# US 2024/0201252 A1 · Eop probing on multi-die stacks

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- Number: US 2024/0201252 A1
- Document ID: US20240201252A1
- Status: Published application
- Kind: A1
- Application number: 18/535,640
- Filed: 2023-12-11
- Published: 2024-06-20
- Earliest claimed: 2022-12-20
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: John M. Gonzales; Seth A. Eichmeyer; Atsuko Otsuka; Takeshi Kaku; Soeparto Tandjoeng
- Web page: https://patentgrep.com/patent/US20240201252A1

## CPC

- G01R 31/311: of integrated circuits {(G01R31/31728 takes precedence)}
- H10W 90/284: {characterised by structural arrangements for measuring or testing}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

An example method can include focusing a light source onto a circuit of a first memory die of a plurality of memory dies. A light of the light source can reach the circuit of the memory die and can be reflected back toward a sensor. The method can further include receiving the reflection of light from the circuit at the sensor. The method can further include determining whether the circuit is transferring a particular signal based on the reflected light.

## Claims

### Claim 1

An apparatus, comprising:
a plurality of memory dies arranged in a stack, the plurality of memory dies each including a group of memory cells;
wherein:
each of the plurality of memory dies comprise a plurality of metallization layers; and
at least two of the plurality of memory dies comprise an area devoid of their respective plurality of metallization layers and the portion of each of the at least two of the plurality of memory dies are physically in line and perpendicular to an outside surface of the stack.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein a circuit is positioned opposite the outside surface of the stack and the devoid area of the at least two of the plurality of memory dies are between the circuit and the outside surface.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein a distance between the circuit and the outside surface is correlated with a particular size lens.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein the particular size lens is configured to focus a light source onto the circuit.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the light source is a high intensity light (HIL) source.

### Claim 6 (depends on 3)

The apparatus of claim 3, wherein the particular size lens is a solid immersion lens (SIL).

### Claim 7

An apparatus, comprising:
a plurality of memory dies arranged in a stack, the plurality of memory dies each including a group of memory cells;
wherein:
each of the plurality of memory dies comprise a plurality of metallization layers; and
a plurality of diodes are coupled to the plurality of metallization layers; and
a first diode of the plurality of diodes is coupled via at least one of the plurality of metallization layers to a second diode of the plurality of diodes such that the second diode is a particular distance from any of the plurality of diodes.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the second diode is configurable to be deactivated while the first diode is enabled.

### Claim 9 (depends on 7)

The apparatus of claim 7, wherein a first signal transferred through the first diode occurs simultaneous with a second signal transferred through the second diode.

### Claim 10 (depends on 7)

The apparatus of claim 7, wherein the particular distance is greater than 200 nanometers.

### Claim 11

A method, comprising:
focusing a light source onto a circuit of a first memory die of a plurality of memory dies, wherein a light of the light source reaches the circuit of the memory die and is reflected back toward a sensor;
receiving the reflection of light from the circuit at the sensor; and
determining whether the circuit is transferring a particular signal based on the reflected light.

### Claim 12 (depends on 11)

The method of claim 11, wherein a light of the light source passes by a second memory die of the plurality of memory dies to reach the circuit of the memory die.

### Claim 13 (depends on 11)

The method of claim 11, wherein the light passes through a devoid area of the second memory die.

### Claim 14 (depends on 13)

The method of claim 13, wherein the devoid area is created by positioning a plurality of metallization layers of the plurality of memory dies such that the light passes through the second memory die.

### Claim 15 (depends on 11)

The method of claim 11, wherein the light source is a high intensity light (HIL) source.

### Claim 16 (depends on 11)

The method of claim 11, wherein a distance between the circuit and the outside surface is correlated with a particular size lens and the particular size lens focuses the light source.

### Claim 17 (depends on 11)

The method of claim 11, wherein each of the plurality of memory dies comprise a plurality of metallization layers.

### Claim 18 (depends on 17)

The method of claim 17, wherein a plurality of diodes are coupled to the plurality of metallization layers.

### Claim 19 (depends on 17)

The method of claim 17, wherein a first diode of the plurality of diodes is coupled via at least one of the plurality of metallization layers to a second diode of the plurality of diodes such that the second diode is a particular distance from any of the plurality of diodes.

### Claim 20 (depends on 19)

The method of claim 19, wherein the particular distance is within a range of 150 nanometers and 250 nanometers.