Via last vs Via Middle

Common characteristic:
1.DRAM+interposer are already bonded (hybrid bond) before TSV
2.TSVs Cu embedded before incoming

Via last flow
i)BSG:BG-->Backside CVD-->PR litho
ii)TSV formation: TSV etch-->Linear deposition-->Etch-->TSV TiCu deposition
iii)RDL-->PI-->UBM-->C4 bump-->Dicing

1.TSV is etched after wafer thinning(435+12.5+50)
2. TSV depth is shorter(interposer 50um)

Via middle flow:
i)Early thinning & oxide: Wafer trim-->BG-->CVD oxide-->BG/Si CMP
ii)TSV reveal+TSV dielectric:TSV reveal etch-->TSV CVD-->Oxide CMP
iii) Bump : PVD TiCu-->PI PSV-->ECD Cu/SnAg-->reflow
iv)Final front side Grind-->Dicing

*TSV &bump is processed on thicker wafer (775+12.5+108um)

A Day of Fighting a Cold

 Over the past few days, I have not been feeling well. I developed a runny nose, my heart was beating faster than usual, and my body felt unusually warm at night while I was sleeping. These symptoms were also reflected in the data recorded by my Apple Watch, which made me even more concerned. I worried that my condition might worsen and turn into a cough in the coming days.

Because of this concern, I woke up earlier than usual today and went to the market to buy lemons and kumquats, hoping to strengthen my body with more vitamin C. After searching online, I learned that drinking coffee could cause dehydration, so I decided to give up my morning coffee and put it away in the refrigerator.

In the evening, after a meeting with my process team, I shared my condition with a colleague. He kindly gave me a packet of Japanese cold medicine to help relieve my symptoms. To my surprise, the medicine worked much faster and more effectively than the lemons and kumquats. Within thirty minutes of taking it, my runny nose completely stopped.

I felt deeply relieved and grateful. Thanks to my colleague’s kindness and the effectiveness of the medicine, my condition improved quickly. I thanked God for this small but meaningful recovery and hoped that my health would continue to improve in the coming days.

My Feelings About the Fall of President Maduro

When I heard the news about President Maduro being captured, my first reaction was a deep sense of relief. For many people, this may simply be another political headline, but for me, it is closely connected to the lives and suffering of my friends from Venezuela. Over the years, I have listened to their stories of economic collapse, fear, and hopelessness. Because of them, Venezuela is not just a country on the news—it is a place filled with real people I care about.

Under Maduro’s leadership, Venezuela’s economy deteriorated dramatically. Even well-educated professionals such as pharmacists and teachers struggled to survive. The value of the currency dropped so severely that ordinary citizens could no longer afford basic necessities. My friends told me about shortages, insecurity, and the constant stress of not knowing what tomorrow would bring. Hearing these experiences made me feel angry and helpless, as no government should allow its people to live in such conditions.

One of my close friends was a pharmacist in Venezuela, a profession that should have provided dignity and stability. However, she was forced to leave her country in order to have a chance at a normal life. Even though she now works in a position far below her qualifications, she lives with more safety and peace than she ever did back home. This reality deeply shaped my view of the Maduro government.

Because of this, I feel hopeful that Venezuela may finally have an opportunity for change. I sincerely wish that my friends who remain there can live safely, freely, and happily in the future. If international involvement—especially from the United States—can help restore stability, order, and economic recovery, then I hope it will lead Venezuela toward a better path. Above all, my wish is simple: that Venezuelan citizens can live without fear, with dignity, and with hope for tomorrow.

Bad habit and change

 A few years ago, I developed a bad habit without realizing it at first. I became somewhat addicted to alcohol. I used to tell myself that drinking was only for the weekend, a way to relax and help me fall asleep after a long week. At the beginning, it felt harmless and even comforting.

Over time, however, I noticed that I was depending on alcohol more than I should. Relaxation started to feel impossible without it. That was the moment I understood that this habit was no longer a choice—it was becoming a reliance.

I decided to make a change in a very simple but firm way. I stopped buying alcohol and made sure there was none in my refrigerator. By removing the temptation from my daily environment, I gave myself fewer chances to give in. At first, it was uncomfortable, and weekends felt strange without my usual routine. But gradually, my body and mind adapted.

Looking back, I am proud of this decision. Breaking a bad habit does not always require dramatic actions; sometimes it starts with a small, clear rule and self-discipline. This experience taught me that real relaxation comes from a healthy mind, not from escaping reality. It also reminded me that I am capable of changing when I truly decide to do so.

My precious baby Lingling

    I have a 13-year-old female Shiba Inu from Japan. She is old now, but she is still my precious baby. She has been spoiled her whole life, and I am happy to let her be. Every day, I carry her up and down the stairs just so she can go outside for a short walk. My arms or legs get tired, but my heart never complains.

    At mealtime, she eats with caution, constantly watching Amu, afraid he might steal her food. She eats quickly, nervously. And if the food is not enough, she barks at me again, trusting that I will understand her needs. She trusts me completely.

    Every night, after eating her dinner, she will bark at me again around midnight, asking for more food. Even when I pretend to be asleep, she knows. Her small barks are demanding, but they are also a reminder that she is still here, still hungry, still full of life.

    She needs a dog bed everywhere—one in the bedroom, one in the living room, and even one in my landlord’s room. Every place must have her own bed, as if she wants to leave her presence behind wherever she rests. When Amu, the Husky my landlord raises, takes her bed, she never blames him. Instead, she looks at me with angry eyes, as if saying, “Why didn’t you protect what belongs to me?” She is smart like that. She always knows who to blame.

    Last month, she became sick and was diagnosed with gastroenteritis after blood tests and an X-ray. The veterinarian told me she has many bone spurs around her spine. Hearing that broke my heart. Thankfully, I have been giving her Antinol regularly to ease her pain. The doctor praised me for taking good care of her and said that because of this, she can still walk properly. If she had not received this care, she might have become paralyzed suddenly.

I realized then how fragile her time is, and how precious every ordinary day has become. Carrying her, feeding her, listening to her bark—it is all love. As long as she needs me, I will be there.

Is it worth being married?

Today marks a new beginning, the first day of 2026. I find myself thinking seriously about marriage and whether raising a child is realistic in this generation, especially with my current income of about NTD 60,000 per month after tax.

When I look at my finances honestly, I know my resources are not abundant. Raising a child means endless expenses—food, childcare, school fees, and extra tutoring. Just imagining these costs already feels heavy. It’s hard to feel confident about the future when everything seems to require more money than I can comfortably afford.

I also think about marriage. If I were to marry, there seems to be an unspoken rule that the man should earn more than I do—maybe at least NTD 100,000 a month—to live a stable and comfortable life. But a higher income often comes with higher expectations. His family might expect regular visits during Lunar New Year and every major festival. There would be family gatherings, preparations, cooking, and gifts. If someone in his family became ill, I might be expected to take care of them, too. These responsibilities feel overwhelming when I imagine them becoming part of my everyday life.

Then there is the question that troubles me the most: the future. If I raise a child and they grow up, will they take care of me when I am old? In my mother’s generation, children naturally carried the responsibility of caring for their parents. But in this generation, shaped so strongly by the internet and individual freedom, nothing feels guaranteed anymore. People are no longer expected to sacrifice their lives for their parents, and I don’t know if it is fair—or realistic—to expect that kind of devotion.

Thinking about all of this, I feel that marriage and having children are no longer simple life milestones. They are complicated decisions filled with uncertainty, responsibility, and quiet fear. At the beginning of 2026, I don’t have clear answers—only questions that stay with me longer than I expected.

Reflow soldering process

 Solder paste is used to temporary attach to the anywhere to all the contact pads, after which the assembly is subjected to the controlled heat. Solder paste reflows in a molten state, creating permanent solder joints. Heating can be accomplished by passing the assembly, through a reflow oven.

Usually four stages: preheat,thermal soak, reflow, heating

Preheat zone: climb towards to a target soak, dwell temperature.

Why lead free?

1. Health care

2. Environment: To align with RoHS with the European Union

Tin frequently serves as a principle solder due to its low melting point and excellent wetting properties. Cu & Ag are sometimes added to enhance mechanical strength, and electrical properties of the solder. 

-->Lead based solder: Tin-60%, Pb-40%, melting point:188oC

 -->Lead free Solder: Sn-Ag-Cu, >95% Tin, melting point: 227oC, but less ductile than lead based solder, rendering it has susceptible to mechanical stress, tends to be oxidize more rapidly which can adversely affect its wetting properties and solder joint quality.

What is soldering

A process involves solder, to join together metal surfaces. The solder is heated until it melts and flows into the joint between the two surfaces. Upon cooling, it hardens and forms a reliable electrical and mechanical connection.

Before soldering, the surface of metal should be cleaned thoroughly to remove any oxidations or contaminations that could interfere the formation of a good solder joint.

Vaccum effectively reduce solder void in soldering process

Siemens-EDA Summary

A.Calibre 3D thermal

1.placement & stacking analysis

2.thermal verification :power map 

Simcenter Flotherm : golden tool for 3D thermal simulation & exporting 3D thermal results

Ease of use, designer friendly use, speed, high accuracy providing color maps in 1 day. From simplified power map to final design with detailed power & GDS inputs.

Accuracy: the worst-case difference between simulation and the measured data :3.75%

Customer experince: UMC, TSMC, Intel

B. 3Dblox

Unified format and standardized language

from introduce chiplet detail information, top down to confirm connectivity

C. DFT

scalable from 2D to 3D

die integration & dies at package level

test between dies after AP & diagnosis(in

Complaint with IEEE1149.1, IEEE1500, IEEE1838

Tessant: serial access port composed PTAP/STAP

die wrapper register (DWR) for dies isolation

HBM usually come with IEEE1500 interface, helps to validate the speed of SOC, HBM

bump map, probe map, spacing, die to die , bump analysis, repair method

D: Innovator XPD

macro complex data 

physical reuse- HBM net, auto-replacement, function: rotate, mirror,

original separately process, 500,000 pin can be processed in short time period

tuning in real time, 75% cycle time reduction

 新光電気工業の登録です。    本製品に関する特許も取得しております

チップや能動。受動部品を内蔵した

独自の半導体パックージグ技術を駆使し、優れ電気特性と高い

信頼性を備えた小型　低背パックージとして、小型

iTHOP preshrinkage issue

 The actual shrinkage rate of iTHOP is higher than anticipated, influenced by the smile warpage behavior. The inspection of iTHOP from mark to mark distance was validated that its value is smaller than actual design value. 

Based on our observation, the larger warpage , longer distance between mark to mark, which exhibits more expansion which was validated by the stage DOE experiment from Shinko & PTI. The inner flip chip pad showed that it has higher shrinkage rate, making alignment with the bumping from HBM side challenging.

The thinner organic interposer is more likely to be influenced by the properties of interposer material, it tend to be expand more freely even though vacuumed by the stage, but once bonded, it will be more easily pulled and conformed by ABF substrate.

-->Understanding the interactions can help in optimizing the design to achieve the desired alignment.

3D X ray imaging analysis request

 Since the expansion of substrate during heating with TCB bonding method, different temperature bonding have been studied to reduce the misalignment issue. The effect of temperature is limited, based on 2D X-ray imaging results showed that the farther away from the center, the misalignment value is worsen. We need further analysis with 3D X-ray to analysis if any voids, solder crack after TCB bonding