceramics. Si3N4 ceramics are typically connected to metals using the AMB method, where chemical reactions between Si3N4 and active metals (Ti, Cr, V) form continuous nitride layers at the interface.

What is the Metallization Temperature?

During the metallization process, the sinter temperature should be controlled strictly. Normally, it can be divided into four ranges:

Ultra-High Temperature (Above 1600°C):

This temperature range is reserved for specific applications where extreme heat resistance is required.

High Temperature (1450°C to 1600°C):

High temperatures are essential to ensure that the glass phase spreads and migrates effectively, enabling a strong bond. However, excessively high temperatures can lead to reduced metallization strength.

Mid-Temperature (1300°C to 1450°C):

This range is chosen to balance the need for effective metallization with the preservation of material properties.

Low Temperature (Below 1300°C):

Lower temperatures are used when the primary concern is avoiding thermal stress on the materials involved.

Proper high sintering temperature is necessary, otherwise, the glass phase will not spread and migrate. But if the temperature is too high, the metallization strength will be poor. So, choose a suitable temperature is important to make sure the metallization effective.

This is all the information about metallization technology, in our next blog, we will delve into what factors will affect the metallization. If you are interested in metallization or other technologies about ceramic circuit boards, please leave your message and keep your eyes in Best Technology website.

Oxidation technology of copper foil

Copper oxidation is divided into Wet Air Oxidation (including soaking oxidation and spraying oxidation) and Dry Oxidation. Both oxidation methods can form CuO or Cu2O on the surface of copper foil.

Wet Air Oxidation (WAO)

i. Soaking oxidation

First, the copper is pickled with 3% dilute sulfuric acid, and then washed by the spray washing machine after overflow. Next, sent the copper into the mixed solution of potassium permanganate and copper sulfate (the concentration of potassium permanganate is about 31.6mg/L and the copper sulfate is about 95.4mg/L) for soaking and oxidation. The oxidized copper is then washed with water and three-stage countercurrent washing, and then slowly pulled for dehydration and drying (the temperature is about 100℃) to complete soaking and oxidation.

ii. Spraying oxidation

Spraying oxidation is a kind of WAO, only the oxidation method become spraying. Spray oxidation is to spray copper with mixed solution of manganese nitrate and copper nitrate (concentration of about 3%) after pickling and washing. The sprayed copper is dried directly in the tunnel kiln (the temperature is about 200℃). In the drying process of tunnel kiln, the manganese nitrate and copper nitrate sprayed on the copper sheet are decomposed into copper oxide and manganese oxide. The ratio of soaking oxidation and spraying oxidation treatment of copper sheet is about 5:5.

Dry Oxidation

Dry oxidation is very easy to process, put the copper into oxidation oven firstly, then heating up to 600~800^oC for oxidizing around 30mins and then subjected to air cooling annealing.

Wet Air Oxidation VS Dry Oxidation

At present, the existing industry is widely used to finish the high-temperature annealing oxidation of copper then sintering with ceramic substrate, that is dry oxidation. But this high temperature annealing, oxidation in one way has some drawbacks as following:

Uneven oxidation. It will directly cause sintering defects during sintering, and the peeling strength will change greatly.
Leaving conveyor belt marks. Because the high temperature and oxidation process is transported by the conveyor belt, the existence of the conveyor belt mesh will affect the temperature distribution of the entire copper is not uniform, leaving marks/traces of the conveyor belt. The result of sintering is to leave the corresponding trace on the bonding surface of CuAl2O3.
High temperature annealing and oxidation will accompany the grain growth of copper. In the subsequent sintering process, the grain will continue to grow, which brings adverse effects on the mechanical properties and surface treatment of copper. The copper surface grain produced by wet oxidation is fine, which is conducive to improving the mechanical properties of copper and eliminating the traces of conveyor belt. The main difference between wet oxidation and dry oxidation is shown in the bending resistance, heat resistance cycle performance and peeling strength, and these three indicators are significantly better than dry oxidation. Wet oxidation products can better meet the requirements of bending strength and heat resistance cycle performance.

So, this is the end of this post, Best Technology specialized in fabricating ceramic PCB (including DBC, DPC, AMB, HTCC and LTCC technology) for more than 16 years, we have rich engineering team and professional sales team can provide one-stop service for you. Welcome to contact us if you have any inquiries about ceramic PCB.

Archive for the ‘DBC substrate’ Category

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1. High thermal conductivity

2. Low thermal expansion coefficient

3. High surface hardness

4. High compressive strength

5. High dielectric strength

6. Ability to withstand higher temperatures

7. High breakdown voltage

8. Does not absorb water

9. Low loss at high frequency

10. Resistance to cosmic rays

11. No organic ingredients

12. High-density assembly

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Thick Film Ceramic PCB

DBC / DCB Ceramic PCB

DPC (Direct Plated Copper Ceramic PCB)

AMB (Active Metal Brazed Ceramic PCB)

HTCC (High Temperature Co-fired Ceramic PCB)

LTCC (Low Temperature Co-fired Ceramic PCB)

Thin Film Ceramic Circuit Board

Common Ceramic Substrates

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What is Ceramic PCB?

Why Ceramic PCBs are popular used?

Who is the Best Ceramic PCB Manufacturer?

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What affects the cost of a PCB?

PCB and PCBA supplier that can save cost for you – Best Technology

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What Ceramic Metallization Technology Is?

Which Ceramics Can Be Used Metallization Technology?

What is the Metallization Temperature?

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Oxidation technology of copper foil

Wet Air Oxidation VS Dry Oxidation

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